Ruprecht-Karls-Universität Heidelberg

Königstuhl Kolloquium


Upcoming events


2024-04-05
11:00
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Recent research results from the HKU Late State stellar evolution team - Strange Galactic alignments and solving the sulphur anomaly in Planetary Nebulae
Quentin Parker (Hong Kong)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Planetary Nebulae (Pne) are a relatively rare but powerful late-stage stellar population in terms of what we can learn about stellar evolution and the chemical enrichment process of entire Galaxies. Their ionised shells exhibit numerous and strong emission lines over a wide range of the electromagnetic spectrum. As such they represent highly useful “laboratories” for studying the plasma physics of these celestial objects.  Because most radiation from PNe is emitted via their strong emission lines they can be found to enormous distances outside of our own Galaxy. Their rich variety of lines also enables estimation of elemental abundances, expansion velocity of the nebula and associated kinematic age. HASH (Hong Kong/AAO/Strasbourg H-alpha PN catalogue) is a PNe mutliwavelength database of all currently known Galactic and Magellanic Cloud PNe. It has provided a powerful online resource for the global community to study both PNe and their CSPN with over 1100 users in more than 60 countries.

In this talk I will present some key, recent results from various HKU based projects on PNe facilitated via our ESO VLT data and HASH. I will cover a recent, enigmatic 5-sigma PNe alignment result in the Galactic centre, our robust abundance determinations and resolution of a decades old  so-called “sulphur anomaly” problem.

2024-04-12
11:00
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DSA-2000
Fabian Walter (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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TBD

2024-04-19
11:00
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TBD
Shanghuo Li (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2024-04-26
11:00
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James Kirk (Imperial)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2024-04-26
11:00
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James Kirk (Imperial)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2024-05-10
11:00
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TBD
Tom Megeath (Uni of Toledo)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract: TBA

2024-05-17
11:00
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Ryan Hickox (Dartmouth)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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KoCo signature speaker (GC)

2024-05-24
11:00
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Raphael Hviding (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2024-05-31
11:00
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Antoine Dumont (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2024-06-07
11:00
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Sarah Casewell (Leicester)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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KoCo Signature Speaker

2024-06-14
11:00
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TBD
Christina Eilers (MIT)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2024-06-21
11:00
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Selina Nitschai (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2024-06-28
11:00
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Aarynn Carter (STScI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2024-07-05
11:00
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Maximilian Häberle (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2024-07-05
11:00
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Stan Letchev
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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TBA

2024-07-12
11:00
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Maximilian Häberle (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2024-07-19
11:00
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Tushar Suhasaria (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2024-07-26
11:00
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Ian Crossfield (Kansas)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2024-09-13
11:00
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TBD
Dima Semenov (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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TBD

2024-09-20
11:00
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Jes Jørgensen (NBI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2024-09-27
11:00
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: Nicolas Bouche (CRAL)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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tbd

2024-10-11
11:00
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Mario Flock (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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TBD

2024-11-29
15:00
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@3PM
Patzer Colloquium
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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TBD


Past events


2024-03-22
11:00
What do the neighbors look like? A comparative look at the Milky Way and Andromeda dwarf galaxies
Nicolas Martin (Obs. Strasbourg)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Dwarf galaxies are powerful tools of near-field cosmology and galactic archaeology: their numbers, distribution, and star formation can be linked to both the tenets of LCDM (the missing satellite "problem," their (an)isotropic distribution, their dark matter content) and to the build up of their hosts and their environment (accretion, quenching). The exquisite detail offered by observation of the nearby Milky Way dwarf galaxies has built a picture of what dwarf galaxies are and how they evolved through time. In this talk, I will review the increasingly sharp view we are building of the dwarf-galaxy system of the Milky Way's "sister" galaxy, Andromeda, and emphasize key similarities and differences between these two systems of satellites in the hope to learn what features are common or, on the contrary, driven by the different pasts of the Milky Way and Andromeda.

2024-03-15
11:00
A planetary population synthesis look at the exoplanetary radius valley
Remo Burn (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The planetary population synthesis method can help to confront planet formation theory against observations. I will present an overview of recent works and their challenges before focusing on the radius valley in the observed exoplanet distribution. Conventionally, it is explained by the loss of primordial H/He envelopes atop rocky cores. However, this was so far inconsistent with the presence of migrated, water-rich planets which are consistently predicted by planet formation theories. In a recent work, we recover the radius valley at the observed position if we include supercritical steam atmospheres in combination with photoevaporation of mixed H/He and water. The exclusion of the lower-density supercritical phase of water was a shortcoming of previous global models and is identified as a key process.

2024-03-08
11:00
A landscape of H.E.S.S. results on indirect dark matter searches
Alessandro Montanari (LSW)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Gamma-ray observations with Imaging Atmospheric Cherenkov Telescopes (IACTs) are a unique probe for indirect detection of dark matter (DM) astrophysical signal. The scenario of TeV-scale Weakly Interactive Massive Particles - a compelling class of stable DM candidates - has been extensively explored using observations collected with the High Energy Stereoscopic System (H.E.S.S.), a hybrid array of five IACTs. After more than 20 years of stereoscopic observations, H.E.S.S. collected a variety of datasets from potential targets hosting DM with unprecedented sensitivity. Located in the Southern hemisphere, H.E.S.S. is in a privileged position to observe the Milky Way and the Galactic centre (GC) region. I will present the main results obtained with H.E.S.S. on the search for DM annihilation signals - considering also specific DM candidates like the Wino, Higgsino, and Quintuplet - from targets such as dwarf spheroidal galaxies, candidates DM subhalos in the Milky Way halo, and the GC region. These results establish a benchmark for the ultimate sensitivity of the current generation of IACT instruments to annihilating DM, providing conclusions directly relevant for searches of DM signals with the next generation of Cherenkov telescopes.

2024-03-01
11:00
Euclid - at the start of its surveys
Knud Jahnke (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
ESA's Euclid mission has been launched 9 months ago and has just started its 6-year science surveys, now scanning 10 square degrees every day. I will recap Euclid's cosmology science goals and motivate why 1000+ non-cosmologists are also eagerly waiting to use Euclid's first data. This will include an overview over Euclid's capabilities and limits, the type of data that is generated, and what kind of work to enable the mission is currently done at MPIA. I'll also give an overview of which Euclid-centered or -enabled science is planned at MPIA, how anyone interested can still get involved, including getting early access to data, and whom you can contact to about Euclid and Euclid science. And I will show the first science-ready data that were released in November, and give an outlook of which data should be expected when.

2024-02-23
11:00
The outer reaches of extrasolar systems: exoplanets, brown dwarfs and debris disks with high-contrast imaging
Elisabeth Matthews (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Direct detection of exoplanets is challenging: there is an enormous contrast barrier and a small angular separation between a star and any planets that are in orbit\; these planets are also rare, and blind surveys for these objects are expensive. However, once detected, imaged planets can provide a wealth of information about the planet atmosphere through detailed photometric and spectroscopic campaigns. To date, only a small handful of exoplanets have been directly detected, and the population consists primarily of young, hot planets which are still re-radiating their formation energy - with very little overlap with the population of indirectly detected planets. However, cold faint planets are some of the most fascinating: they are the most similar to those in our own solar system, providing context for the study of Jupiter and observationally calibrating theoretical evolution models as the planets approach equilibrium temperature. Their atmospheric chemistry is expected to be dominated by molecules such as CH4, H2O and NH3, and water clouds are also predicted. The unprecedented sensitivity of the James Webb Space Telescope allows access to this cold population of exoplanets for the first time — yet selecting appropriate targets for deep imaging campaigns is critical.

In this talk I will highlight our efforts to use ancillary information to target direct imaging campaigns and image cool planets. Radial velocity campaigns, astrometric accelerations, and debris disk signatures can all provide clues as to the best targets to image. Planets in these systems are particularly amenable to detailed characterization: for example, imaging planets in systems with debris disks allows a detailed study of the disk-planet interactions. Imaging planets with RV information allow us to simultaneously measure precise dynamical masses, bolometric luminosities, and atmospheric compositions, and characterize the orbits of these companions, and early measurements challenge evolutionary models. This technique has led to my recent discovery of the cold planet Eps Ind Ac with JWST/MIRI coronagraphic imaging. Eps Ind Ac is the oldest and coldest exoplanet ever directly imaged, and the first confirmed planet discovered with JWST imaging. Early comparison to models indicates a clear tension with both atmospheric and evolutionary models for solar-age exoplanets, but the bright flux and wide separation make this source ideally suited to future characterization efforts that may shed light on this tension.

2024-02-09
11:00
"Cosmic train-wrecks - cosmology & astrophysics with merging galaxy clusters"
Urmila Chadayammuri (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The Bullet Cluster, Pandora's Cluster, the Trainwreck Cluster - merging galaxy clusters are some of the most spectacular events in the Universe, the most energetic things to occur since the Big Bang. Because these systems are very far from equilibrium, interpreting their observations is much more challenging than in their relaxed counterparts. Powered by idealised and numerical simulations, however, they are uniquely powerful in constraining such properties as the self-interaction cross-section of dark matter, the viscosity of the intracluster medium and the strength of cosmic magnetic fields. Due to their enhanced triaxiality, they are also the most potent gravitational lenses in the Universe, revealing the galaxy and quasar populations otherwise too faint to observe, including now several candidates just half a billion years after the Big Bang. In this talk, I show examples of each of these use cases, and show how the path forward is being accelerated with machine learning and simulation-based inference.

2024-02-02
11:00
A new "Ice Age" or an astronomical meltdown? Tracing CHONs chemistry from clouds to exoplanets with JWST
Melissa McClure (Leiden Observatory)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Volatile elements, like C, H, O, N, and S, are critical to the detectability of planetary atmospheres and the origins of life as we know it. These elements are mostly carried by icy dust grains that may have been transferred to Earth from the cold outer regions of the Solar protoplanetary disk. Much of this ice likely originated in the Sun's natal molecular cloud\; however, the total amount, variety, and complexity of ices inherited this way is an open question. These questions are critical to understanding planetary habitability and the rise of life, and they could allow us to use the atmospheric composition of giant planets to trace their formation zones in protoplanetary disks.

Infrared spectroscopy of clouds, protostars, and protoplanetary disks with JWST allows us to answer these questions. I will present initial results from several Cycle 1 JWST programs, including the ERS program Ice Age (http://jwst-iceage.org/), showcasing the exquisite data quality from JWST. These observations reveal the diversity of icy chemistry found in dark regions of molecular clouds and the distribution and bulk composition of ice and gas in protostars and disks. We see early chemical pathways to complex ices and CO2 in the cloud while the distribution of CO ice in the protoplanetary disk, suggests that it is trapped in the CO2 ice matrix on the dust grains. 

These results provide additional complications in the community's efforts to connect exoplanets' atmospheric compositions with their formation histories.

2024-01-26
11:00
Unveiling the secrets of massive stars as cosmic engines
Andreas Sander (ARI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Albeit rare in absolute numbers, massive stars are shaping our cosmic history as they are connected to many astrophysical key processes. Commonly defined as stars with an initial mass of more than 8 times the mass of our Sun, massive stars are the progenitors of black holes and neutron stars, reaching all nuclear burning stages before eventually undergoing their inevitable core collapse. In their relative short, but wild life, these luminous objects have an enormous impact on their galactic environment, enriching the surrounding medium with momentum, matter and ionizing radiation. This so-called "feedback" of massive stars is a building block for the evolution of galaxies, initiating and inhibiting further star formation. In the "afterlives" of massive stars, black holes and neutron stars can merge with each other, giving rise a to Gravitational Wave events.

Many details of massive stars as well as their impact and evolution are still poorly understood. In fact, the overall picture we draw in textbooks often does not hold once we actually try to bring all the observational and theoretical constraints together. We nowadays know that many massive stars have one or more companion and interactions between massive stars are common. While this gives rise to different evolutionary channels, many challenges remain. Further unconventional puzzle pieces and surprising constraints have arrived from observational frontiers such as the strong metal-enrichment in high-redshift galaxies discovered by JWST or the black hole statistics obtained from Gravitational Waves.

Investigating the massive star puzzle with a combined approach of theory, observation and numerics is at the very heart of my research group at the ARI. Our central tool in this endeavour is the application and development of dedicated stellar atmosphere models. I will briefly introduce the techniques and challenges of atmosphere modelling for hot, massive stars and their winds as well as their empirical and theoretical applications. Afterwards, I will provide an overview about the multi-ranged research efforts in my group, ranging from the spectral analysis of individual stars and the identification of "hidden" companions over theoretical studies on radiation-driven winds up to the generation of synthetic stellar libraries and new predictions for stellar feedback.

2024-01-19
11:00
TBD
No KoCo
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2024-01-19
11:00
TBD
No KoCo
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2024-01-12
11:00
Quasars at Cosmic Dawn - before and after JWST
Eduardo Banados (MPIA)
Königstuhl Kolloquium
MPIA lecture hall,
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Abstract
Quasars are among the most powerful and luminous objects in the Universe. As such, they can be found and studied in detail far back into the epoch of reionization at redshifts z>6. These luminous quasars are ideal laboratories to study the build-up of the first massive galaxies and black holes and the onset of small- and large-scale structures in the early Universe. I will review our "pre-JWST" knowledge of the physical properties of the most distant quasars (black holes, host galaxies, and their environment). I will also highlight recent results, including from JWST, and briefly describe what to expect from the European Euclid mission. The next few years will be critical for advancing our understanding of quasars at cosmic dawn.

2024-01-12
11:00
TBD
Eduardo Banados (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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TBD

2023-12-08
11:00
The cradle of black holes: Growing intermediate-mass black holes in dense star cluster simulations
Albrecht Kamlah (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Since the first detection of gravitational waves emitted during the merger of two black holes, understanding the formation channels of such systems has become one of the most pressing questions in theoretical astrophysics. In the 19 pioneering Dragon-II simulations published this year and which I will present, we have demonstrated that the black holes the merge in our simulations can fit the observed gravitational wave sources very well. This has many implications for the entire field of computational astronomy, but also astrophysics in general. Unlike observations, we can resolve the entire lifecycle of the black holes (and other compact objects) that are gravitational wave sources from birth to eventual demise. This helps us to unravel one of the fundamental questions in astrophysics of how massive black holes form and gets us close to the question where supermassive black holes originate from. I will also highlight results from an as of yet mostly ignored parameter in such simulations, which is initial star cluster rotation and which yields exciting phenomena. Lastly, I will provide insights into the evolution of the first (Population-III) star clusters in the Universe and first results from growing actual supermassive black hole seeds within star clusters.

2023-12-08
11:00
TBD
Albrecht Kamlah (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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TBD

2023-12-01
11:00
"Revealing the 3D structure of exo-atmosphere.""
Vivien Parmentier (Université C?'te d'Azur)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Abstract: 

All planetary atmospheres are 3D in nature. This is particularly true for the majority of exoplanets we observe today : tidally-locked, close in, giant planets. Atmospheric flow from the dayside to nightside of these worlds shape the 3D thermal, chemical and cloud structure. Understanding this 3D structure is crucial to properly interpret current and future observations.


I will show how recent breakthrough in telescopes and instrumentations allow us directly measure dynamical quantities and map the 3D structure of exoplanets. I will particularly highlight how wind speeds can be directly measured from ground-based high-spectral resolution observations and how temperature, chemical and cloud maps can be obtained through JWST observations, including the recently observed NIRspec/PRISM phase curve of the hot Jupiter NGTS-10b.

Signature Speaker


2023-12-01
11:00
TBD
Vivien Parmentier (Université C?'te d'Azur)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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TBD

2023-11-24
15:00
TBD
Patzer Colloquium (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2023-11-24
11:00
TBD
Patzer Colloquium (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2023-11-24
11:00
TBD
Patzer Colloquium (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2023-11-24
11:00
TBD
Patzer Colloquium (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2023-11-17
11:00
Exoplanet transit spectroscopy in the era of JWST
Eva-Maria Ahrer (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Abstract: JWST started its science operations a year ago. Since then, there's been a large influx of atmospheric characterisation of exoplanets in the infrared, previously only partially accessible with high-resolution spectrographs or space telescopes such as Spitzer. Highlights of early JWST results include detections of carbon dioxide, the lack of detection of methane in some planets and the detection of sulphur dioxide, a product of photochemistry. The implications of these precise observations broad, from planet formation and migration history to challenging our atmospheric models.

In this talk I will give an overview of the first spectra of transiting exoplanets taken with JWST as part of the Transiting Exoplanet Community Early Release Science (TEC ERS) program, including the research I led. I will also show recent JWST observations that demonstrate its capabilities and the new insights we can
 gather about exoplanetary atmospheres, with a focus on transiting gas giants.

In addition to showing new, shiny JWST results, I will also take some time in this talk to discuss synergies between JWST and other telescopes and demonstrate that observations in the bluer wavelength ranges are also necessary to fully characterise an exoplanet's atmosphere.

In the final part of this talk, I will show a few examples of upcoming JWST exoplanetary science that I'm particularly excited about.

2023-11-17
11:00
TBD
Vivien Parmentier (University of Oxford)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2023-11-17
11:00
TBD
Eva-Maria Ahrer (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2023-11-10
11:00
Tools for Understanding the Cosmic History of Molecular Gas
Ryan Keenan (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract

As the fuel for star formation, molecular gas plays a crucial role in the evolution of galaxies. Advanced millimeter-wave facilities now make it possible to study the gas properties of large samples of nearby galaxies and to peer into the cold ISM of “typical” star forming galaxies throughout cosmic time. However, many details of the interplay between gas and star formation that drives galaxy evolution remain unsettled. In this talk, I will present my work refining our tools for measuring and interpreting the observational signatures of molecular gas. I will begin by reviewing recent efforts to measure the cosmic abundance of molecular gas, and its evolution over time. Pioneering studies with ALMA, NOEMA, and the VLA have now constrained the global history of molecular gas to cosmic noon and beyond. Achieving precision measurements of this history will require extensive surveys which push the limits of current facilities. I have developed mocks for current and future surveys to help guide the design of the next generation of molecular gas deep fields. Precision measurements of the cosmic molecular gas history require surveys over significantly larger volumes than have been achieved to date, and I will discuss possible avenues for accomplishing such a survey. The novel technique of “line intensity mapping” (LIM), which can constrain the agreagate gas content of galaxies too faint to be individually detected, provides one path forward using existing facilities. I will provide an overview of the LIM technique, highlight a few upcoming line intensity mapping projects, and present upper limits on the CO-galaxy cross-power spectrum at redshift 2 derived from the exploratory CO Power Spectrum Survey, which serve as a proof of concept for future projects.

 

While much of our understanding of molecular gas comes from studies using the CO(1-0) line, other tracers gas tracers such as the higher energy CO lines, are increasingly popular. In the second half of my talk I will introduce the Arizona Molecular ISM Survey with the SMT (AMISS), a multi-line study of 177 nearby galaxies designed cross-calibrate the CO(1-0), CO(2-1), and CO(3-2) lines as tracers of molecular gas. The large sample and careful calibration of AMISS make it possible to robustly measure correlations between the excitation of CO emitting gas and host galaxy properties on a galaxy integrated scale. The three lines are not perfectly interchangeable tracers and the luminosity ratios between them vary systematically over the galaxy population. Using the AMISS sample, I characterize these trends, providing an empirical prescription for translating between gas measurements made with different CO lines, and then explore the utility of CO line ratios as diagnostics of conditions in the interstellar media of galaxies.


2023-11-03
11:00
Inner Disk Chemistry in the JWST Era
Giulia Perotti (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Protoplanetary disks represent the evolutionary link between molecular clouds and planets. Knowledge of their molecular inventory is the key to unveil the chemical trail leading to life, yet too few observational constraints of disks exist at infrared wavelengths. This wavelength regime enables to study the solid and gas reservoirs where terrestrial planets and sub-Neptunes form. Compared to previous IR facilities, the JWST MIRI instrument offers unprecedented sensitivity, spatial resolution (R=3400-1600), and spectral coverage (5-28 µm). In this KoCo, I will present the first MIRI MRS observations of the PDS 70 planet-forming disk as part of the MIRI Mid-INfrared Disk Survey (MINDS). The much higher spectral resolution of MIRI MRS compared with previous Spitzer spectroscopy (R=100, 600) reveals emission of water vapour. This demonstrates that the terrestrial planet-forming zone of PDS 70 has maintained to some degree the physical and chemical conditions of young disks, in spite of the 54 au planet-induced gap.

2023-11-03
11:00
tbd
Giulia Perotti (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
tbd

2023-10-27
11:00
TBD
TBD (TBD)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2023-10-20
11:00
Zooming in on the Baryon Cycle in Galaxies
Christopher Faesi (UConn)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The cycling of baryons between phases of the interstellar medium (ISM) and stars drives the dynamical and chemical evolution of galaxies. One major inherent challenge lies in understanding how individual star-forming regions (parsec-scale) couple spatially and temporally to entire galaxies on kilo-parsec scales. Recent multiwavelength wide-field, high-resolution observations are beginning to shed light on how the phases of the baryon cycle are structured across star-forming galaxy disks. In particular, I will show that molecular gas tends to sit near virial equilibrium across a range of environments, but that there is no “magic scale” at which structures become gravitationally bound. I will also discuss work refining star formation rate and metallicity calculations in galaxies at the individual HII region scale. Finally, I will present JWST observations and modeling that show that mid-IR emission is (1) a robust tracer of the bulk cold ISM, and (2) able to diagnose detailed dust properties at high resolution in galaxies.

2023-10-13
11:00
The Galactic Center black hole with GRAVITY
Felix Widmann (MPE)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The black hole SgrA* at the center of our galaxy offers the unique possibility to probe General Relativity in an unexplored regime and to study the accretion physics around a supermassive black hole. The proximity of SgrA* allows us to directly observe stars orbiting the black hole and measure emission from the accretion flow of the black hole.
With the unprecedented resolution and sensitivity of the interferometric instrument GRAVITY, we push the observations of the Galactic Center to a new level. In this talk, I will summarize the results achieved with GRAVITY so far and highlight the latest developments. I will talk about the search for ever-fainter stars in close orbits around SgrA*, which allow us to measure the effects of General Relativity in the star's orbits. I will also demonstrate how we can use brightness excursions in SgrA*'s accretion flow (so-called flares) to understand the physics around supermassive black holes. The recent addition of polarimetry allows us to combine the astrometric motion of flares with observed swings in the polarization angle to study the magnetic field around SgrA*. Combining these two measurements enables us to understand better the accretion flow and the physics around the supermassive black hole.

2023-10-13
11:00
TBD
Felix Widmann (MPE)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2023-10-06
11:00
“Elemental" Insights Into Massive Galaxy Formation
Mariska Kriek (Leiden Obs.)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The chemical compositions of massive galaxies offer a unique view into their formation histories. While metals have been extensively studied in galaxies up to z~4, beyond z=0.7, the majority of studies have focused on star-forming galaxies. Measuring metallicities for distant quiescent galaxies is exceptionally challenging, as it relies on detecting faint stellar absorption features, shifted into the near-infrared wavelength regime. However, quiescent galaxies dominate the high-mass end of the galaxy population up to z~2.5, and thus it is crucial to extend their metal studies to earlier epochs as well. In this colloquium, I will present new elemental abundance measurements of massive quiescent galaxies up to z~2.3 and discuss their implications for understanding chemical enrichment, star formation, and assembly histories. I will discuss the emerging picture of massive galaxy growth over the past 11 billion years, based on these new metallicity studies, combined with similar studies at lower redshifts and measurements of other physical properties. Finally, I will present an overview of ongoing programs with the James Webb Space Telescope (JWST), which will further advance our understanding in this field.


MPIA signature speaker @ KoCo

2023-10-06
11:00
TBA
Mariska Kriek
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA


MPIA signature speaker @ KoCo

2023-09-29
11:00
Improving the census of open clusters with Gaia data and machine learning
Emily Hunt (LSW)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Open clusters are one of the most useful places in the universe for studies of stellar and galactic evolution. Formed when stars collapse from the same molecular cloud into a gravitationally bound cluster, open clusters offer a unique way to study stars of a homogeneous age and chemical composition across a range of masses. This property means they are useful objects for many different areas of astronomy, and accurately cataloguing them is hence important. In this talk, I will present the work I conducted during my PhD, aiming to improve a number of aspects of the census of open clusters in the age  of Gaia. After an introduction to the field, I will start by discussing different unsupervised machine learning algorithms for detecting clusters in the billion-star dataset of Gaia. Next, I will present our recently published catalogue of over 7000 clusters, which represents the largest homogeneous unduplicated catalogue of open clusters to date, including cluster classifications and parameters calculated with approximate Bayesian neural networks. Finally, I will discuss upcoming work on better defining open clusters observationally, which will revolutionise how open clusters can be distinguished from unbound moving groups and associations.

2023-09-29
11:00
Improving the census of open clusters with Gaia data and machine learning
Emily Hunt (LSW)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Open clusters are one of the most useful places in the universe for studies of stellar and galactic evolution. Formed when stars collapse from the same molecular cloud into a gravitationally bound cluster, open clusters offer a unique way to study stars of a homogeneous age and chemical composition across a range of masses. This property means they are useful objects for many different areas of astronomy, and accurately cataloguing them is hence important. In this talk, I will present the work I conducted during my PhD, aiming to improve a number of aspects of the census of open clusters in the age  of Gaia. After an introduction to the field, I will start by discussing different unsupervised machine learning algorithms for detecting clusters in the billion-star dataset of Gaia. Next, I will present our recently published catalogue of over 7000 clusters, which represents the largest homogeneous unduplicated catalogue of open clusters to date, including cluster classifications and parameters calculated with approximate Bayesian neural networks. Finally, I will discuss upcoming work on better defining open clusters observationally, which will revolutionise how open clusters can be distinguished from unbound moving groups and associations.

2023-09-22
11:00
ALMA reveals dust in galaxies at high redshift
Rebecca Bowler (Manchester)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
I will present an overview of what is known about dust in high-redshift galaxies and what this can tell us about early star formation and metal enrichment.  The advent of sensitive mm/sub-mm observations from ALMA and other facilities has opened up the field of direct detection of dust and FIR emission lines in normal galaxies for the first time at z > 6.  From the first detections in individual sources (e.g. the well studied A1689-zD1 at z = 7.13) almost a decade ago the field has gained momentum with blind surveys (such as the ALMA UDF) and large programs targeting the more massive and rare sources (such as ALPINE and REBELS) providing a wealth of data to probe the presence of early dust.  Despite programs such as REBELS targeting rest-UV bright galaxies, these results have surprisingly revealed a significant obscured fraction of star-formation within "normal" galaxies (f_obs > 0.5) even beyond z = 7.  In the cases where there is higher resolution ALMA + HST + JWST data available, a diversity of dust morphologies is found,  with some regions in the galaxy being HST and even JWST-dark, highlighting the key importance of direct dust detections with ALMA.   The dust attenuation law (and hence composition) can be probed via scaling relations such as the "Infrared-excess-beta" relation, and I will present recent results from a compilation of 160 galaxies at z = 4-8 from the ALPINE and REBELS surveys.  I will end by discussing the most pressing open questions and challenges: what is the dust temperature, what is the star-dust geometry and how much star-formation in the early universe is obscured/HST-dark?

MPIA signature speaker at KoCo

2023-09-22
11:00
ALMA reveals dust in galaxies at high redshift
Rebecca Bowler (Manchester)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
I will present an overview of what is known about dust in high-redshift galaxies and what this can tell us about early star formation and metal enrichment.  The advent of sensitive mm/sub-mm observations from ALMA and other facilities has opened up the field of direct detection of dust and FIR emission lines in normal galaxies for the first time at z > 6.  From the first detections in individual sources (e.g. the well studied A1689-zD1 at z = 7.13) almost a decade ago the field has gained momentum with blind surveys (such as the ALMA UDF) and large programs targeting the more massive and rare sources (such as ALPINE and REBELS) providing a wealth of data to probe the presence of early dust.  Despite programs such as REBELS targeting rest-UV bright galaxies, these results have surprisingly revealed a significant obscured fraction of star-formation within "normal" galaxies (f_obs > 0.5) even beyond z = 7.  In the cases where there is higher resolution ALMA + HST + JWST data available, a diversity of dust morphologies is found,  with some regions in the galaxy being HST and even JWST-dark, highlighting the key importance of direct dust detections with ALMA.   The dust attenuation law (and hence composition) can be probed via scaling relations such as the "Infrared-excess-beta" relation, and I will present recent results from a compilation of 160 galaxies at z = 4-8 from the ALPINE and REBELS surveys.  I will end by discussing the most pressing open questions and challenges: what is the dust temperature, what is the star-dust geometry and how much star-formation in the early universe is obscured/HST-dark?

MPIA signature speaker at KoCo

2023-09-15
11:00
The Milky Way Laboratory
Cara Battersby (UConn)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Galaxy centers are the hubs of activity that drive galaxy evolution, from supermassive black holes to feedback from dense stellar clusters. While the bulk of our Milky Way Galaxy is a prime example of present epoch “normal” star formation, our galaxy's center has gas properties that are more reminiscent of star formation during its cosmic peak. In our research group, the Milky Way Laboratory, we capitalize on both the “normal” and “extreme” star formation in our own cosmic backyard in order to resolve the interplay of physical processes in detail. In this talk, I will discuss efforts to measure how stars gain their mass and how the star formation process may vary across the Galaxy. In our galaxy's central molecular zone, the process of star formation is complicated by constant gas inflow, high levels of turbulence, and more. I will present both simulations and observations toward this region that aim to understand the role of the gas inflow, the 3-D geometry of the region, properties of the gas, and incipient star formation.

2023-09-15
11:00
TBA
Rebecca Bowler (Manchester)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

MPIA signature speaker at KoCo

2023-09-15
11:00
The Milky Way Laboratory
Cara Battersby (UConn)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Galaxy centers are the hubs of activity that drive galaxy evolution, from supermassive black holes to feedback from dense stellar clusters. While the bulk of our Milky Way Galaxy is a prime example of present epoch “normal” star formation, our galaxy's center has gas properties that are more reminiscent of star formation during its cosmic peak. In our research group, the Milky Way Laboratory, we capitalize on both the “normal” and “extreme” star formation in our own cosmic backyard in order to resolve the interplay of physical processes in detail. In this talk, I will discuss efforts to measure how stars gain their mass and how the star formation process may vary across the Galaxy. In our galaxy's central molecular zone, the process of star formation is complicated by constant gas inflow, high levels of turbulence, and more. I will present both simulations and observations toward this region that aim to understand the role of the gas inflow, the 3-D geometry of the region, properties of the gas, and incipient star formation.

2023-09-08
11:00
The Galactic Center: Insights from K-band spectroscopy
Anja Feldmeier-Krause (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract

The Galactic center region has a mass of ~10^9 M_sun. It consists of the nuclear stellar disk (NSD), a flat, rotating stellar structure, and the nuclear star cluster (NSC), the densest concentration of stars in the Galaxy. 

The NSC and NSD are distinct structures of the Milky Way, but also connected to the larger Milky Way structures, e.g. via the inflow and outflow of gas, and the infall of star clusters. Our knowledge of the larger Milky Way structures, Galactic disc, bulge and halo, has expanded in recent years through surveys and dedicated missions. Hidden behind large amounts of interstellar dust, the Galactic centre structures, NSC and NSD, are inaccessible for these surveys, and they miss an important piece for our understanding of the Milky Way's formation and evolution. 

In this talk I will present spectroscopic observations of the Galactic centre, resulting in >\;2,500 stellar spectra. I will show the spatial distribution of young (few Myr old) stars, the metallicity distribution of the older (several Gyr) red giant stars, and spatial variations of the metallicity distribution. 


2023-09-08
11:00
TBA
Rajika Kuruwita (HITS)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2023-09-08
11:00
The Galactic Center: Insights from K-band spectroscopy
Anja Feldmeier-Krause (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract

The Galactic center region has a mass of ~10^9 M_sun. It consists of the nuclear stellar disk (NSD), a flat, rotating stellar structure, and the nuclear star cluster (NSC), the densest concentration of stars in the Galaxy. 

The NSC and NSD are distinct structures of the Milky Way, but also connected to the larger Milky Way structures, e.g. via the inflow and outflow of gas, and the infall of star clusters. Our knowledge of the larger Milky Way structures, Galactic disc, bulge and halo, has expanded in recent years through surveys and dedicated missions. Hidden behind large amounts of interstellar dust, the Galactic centre structures, NSC and NSD, are inaccessible for these surveys, and they miss an important piece for our understanding of the Milky Way's formation and evolution. 

In this talk I will present spectroscopic observations of the Galactic centre, resulting in >\;2,500 stellar spectra. I will show the spatial distribution of young (few Myr old) stars, the metallicity distribution of the older (several Gyr) red giant stars, and spatial variations of the metallicity distribution. 


2023-09-01
11:00
"Direct Imaging and Characterization of Exoplanets with JWST and Beyond"
Sasha Hinkley (Uni of Exeter)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Abstract: Almost all of the extrasolar planets identified to date have only been indirectly detected based on some effect they have on their host star's light.  However, we now have direct images of a number of massive gaseous exoplanets at wide orbital separations.  This collection of directly imaged exoplanets is already providing valuable atmospheric characterization, especially with new observatories such as the James Webb Space Telescope (JWST).  Exoplanet direct imaging with JWST is allowing us to address some of the most fundamental questions in exoplanetary science, such as the degree to which we can link our measurements of the atmospheric compositions of exoplanets with their formation history. JWST is also likely to help us gain a much more complete picture of the overall demographics of exoplanets, especially at wide orbital separations.  I will also discuss how the Gaia mission is already starting to point the way to numerous more such exoplanets suitable for direct imaging.  Characterization of these self-luminous planets will enlighten their earliest thermal histories, still the greatest source of uncertainty for theoretical models of planet formation.  Lastly, I will discuss upcoming observations in the next decades which should have the capability to directly observe and characterize Earth-like planets in the habitable zones of their host stars. 

2023-09-01
11:00
"Direct Imaging and Characterization of Exoplanets with JWST and Beyond"
Sasha Hinkley (Uni of Exeter)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Abstract: Almost all of the extrasolar planets identified to date have only been indirectly detected based on some effect they have on their host star's light.  However, we now have direct images of a number of massive gaseous exoplanets at wide orbital separations.  This collection of directly imaged exoplanets is already providing valuable atmospheric characterization, especially with new observatories such as the James Webb Space Telescope (JWST).  Exoplanet direct imaging with JWST is allowing us to address some of the most fundamental questions in exoplanetary science, such as the degree to which we can link our measurements of the atmospheric compositions of exoplanets with their formation history. JWST is also likely to help us gain a much more complete picture of the overall demographics of exoplanets, especially at wide orbital separations.  I will also discuss how the Gaia mission is already starting to point the way to numerous more such exoplanets suitable for direct imaging.  Characterization of these self-luminous planets will enlighten their earliest thermal histories, still the greatest source of uncertainty for theoretical models of planet formation.  Lastly, I will discuss upcoming observations in the next decades which should have the capability to directly observe and characterize Earth-like planets in the habitable zones of their host stars. 

2023-08-11
11:00
The JWST view on ice and gas during star and planet formation
Giulia Perotti (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2023-08-04
11:00
Magnetic Fields in the Milky Way and the Small Magellanic Cloud
Jackie Ma (ANU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The magnetic field is a crucial constituent of the interstellar medium, and accurately understanding its strength and structure in galaxies has significant implications for various areas of galactic astrophysics. Recent advancements in sensitivity and frequency coverage of radio telescopes have provided clearer insights into the magnetic fields of our Milky Way Galaxy and its neighbouring Small Magellanic Cloud (SMC). In this talk, I will share the new magnetic knowledge gained from these advanced radio instruments, using both linear polarisation and high-resolution HI measurements. In the case of the Milky Way, I utilised the Faraday rotation experienced by linearly polarised emission from extragalactic radio sources to find that (1) contrary to theoretical expectations, the galactic-scale magnetic field in the Galactic disk can reverse its direction across the mid-plane towards the Sagittarius spiral arm, and (2) the Galactic magnetic structures can undergo significant changes at <~ 10" scales, most likely due to the anisotropic turbulent magnetic fields shaped by compression and shearing. Meanwhile in the SMC, I find that the filamentary HI structures near its centre are preferentially aligned with the magnetic fields traced by starlight polarisation, suggesting that these HI structures can have the potential of being a new 3D tracer of the SMC's plane-of-sky magnetic field. I will conclude by highlighting the exciting prospects in magnetism studies offered by on-going southern sky radio survey, such as the POSSUM survey in polarisation and the GASKAP survey in HI.

2023-08-04
11:00
Magnetic Fields in the Milky Way and the Small Magellanic Cloud
Jackie Ma (ANU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The magnetic field is a crucial constituent of the interstellar medium, and accurately understanding its strength and structure in galaxies has significant implications for various areas of galactic astrophysics. Recent advancements in sensitivity and frequency coverage of radio telescopes have provided clearer insights into the magnetic fields of our Milky Way Galaxy and its neighbouring Small Magellanic Cloud (SMC). In this talk, I will share the new magnetic knowledge gained from these advanced radio instruments, using both linear polarisation and high-resolution HI measurements. In the case of the Milky Way, I utilised the Faraday rotation experienced by linearly polarised emission from extragalactic radio sources to find that (1) contrary to theoretical expectations, the galactic-scale magnetic field in the Galactic disk can reverse its direction across the mid-plane towards the Sagittarius spiral arm, and (2) the Galactic magnetic structures can undergo significant changes at <~ 10" scales, most likely due to the anisotropic turbulent magnetic fields shaped by compression and shearing. Meanwhile in the SMC, I find that the filamentary HI structures near its centre are preferentially aligned with the magnetic fields traced by starlight polarisation, suggesting that these HI structures can have the potential of being a new 3D tracer of the SMC's plane-of-sky magnetic field. I will conclude by highlighting the exciting prospects in magnetism studies offered by on-going southern sky radio survey, such as the POSSUM survey in polarisation and the GASKAP survey in HI.

2023-07-28
11:00
Radiative modeling of extended relativistic jets
Michael Zacharias (LSW)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract

Blazars are those kinds of active galactic nuclei, where the relativistic jet points towards Earth. Due to relativistic beaming, the processes inside the jet can be studied in great detail. Kinetic radiation codes provide an excellent opportunity to obtain the particle distributions and to describe interaction processes within the jet, as well as to model the radiative output of the jet. Here, I will present the code "ExHaLe-jet" that describes extended jets considering both leptonic and hadronic processes. I will highlight the influence of thermal photon sources external to the jet, which are prime targets for particle-photon interactions inside the jet.
In a second part of the talk, I will discuss a recent observational result, where a blazar jet seems to suddenly, partially switch off. 


2023-07-28
11:00
Radiative modeling of extended relativistic jets
Michael Zacharias (LSW)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract

Blazars are those kinds of active galactic nuclei, where the relativistic jet points towards Earth. Due to relativistic beaming, the processes inside the jet can be studied in great detail. Kinetic radiation codes provide an excellent opportunity to obtain the particle distributions and to describe interaction processes within the jet, as well as to model the radiative output of the jet. Here, I will present the code "ExHaLe-jet" that describes extended jets considering both leptonic and hadronic processes. I will highlight the influence of thermal photon sources external to the jet, which are prime targets for particle-photon interactions inside the jet.
In a second part of the talk, I will discuss a recent observational result, where a blazar jet seems to suddenly, partially switch off. 


2023-07-21
11:00
First Stars: Formation, Properties, and Impact
Ralf Klessen (ITA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The first generation of stars, often called Population III (or Pop III), form from metal-free primordial gas at redshifts z ~ 30 and below. They dominate the cosmic star formation history until z ~ 20-15, at which point the formation of metal-enriched Pop II stars takes over. I review current theoretical models for the formation, properties and impact of Pop III stars, and discuss observational constraints. I argue that primordial gas is highly susceptible to fragmentation and Pop III stars form as members of small clusters with a logarithmically flat mass function. Feedback from massive Pop III stars plays a central role in regulating subsequent star formation, but major uncertainties remain regarding its immediate impact. Direct observations of Pop III stars in the early Universe remain extremely challenging, whereas stellar archeological surveys allow us to constrain both the low-mass and the high-mass ends of the Pop III mass distribution. Observations suggest that most massive Pop III stars end their lives as core-collapse supernovae rather than as pair-instability supernovae.

2023-07-21
11:00
First Stars: Formation, Properties, and Impact
Ralf Klessen (ITA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The first generation of stars, often called Population III (or Pop III), form from metal-free primordial gas at redshifts z ~ 30 and below. They dominate the cosmic star formation history until z ~ 20-15, at which point the formation of metal-enriched Pop II stars takes over. I review current theoretical models for the formation, properties and impact of Pop III stars, and discuss observational constraints. I argue that primordial gas is highly susceptible to fragmentation and Pop III stars form as members of small clusters with a logarithmically flat mass function. Feedback from massive Pop III stars plays a central role in regulating subsequent star formation, but major uncertainties remain regarding its immediate impact. Direct observations of Pop III stars in the early Universe remain extremely challenging, whereas stellar archeological surveys allow us to constrain both the low-mass and the high-mass ends of the Pop III mass distribution. Observations suggest that most massive Pop III stars end their lives as core-collapse supernovae rather than as pair-instability supernovae.

2023-07-14
11:00
Robustly Characterizing Exoplanets in a New Era of High-Precision Transit Measurements
Julian De Wit (MIT)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract

With a new-generation of great observatories coming online this decade, unprecedented insights into exoplanets will soon be within reach. Observatories such as the James Webb Space Telescope (JWST) notably enable the study of atmospheres around terrestrial exoplanets and can reveal tri-dimensional structures in the atmospheres of their larger counterparts. Robustly leveraging new observations to reach such achievements will however require extra care as the models currently used may not be up to par with their precision. 

During this presentation, I will introduce work done by MIT's Disruptive Planets group and collaborators towards supporting the robust in-depth characterization of exoplanets. I will specifically discuss how not accounting for the true shape of a planet can lead to a misinterpretation of its interior properties as well as atmospheric structure\; how the current state of our understanding of light-matter interactions can similarly affect our interpretation of planetary spectra and thus inferences regarding their atmospheric properties\; and how the current state of emission spectrum models for stars may even prevent from disentangling between the contribution of a planet and its host star, to start with.  I will also present possible ways to address these challenges. I will end with a step-by-step roadmap to the robust characterization of temperate terrestrial planets with JWST, which includes habitability assessment


2023-07-14
11:00
Robustly Characterizing Exoplanets in a New Era of High-Precision Transit Measurements
Julian De Wit (MIT)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract

With a new-generation of great observatories coming online this decade, unprecedented insights into exoplanets will soon be within reach. Observatories such as the James Webb Space Telescope (JWST) notably enable the study of atmospheres around terrestrial exoplanets and can reveal tri-dimensional structures in the atmospheres of their larger counterparts. Robustly leveraging new observations to reach such achievements will however require extra care as the models currently used may not be up to par with their precision. 

During this presentation, I will introduce work done by MIT's Disruptive Planets group and collaborators towards supporting the robust in-depth characterization of exoplanets. I will specifically discuss how not accounting for the true shape of a planet can lead to a misinterpretation of its interior properties as well as atmospheric structure\; how the current state of our understanding of light-matter interactions can similarly affect our interpretation of planetary spectra and thus inferences regarding their atmospheric properties\; and how the current state of emission spectrum models for stars may even prevent from disentangling between the contribution of a planet and its host star, to start with.  I will also present possible ways to address these challenges. I will end with a step-by-step roadmap to the robust characterization of temperate terrestrial planets with JWST, which includes habitability assessment


2023-07-07
11:00
Paradigm Shifts in Galaxy Formation and Cosmic Rays (and Quasar Fueling)
Philip Hopkins (Caltech)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Simulations of galaxy formation and evolution have led to a number of new insights and paradigm shifts in the last decade. A first is that the “clustering” of star formation in both space and time (aka “bursty” star formation) qualitatively changes the dynamics of star formation itself, stellar “feedback” from radiation and supernovae, and therefore galaxy structure and formation, and even the dark matter structure of galaxies. There is now growing agreement that galaxies pass through some bursty, turbulent, disordered phase before (if they are massive enough) “settling down” to form disks with calmer star formation. I'll review how and why this process occurs, and how we can identify the most important physics at play. A second paradigm shift has come with modeling of cosmic rays. I'll review how there has been a sea change in our understanding both of how these particles could influence the formation of galaxies and stars, and how they actually move through and interact with the interstellar medium on astrophysical “micro-scales,” raising much more fundamental un-solved space plasma physics questions. Finally, on quasars, I'll (very briefly) advertise the first numerical simulations which can self-consistently resolve scales from the intergalactic medium down to the formation of accretion disks powering the most luminous sources in the Universe.

2023-07-07
11:00
Paradigm Shifts in Galaxy Formation and Cosmic Rays (and Quasar Fueling)
Philip Hopkins (Caltech)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Simulations of galaxy formation and evolution have led to a number of new insights and paradigm shifts in the last decade. A first is that the “clustering” of star formation in both space and time (aka “bursty” star formation) qualitatively changes the dynamics of star formation itself, stellar “feedback” from radiation and supernovae, and therefore galaxy structure and formation, and even the dark matter structure of galaxies. There is now growing agreement that galaxies pass through some bursty, turbulent, disordered phase before (if they are massive enough) “settling down” to form disks with calmer star formation. I'll review how and why this process occurs, and how we can identify the most important physics at play. A second paradigm shift has come with modeling of cosmic rays. I'll review how there has been a sea change in our understanding both of how these particles could influence the formation of galaxies and stars, and how they actually move through and interact with the interstellar medium on astrophysical “micro-scales,” raising much more fundamental un-solved space plasma physics questions. Finally, on quasars, I'll (very briefly) advertise the first numerical simulations which can self-consistently resolve scales from the intergalactic medium down to the formation of accretion disks powering the most luminous sources in the Universe.

2023-06-30
11:00
Predictions for the faint Lyman-alpha cosmic web
Chris Byrohl (ZAH/ITA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Neutral hydrogen in the filaments of the cosmic web may be observable through emission of the Lyman-alpha line. Although luminous Lyman-alpha emitters are already an established tracer of the matter distribution in the high-redshift universe, the implications of the faint Lyman-alpha glow within the cosmic web, away from luminous emitters, are yet to be explored. In this talk, I will discuss the nature of large-scale, diffuse Lyman-alpha filaments and their detectability with recent integral field spectrographs such as VLT-MUSE, K-CWI, and HET-VIRUS. To explore this, we combine recent cosmological magnetohydrodynamical galaxy formation simulations with explicit calculation of the Lyman-alpha radiative transfer. We find that observable filaments are illuminated by Lyman-alpha photons that are emitted from the circumgalactic medium of intermediate-mass halos, rather than from the filaments themselves. These photons then escape and scatter within their surrounding, substantially boosting the Lyman-alpha signal from diffuse filaments. Our work provides a reference model for Lyman-alpha filaments, and demonstrates the importance and complexities of Lyman-alpha radiative transfer across spatial scales.

2023-06-30
11:00
Predictions for the faint Lyman-alpha cosmic web
Chris Byrohl (ZAH/ITA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Neutral hydrogen in the filaments of the cosmic web may be observable through emission of the Lyman-alpha line. Although luminous Lyman-alpha emitters are already an established tracer of the matter distribution in the high-redshift universe, the implications of the faint Lyman-alpha glow within the cosmic web, away from luminous emitters, are yet to be explored. In this talk, I will discuss the nature of large-scale, diffuse Lyman-alpha filaments and their detectability with recent integral field spectrographs such as VLT-MUSE, K-CWI, and HET-VIRUS. To explore this, we combine recent cosmological magnetohydrodynamical galaxy formation simulations with explicit calculation of the Lyman-alpha radiative transfer. We find that observable filaments are illuminated by Lyman-alpha photons that are emitted from the circumgalactic medium of intermediate-mass halos, rather than from the filaments themselves. These photons then escape and scatter within their surrounding, substantially boosting the Lyman-alpha signal from diffuse filaments. Our work provides a reference model for Lyman-alpha filaments, and demonstrates the importance and complexities of Lyman-alpha radiative transfer across spatial scales.

2023-06-30
11:00
Predictions for the faint Lyman-alpha cosmic web
Chris Byrohl (ZAH/ITA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Neutral hydrogen in the filaments of the cosmic web may be observable through emission of the Lyman-alpha line. Although luminous Lyman-alpha emitters are already an established tracer of the matter distribution in the high-redshift universe, the implications of the faint Lyman-alpha glow within the cosmic web, away from luminous emitters, are yet to be explored. In this talk, I will discuss the nature of large-scale, diffuse Lyman-alpha filaments and their detectability with recent integral field spectrographs such as VLT-MUSE, K-CWI, and HET-VIRUS. To explore this, we combine recent cosmological magnetohydrodynamical galaxy formation simulations with explicit calculation of the Lyman-alpha radiative transfer. We find that observable filaments are illuminated by Lyman-alpha photons that are emitted from the circumgalactic medium of intermediate-mass halos, rather than from the filaments themselves. These photons then escape and scatter within their surrounding, substantially boosting the Lyman-alpha signal from diffuse filaments. Our work provides a reference model for Lyman-alpha filaments, and demonstrates the importance and complexities of Lyman-alpha radiative transfer across spatial scales.

2023-06-23
11:00
Ultra-Diffuse Galaxies (UDGs) and the Stellar Mass – Halo Mass Relationship
Jonah Gannon (Swinburne University)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The stellar mass – halo mass relationship is a fundamental scaling relationship connecting galaxies from dwarfs to giants to their dark matter halos. This relationship is currently key to our understanding of the complex interplay between the many modes of feedback (e.g., stellar winds, supernovae, AGN) and star formation in galaxies. However, recently a population of large half-light radius, low surface brightness ultra-diffuse galaxies (UDGs) have questioned our understanding of galaxy formation in the dwarf galaxy regime. UDGs have been found to reside in dark matter halos of widely varying mass. While many likely reside in “normal” dark matter halos for their stellar mass, some may exhibit an extreme lack of dark matter while yet others are extremely dark matter rich. In this talk, I give an overview of the current observational evidence for UDGs residing in massive dark matter halos. I place particular emphasis on my own Keck observations which have provided support for UDGs' unexpected stellar mass – halo mass positioning and that has revealed the internal structure of their halo (i.e., core vs cusp nature). I discuss how these observations currently inform proposed formation scenarios for UDGsand show an outstanding tension of my observations with simulations of galaxy formation. I conclude with a brief discussion of the important future goals of the field.

2023-06-23
11:00
TBD
Jonah Gannon (Swinburne University)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2023-06-23
11:00
Ultra-Diffuse Galaxies (UDGs) and the Stellar Mass – Halo Mass Relationship
Jonah Gannon (Swinburne University)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
The stellar mass – halo mass relationship is a fundamental scaling relationship connecting galaxies from dwarfs to giants to their dark matter halos. This relationship is currently key to our understanding of the complex interplay between the many modes of feedback (e.g., stellar winds, supernovae, AGN) and star formation in galaxies. However, recently a population of large half-light radius, low surface brightness ultra-diffuse galaxies (UDGs) have questioned our understanding of galaxy formation in the dwarf galaxy regime. UDGs have been found to reside in dark matter halos of widely varying mass. While many likely reside in “normal” dark matter halos for their stellar mass, some may exhibit an extreme lack of dark matter while yet others are extremely dark matter rich. In this talk, I give an overview of the current observational evidence for UDGs residing in massive dark matter halos. I place particular emphasis on my own Keck observations which have provided support for UDGs' unexpected stellar mass – halo mass positioning and that has revealed the internal structure of their halo (i.e., core vs cusp nature). I discuss how these observations currently inform proposed formation scenarios for UDGsand show an outstanding tension of my observations with simulations of galaxy formation. I conclude with a brief discussion of the important future goals of the field.

2023-06-16
11:00
Star formation and stellar populations in galactic bars
Justus Neumann (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
After a vigorous formation phase driven by mergers and galaxy interactions at early epochs, the evolution of galaxies has been dominated by relatively slow, so-called secular evolution over at least half of the Universe's lifetime. While a large number of today's characteristics of galaxies are generated during this phase, we still lack a solid understanding of the astro-physical processes at play. In this talk, I will present some of my work studying galaxy bars - the main drivers of internal galaxy evolution.

Bars as non-axisymmetric structures have been shown to greatly impact the distribution of stars, gas and angular momentum in galaxies. By studying stellar populations as archaeological relics in the central parts of barred galaxies we are able to learn about processes during bar formation and bar evolution. Furthermore, when looking at current and ongoing star formation, we find that about half of all nearby barred galaxies show signatures of star formation along the bar, while the other half presents itself with a curious absence of star formation. Despite the presence of cold molecular gas observed as radial flows along the edge of the bar towards the galaxy centre, the local environment seems to be able to suppress star formation. By using integral field spectrographs such as VLT/MUSE and eBOSS/MaNGA, I will present what we can learn from studies of star formation and stellar populations in galactic bars.

2023-06-16
11:00
TBD
Justus Neumann (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2023-06-16
11:00
Star formation and stellar populations in galactic bars
Justus Neumann (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
After a vigorous formation phase driven by mergers and galaxy interactions at early epochs, the evolution of galaxies has been dominated by relatively slow, so-called secular evolution over at least half of the Universe's lifetime. While a large number of today's characteristics of galaxies are generated during this phase, we still lack a solid understanding of the astro-physical processes at play. In this talk, I will present some of my work studying galaxy bars - the main drivers of internal galaxy evolution.

Bars as non-axisymmetric structures have been shown to greatly impact the distribution of stars, gas and angular momentum in galaxies. By studying stellar populations as archaeological relics in the central parts of barred galaxies we are able to learn about processes during bar formation and bar evolution. Furthermore, when looking at current and ongoing star formation, we find that about half of all nearby barred galaxies show signatures of star formation along the bar, while the other half presents itself with a curious absence of star formation. Despite the presence of cold molecular gas observed as radial flows along the edge of the bar towards the galaxy centre, the local environment seems to be able to suppress star formation. By using integral field spectrographs such as VLT/MUSE and eBOSS/MaNGA, I will present what we can learn from studies of star formation and stellar populations in galactic bars.

2023-06-09
11:00
Trace gases and weather: exoplanet atmospheres 
with JWST and the ELTs

Paul Molliere (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
With the recent launch of JWST, and with the ELT seeing first light towards the end of this decade, the exoplanet atmosphere community is in for an exciting ride. In this talk I will focus on two aspects of science enabled by these observatories. The first is tracing rare atmospheric absorbers, which have never been detected before. These allow us to constrain planet formation from a new angle, going beyond the often-mentioned carbon-to-oxygen number ratio. In addition, some of these detections allow us to probe atmospheric chemistry in disequilibrium, which had been a mostly theoretical exercise before JWST. As a part of this I will give a sneak peek of the results we obtain in the JWST MIRI GTO program. The second aspect is atmospheric weather: what can we learn about atmospheric variability and wind patterns with this new generation of observatories? I will discuss the observations that JWST is going to take in the near future, and what we can expect once the ELT comes online, revealing individual absorption lines in the atmospheres of extrasolar planets.

2023-06-09
11:00
TBD
Paul Molliere (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2023-06-09
11:00
Trace gases and weather: exoplanet atmospheres 
with JWST and the ELTs

Paul Molliere (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
With the recent launch of JWST, and with the ELT seeing first light towards the end of this decade, the exoplanet atmosphere community is in for an exciting ride. In this talk I will focus on two aspects of science enabled by these observatories. The first is tracing rare atmospheric absorbers, which have never been detected before. These allow us to constrain planet formation from a new angle, going beyond the often-mentioned carbon-to-oxygen number ratio. In addition, some of these detections allow us to probe atmospheric chemistry in disequilibrium, which had been a mostly theoretical exercise before JWST. As a part of this I will give a sneak peek of the results we obtain in the JWST MIRI GTO program. The second aspect is atmospheric weather: what can we learn about atmospheric variability and wind patterns with this new generation of observatories? I will discuss the observations that JWST is going to take in the near future, and what we can expect once the ELT comes online, revealing individual absorption lines in the atmospheres of extrasolar planets.

2023-06-02
11:00
TBD
José Eduardo Méndez Delgado (ARI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2023-06-02
11:00
Temperature inhomogeneities cause the abundance discrepancy in H II regions
José Eduardo Méndez Delgado (ARI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
H II regions, ionized nebulae associated to massive star formation, exhibit a wealth of emission lines that are the fundamental basis for estimating the chemical composition of the Universe. Heavy element abundances are particularly important because they regulate the cooling of the interstellar gas and are essential to the understanding of several phenomena such as nucleosynthesis, star formation and chemical evolution. For more than 80 years, however, a discrepancy of a factor of around two between heavy-element abundances derived with collisional excited lines (CELs) and recombination lines (RLs) has thrown our absolute abundance determinations into doubt.  The widely observed CELs are ~10,000 times brighter than RLs but exponentially dependent on temperature. Which of the lines (if any) gives the correct heavy-element abundances?
In this colloquium, I will talk about the solution we found for this problem, recently published in Nature. The best available deep optical spectra of star forming regions show evidence of the presence of temperature inhomogeneities within the gas. These inhomogeneities are concentrated in the highly ionized gas and cause the abundance discrepancy problem. This work implies that most metallicity determinations, those based on CELs, must be revised as they may be severely underestimated. The evidence indicates that this effect could be greater in regions of lower metallicity, such as the JWST high-z galaxies. Fortunately, since the temperature inhomogeneities are concentrated in the highly ionized areas of the nebulae, it is possible to correctly determine metallicities using CELs, following the proposed empirical relations.

2023-06-02
11:00
Temperature inhomogeneities cause the abundance discrepancy in H II regions
José Eduardo Méndez Delgado (ARI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
H II regions, ionized nebulae associated to massive star formation, exhibit a wealth of emission lines that are the fundamental basis for estimating the chemical composition of the Universe. Heavy element abundances are particularly important because they regulate the cooling of the interstellar gas and are essential to the understanding of several phenomena such as nucleosynthesis, star formation and chemical evolution. For more than 80 years, however, a discrepancy of a factor of around two between heavy-element abundances derived with collisional excited lines (CELs) and recombination lines (RLs) has thrown our absolute abundance determinations into doubt.  The widely observed CELs are ~10,000 times brighter than RLs but exponentially dependent on temperature. Which of the lines (if any) gives the correct heavy-element abundances?
In this colloquium, I will talk about the solution we found for this problem, recently published in Nature. The best available deep optical spectra of star forming regions show evidence of the presence of temperature inhomogeneities within the gas. These inhomogeneities are concentrated in the highly ionized gas and cause the abundance discrepancy problem. This work implies that most metallicity determinations, those based on CELs, must be revised as they may be severely underestimated. The evidence indicates that this effect could be greater in regions of lower metallicity, such as the JWST high-z galaxies. Fortunately, since the temperature inhomogeneities are concentrated in the highly ionized areas of the nebulae, it is possible to correctly determine metallicities using CELs, following the proposed empirical relations.

2023-05-26
11:00
The JWST view on ice and gas
Giulia Perotti (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The interaction between interstellar dust, ice and gas plays a major role for the chemistry in regions where star and planets form. Different reactions occur in the gas and on the ice mantles of dust grains in these regions, and consequently the mutual exchange of matter between the two phases is what regulates the physical and chemical evolution of newborn stars and planets. In this talk, I will introduce recent discoveries using JWST that are advancing our understanding of this complex interplay. I will show first JWST observations of the PDS 70 planet-forming disk as part of the MIRI mid-INfrared Disk Survey (MINDS, PI: Th. Henning). The much higher sensitivity of MIRI-MRS compared with previous Spitzer data reveals emission of water vapour. This demonstrates that the terrestrial planet-forming zone of PDS 70 has maintained to some degree the physical and chemical conditions of young disks, in spite of the ~65 AU planet-induced gap.

2023-05-26
11:00
The JWST view on ice and gas during star and planet formation
Giulia Perotti (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2023-05-12
11:00
TBD
Michael Küffmeier (MPE)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2023-05-12
11:00
Modeling constraints on the mass reservoirs of forming disks
Michael Küffmeier (MPE)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The traditional paradigm of star and planet formation can be summarized as follows: stars form with circumstellar disks due to the collapse of rotating dense gas and dust. Such disks are of existential importance as they are the birthplaces of planets. The colloquium will provide an overview of developments and challenges in modeling the formation of these disks that are often referred to as protoplanetary or planet-forming disks. First, I will summarize how various problems related to disk formation arose and were subsequently solved by incorporating various physical effects in spherical core collapse models during the last two decades. I will particularly focus on the effects of magnetic fields and the role of the ionization rate during the collapse phase. The latter is potentially more important for the diversity of disk sizes in various star-forming environments than currently recognized. Recent observations of so-called streamers that seem to feed the forming disk with fresh material are another sign that the protostellar environment plays a bigger role for disk and ultimately planet formation than we previously believed. In line with the picture of variable accretion, disks can be fed with fresh material at later stages or may even be entirely rejuvenated. Finally, I will highlight key implications of an onset of planet formation while disk formation is ongoing.

2023-05-12
11:00
Modeling constraints on the mass reservoirs of forming disks
Michael Küffmeier (MPE)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The traditional paradigm of star and planet formation can be summarized as follows: stars form with circumstellar disks due to the collapse of rotating dense gas and dust. Such disks are of existential importance as they are the birthplaces of planets. The colloquium will provide an overview of developments and challenges in modeling the formation of these disks that are often referred to as protoplanetary or planet-forming disks. First, I will summarize how various problems related to disk formation arose and were subsequently solved by incorporating various physical effects in spherical core collapse models during the last two decades. I will particularly focus on the effects of magnetic fields and the role of the ionization rate during the collapse phase. The latter is potentially more important for the diversity of disk sizes in various star-forming environments than currently recognized. Recent observations of so-called streamers that seem to feed the forming disk with fresh material are another sign that the protostellar environment plays a bigger role for disk and ultimately planet formation than we previously believed. In line with the picture of variable accretion, disks can be fed with fresh material at later stages or may even be entirely rejuvenated. Finally, I will highlight key implications of an onset of planet formation while disk formation is ongoing.

2023-05-05
11:00
Non-ideal MHD simulations of astrophysical jets with the PLUTO code
Giancarlo Mattia (Arcetri)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Astrophysical jets, consisting of collimated high-speed outflows, are typically found in several sources, e.g., young stellar objects, X-ray binaries, gamma-ray bursts, or active galactic nuclei. The formation of collimated outflows requires some common features, such as the presence of a central object, an accretion disk and a large scale magnetic field (whose origin is still unclear). At first I will discuss dynamo processes within thin accretion disks, able to amplify the magnetic field up to the point where the launching becomes possible, focusing on how to build a more consistent dynamo and diffusivity model. Then I will discuss the first numerical simulations of resistive relativistic jets and the role of magnetic reconnection in the large-scale simulations, which may be responsible for particles acceleration in astrophysical outflows.

2023-05-05
11:00
Non-ideal MHD simulations of astrophysical jets with the PLUTO code
Giancarlo Mattia (Arcetri)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Astrophysical jets, consisting of collimated high-speed outflows, are typically found in several sources, e.g., young stellar objects, X-ray binaries, gamma-ray bursts, or active galactic nuclei. The formation of collimated outflows requires some common features, such as the presence of a central object, an accretion disk and a large scale magnetic field (whose origin is still unclear). At first I will discuss dynamo processes within thin accretion disks, able to amplify the magnetic field up to the point where the launching becomes possible, focusing on how to build a more consistent dynamo and diffusivity model. Then I will discuss the first numerical simulations of resistive relativistic jets and the role of magnetic reconnection in the large-scale simulations, which may be responsible for particles acceleration in astrophysical outflows.

2023-05-05
11:00
Non-ideal MHD simulations of astrophysical jets with the PLUTO code
Giancarlo Mattia (Arcetri)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Astrophysical jets, consisting of collimated high-speed outflows, are typically found in several sources, e.g., young stellar objects, X-ray binaries, gamma-ray bursts, or active galactic nuclei. The formation of collimated outflows requires some common features, such as the presence of a central object, an accretion disk and a large scale magnetic field (whose origin is still unclear). At first I will discuss dynamo processes within thin accretion disks, able to amplify the magnetic field up to the point where the launching becomes possible, focusing on how to build a more consistent dynamo and diffusivity model. Then I will discuss the first numerical simulations of resistive relativistic jets and the role of magnetic reconnection in the large-scale simulations, which may be responsible for particles acceleration in astrophysical outflows.

2023-04-21
11:00
LYRA: Pioneering the realm of ultra-high resolution galaxy formation simulations
Thales Gutcke (Uni of Hawaii)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
One of the greatest uncertainties in current cosmological simulations is the effects of baryonic feedback, since current effective models lack predictability. I will introduce LYRA, a novel cosmological galaxy formation model using moving mesh hydrodynamics that resolves every single supernova and the resulting outflows from first principles. To accomplish this, the simulation is run at ultra-high resolution, includes a multi-phase interstellar medium, individual stars, resolved supernova cooling radii and inhomogeneous metal seeding by Population III stars. The model is run to z=0 on a set of field dwarf galaxies that match the stellar mass, size, stellar kinematics and metallicity relations of Local Group dwarf spheroidals. I proceed to describe the star formation histories, the high redshift assembly, the enriched outflows that contribute to the metal pollution of the intergalactic medium and the present-day globular cluster-like substructure. I show that ultra-high resolution simulations go beyond merely providing more spatial information on smaller scales. Instead, penetrating this regime unfolds access to an emergent set of small-scale constraints on galaxy formation.

2023-04-21
11:00
LYRA: Pioneering the realm of ultra-high resolution galaxy formation simulations
Thales Gutcke (Uni of Hawaii)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
One of the greatest uncertainties in current cosmological simulations is the effects of baryonic feedback, since current effective models lack predictability. I will introduce LYRA, a novel cosmological galaxy formation model using moving mesh hydrodynamics that resolves every single supernova and the resulting outflows from first principles. To accomplish this, the simulation is run at ultra-high resolution, includes a multi-phase interstellar medium, individual stars, resolved supernova cooling radii and inhomogeneous metal seeding by Population III stars. The model is run to z=0 on a set of field dwarf galaxies that match the stellar mass, size, stellar kinematics and metallicity relations of Local Group dwarf spheroidals. I proceed to describe the star formation histories, the high redshift assembly, the enriched outflows that contribute to the metal pollution of the intergalactic medium and the present-day globular cluster-like substructure. I show that ultra-high resolution simulations go beyond merely providing more spatial information on smaller scales. Instead, penetrating this regime unfolds access to an emergent set of small-scale constraints on galaxy formation.

2023-04-21
11:00
LYRA: Pioneering the realm of ultra-high resolution galaxy formation simulations
Thales Gutcke (Uni of Hawaii)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
One of the greatest uncertainties in current cosmological simulations is the effects of baryonic feedback, since current effective models lack predictability. I will introduce LYRA, a novel cosmological galaxy formation model using moving mesh hydrodynamics that resolves every single supernova and the resulting outflows from first principles. To accomplish this, the simulation is run at ultra-high resolution, includes a multi-phase interstellar medium, individual stars, resolved supernova cooling radii and inhomogeneous metal seeding by Population III stars. The model is run to z=0 on a set of field dwarf galaxies that match the stellar mass, size, stellar kinematics and metallicity relations of Local Group dwarf spheroidals. I proceed to describe the star formation histories, the high redshift assembly, the enriched outflows that contribute to the metal pollution of the intergalactic medium and the present-day globular cluster-like substructure. I show that ultra-high resolution simulations go beyond merely providing more spatial information on smaller scales. Instead, penetrating this regime unfolds access to an emergent set of small-scale constraints on galaxy formation.

2023-04-14
11:00
Andromeda as a Stepping Stone to the Local Volume: Resolved Stellar Chemodynamics of Extragalactic Streams, Shells, and Disks
Ivanna Escala (Princeton U.)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The formation histories of massive disk galaxies are key to understanding galactic hierarchical assembly and matter distributions. Within the Local Group, Andromeda (M31) provides a unique opportunity for detailed reconstructions of galaxy formation history, where its active merger history sets it apart from the Milky Way (MW). Two primary outstanding questions remain concerning M31's assembly history:  has its disk survived a major merger within the last few billion years, and does this major merger coincide with the formation of M31's Giant Stellar Stream (GSS) and its various tidal shells? In this talk, I will present results from the Elemental Abundances in M31 and Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo (SPLASH) surveys on resolved stellar chemodynamics in M31's disk region and GSS-related tidal substructure. I will discuss implications for the formation of M31's disk and inner stellar halo and constraints on the nature of M31's last significant merger.  I will conclude by highlighting the utility of modern spectroscopic studies of resolved stellar populations in M31 for connecting our MW-based understanding of galaxy formation to future observations of disk galaxies in the Local Volume.

2023-04-14
11:00
Andromeda as a Stepping Stone to the Local Volume: Resolved Stellar Chemodynamics of Extragalactic Streams, Shells, and Disks
Ivanna Escala (Princeton U.)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The formation histories of massive disk galaxies are key to understanding galactic hierarchical assembly and matter distributions. Within the Local Group, Andromeda (M31) provides a unique opportunity for detailed reconstructions of galaxy formation history, where its active merger history sets it apart from the Milky Way (MW). Two primary outstanding questions remain concerning M31's assembly history:  has its disk survived a major merger within the last few billion years, and does this major merger coincide with the formation of M31's Giant Stellar Stream (GSS) and its various tidal shells? In this talk, I will present results from the Elemental Abundances in M31 and Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo (SPLASH) surveys on resolved stellar chemodynamics in M31's disk region and GSS-related tidal substructure. I will discuss implications for the formation of M31's disk and inner stellar halo and constraints on the nature of M31's last significant merger.  I will conclude by highlighting the utility of modern spectroscopic studies of resolved stellar populations in M31 for connecting our MW-based understanding of galaxy formation to future observations of disk galaxies in the Local Volume.

2023-04-14
11:00
Andromeda as a Stepping Stone to the Local Volume: Resolved Stellar Chemodynamics of Extragalactic Streams, Shells, and Disks
Ivanna Escala (Princeton U.)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The formation histories of massive disk galaxies are key to understanding galactic hierarchical assembly and matter distributions. Within the Local Group, Andromeda (M31) provides a unique opportunity for detailed reconstructions of galaxy formation history, where its active merger history sets it apart from the Milky Way (MW). Two primary outstanding questions remain concerning M31's assembly history:  has its disk survived a major merger within the last few billion years, and does this major merger coincide with the formation of M31's Giant Stellar Stream (GSS) and its various tidal shells? In this talk, I will present results from the Elemental Abundances in M31 and Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo (SPLASH) surveys on resolved stellar chemodynamics in M31's disk region and GSS-related tidal substructure. I will discuss implications for the formation of M31's disk and inner stellar halo and constraints on the nature of M31's last significant merger.  I will conclude by highlighting the utility of modern spectroscopic studies of resolved stellar populations in M31 for connecting our MW-based understanding of galaxy formation to future observations of disk galaxies in the Local Volume.

2023-03-31
11:00
TBA
Ivanna Escala (Princeton U.)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2023-03-24
11:00
Predictions for the faint Lyman-alpha cosmic web
Chris Byrohl (ZAH/ITA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Neutral hydrogen in the filaments of the cosmic web may be observable through emission of the Lyman-alpha line. Although luminous Lyman-alpha emitters are already an established tracer of the matter distribution in the high-redshift universe, the implications of the faint Lyman-alpha glow within the cosmic web, away from luminous emitters, are yet to be explored. In this talk, I will discuss the nature of large-scale, diffuse Lyman-alpha filaments and their detectability with recent integral field spectrographs such as VLT-MUSE, K-CWI, and HET-VIRUS. To explore this, we combine recent cosmological magnetohydrodynamical galaxy formation simulations with explicit calculation of the Lyman-alpha radiative transfer. We find that observable filaments are illuminated by Lyman-alpha photons that are emitted from the circumgalactic medium of intermediate-mass halos, rather than from the filaments themselves. These photons then escape and scatter within their surrounding, substantially boosting the Lyman-alpha signal from diffuse filaments. Our work provides a reference model for Lyman-alpha filaments, and demonstrates the importance and complexities of Lyman-alpha radiative transfer across spatial scales.

2023-03-17
11:00
Rapid accretion of rocky planets and the outgassing of their first atmospheres
Anders Johansen (The Globe Institute)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Terrestrial planets have traditionally been thought to form by collisions between protoplanets taking place mostly after the dissipation of the protoplanetary disc, on time-scales of 30-100 million years. I present here a new theoretical model where terrestrial planets grow instead by accreting small pebbles in the protoplanetary disc within 3-5 million years. I discuss how the immense pebble accretion heat leads to extensive melting of the growing planets and to the emergence of deep magma oceans. Volatiles such as water, carbon and nitrogen are accreted with the pebbles and partitioned between atmosphere, magma ocean and core. The end of the accretion phase leads to rapid crystallisation of the magma ocean and outgassing of the first atmosphere. I will show how the atmospheric composition of young planets is key to understanding the origin of life.

2023-03-17
11:00
Rapid accretion of rocky planets and the outgassing of their first atmospheres
Anders Johansen (The Globe Institute)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Terrestrial planets have traditionally been thought to form by collisions between protoplanets taking place mostly after the dissipation of the protoplanetary disc, on time-scales of 30-100 million years. I present here a new theoretical model where terrestrial planets grow instead by accreting small pebbles in the protoplanetary disc within 3-5 million years. I discuss how the immense pebble accretion heat leads to extensive melting of the growing planets and to the emergence of deep magma oceans. Volatiles such as water, carbon and nitrogen are accreted with the pebbles and partitioned between atmosphere, magma ocean and core. The end of the accretion phase leads to rapid crystallisation of the magma ocean and outgassing of the first atmosphere. I will show how the atmospheric composition of young planets is key to understanding the origin of life.

2023-03-10
11:00
Modeling disks and jets around forming massive stars
Andre Oliva (Uni Heidelberg)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
During their early formation stages, massive stars are surrounded by accretion disks and launch powerful magnetically-driven jets and molecular outflows. The tteoretical modeling of such system poses significant challenges due to the wide range of scales and physical effects involved. Observing the innermost (embedded) material surrounding a forming massive star has only been possible recently, thanks to the use of techniques like very-long-baseline interferometry (VLBI). In this talk, I will offer a tour through simulations of massive star formation from a collapsing cloud, with emphasis on the fragmentation of accretion disks and the launch of protostellar jets. I will discuss how high spatial resolution is helping us to understand the formation of massive stellar multiple systems via disk fragmentation. Finally, I will show how a new generation of observations and simulations have come together to uncover the physics of launching protostellar jets.

2023-03-10
11:00
Modeling disks and jets around forming massive stars
Andre Oliva (Uni Heidelberg)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
During their early formation stages, massive stars are surrounded by accretion disks and launch powerful magnetically-driven jets and molecular outflows. The tteoretical modeling of such system poses significant challenges due to the wide range of scales and physical effects involved. Observing the innermost (embedded) material surrounding a forming massive star has only been possible recently, thanks to the use of techniques like very-long-baseline interferometry (VLBI). In this talk, I will offer a tour through simulations of massive star formation from a collapsing cloud, with emphasis on the fragmentation of accretion disks and the launch of protostellar jets. I will discuss how high spatial resolution is helping us to understand the formation of massive stellar multiple systems via disk fragmentation. Finally, I will show how a new generation of observations and simulations have come together to uncover the physics of launching protostellar jets.

2023-03-03
11:00
The JWST view on ice and gas
Giulia Perotti (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The interaction between interstellar dust, ice and gas plays a major role for the chemistry in regions where star and planets form. Different reactions occur in the gas and on the ice mantles of dust grains in these regions, and consequently the mutual exchange of matter between the two phases is what regulates the physical and chemical evolution of newborn stars and planets. In this talk, I will introduce recent discoveries using JWST that are advancing our understanding of this complex interplay. I will show first JWST observations of the PDS 70 planet-forming disk as part of the MIRI mid-INfrared Disk Survey (MINDS, PI: Th. Henning). The much higher sensitivity of MIRI-MRS compared with previous Spitzer data reveals emission of water vapour. This demonstrates that the terrestrial planet-forming zone of PDS 70 has maintained to some degree the physical and chemical conditions of young disks, in spite of the ~65 AU planet-induced gap.

2023-02-24
11:00
Astrochemistry: From disks to planets & moons
Inga Kamp (Kapteyn Astronomical Institute)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
In the past 20 years, new facilities such as the VLT and ALMA allowed us to spatially resolve planet forming disks and to understand the distribution and composition of the material that builds the planets and potentially moons around them. The exquisite data that we obtain from such facilities provides a top level overview of the process of planet formation, but also allows us to understand the detailed physics and chemistry at play in specific environments. Radiative transfer thermo-chemical disk models are ideal virtual laboratories to explore the complex interplay between dust and gas in disks and how this can affect and/or change our interpretation of observations. I will also show how such disk models can give novel insights into characterizing the planet and moon forming processes.

2023-02-24
11:00
Astrochemistry: From disks to planets & moons
Inga Kamp (Kapteyn Astronomical Institute)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
In the past 20 years, new facilities such as the VLT and ALMA allowed us to spatially resolve planet forming disks and to understand the distribution and composition of the material that builds the planets and potentially moons around them. The exquisite data that we obtain from such facilities provides a top level overview of the process of planet formation, but also allows us to understand the detailed physics and chemistry at play in specific environments. Radiative transfer thermo-chemical disk models are ideal virtual laboratories to explore the complex interplay between dust and gas in disks and how this can affect and/or change our interpretation of observations. I will also show how such disk models can give novel insights into characterizing the planet and moon forming processes.

2023-02-17
11:00
TBA
Giulia Perotti (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2023-02-17
11:00
TBA
Chris Byrohl (ZAH/ITA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2023-02-17
11:00
A new national institute for astronomical research: DZA (Deutsches Zentrum für Astrophysik)
Stefan Wagner (ZAH/LSW)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
In September 2022 the German federal ministry for research launched a new national institute for astronomical research. The DZA (Deutsches Zentrum für Astrophysik) will be based in Görlitz, Saxony, and shall enter a start-up phase in spring 2023. It is intended to support astrophysical research in Germany and implements a long-held vision of the astronomical community. Following a three-year preparatory period, the center will conduct research and provide services in technology, data science and astrophysics. A special focus shall be placed on interdisciplinary synergies.
In this seminar the motivation and rationale of the proposal that had been selected for implementation will be described along with the political and financial constraints and opportunities. During the preparatory period the strategy for the first decade shall be detailed with further community involvement. Current plans will be presented.

2023-02-17
11:00
A new national institute for astronomical research: DZA (Deutsches Zentrum für Astrophysik)
Stefan Wagner (ZAH/LSW)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
In September 2022 the German federal ministry for research launched a new national institute for astronomical research. The DZA (Deutsches Zentrum für Astrophysik) will be based in Görlitz, Saxony, and shall enter a start-up phase in spring 2023. It is intended to support astrophysical research in Germany and implements a long-held vision of the astronomical community. Following a three-year preparatory period, the center will conduct research and provide services in technology, data science and astrophysics. A special focus shall be placed on interdisciplinary synergies.
In this seminar the motivation and rationale of the proposal that had been selected for implementation will be described along with the political and financial constraints and opportunities. During the preparatory period the strategy for the first decade shall be detailed with further community involvement. Current plans will be presented.

2023-02-10
15:00
The First Astronomers: How Indigenous Elders Read the Stars
Duane Hamacher (Melbourne)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Indigenous Elders of the world are expert observers of the stars. They teach that everything on the land is reflected in the sky, and everything in the sky is reflected on the land. These living systems of knowledge challenge conventional ideas about the nature of science and the longevity of oral tradition. This talk will explore the scientific layers of Australian Indigenous star knowledge with a focus on observations of variable stars, cataclysmic stars, stellar scintillation, the motions of planets, and transient phenomena, showing how this can guide modern scientific research.

2023-02-10
15:00
The First Astronomers: How Indigenous Elders Read the Stars
Duane Hamacher (Melbourne)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Indigenous Elders of the world are expert observers of the stars. They teach that everything on the land is reflected in the sky, and everything in the sky is reflected on the land. These living systems of knowledge challenge conventional ideas about the nature of science and the longevity of oral tradition. This talk will explore the scientific layers of Australian Indigenous star knowledge with a focus on observations of variable stars, cataclysmic stars, stellar scintillation, the motions of planets, and transient phenomena, showing how this can guide modern scientific research.

2023-02-10
11:00
The First Astronomers: How Indigenous Elders Read the Stars
Duane Hamacher (Melbourne)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Indigenous Elders of the world are expert observers of the stars. They teach that everything on the land is reflected in the sky, and everything in the sky is reflected on the land. These living systems of knowledge challenge conventional ideas about the nature of science and the longevity of oral tradition. This talk will explore the scientific layers of Australian Indigenous star knowledge with a focus on observations of variable stars, cataclysmic stars, stellar scintillation, the motions of planets, and transient phenomena, showing how this can guide modern scientific research.

2023-02-03
11:00
From the Galaxy to Stars: Galactic Multi-scale Simulations of GMC and Star Cluster Formation
Ralph Pudritz (McMaster)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The advent of ALMA, JWST, and a host of recent high resolution atomic hydrogen, molecular gas, and dust surveys are transforming our understanding of star formation over a very wide range of physical scales. From large scale kpc filaments and superbubble structures, to giant molecular clouds (GMCs) on 100 pc scales, star clusters (1 pc) and the sub pc scale filaments in which we observe individual stars form, a new hierarchical and dynamic picture of star formation is emerging. I will review recent progress in simulations and theory of star formation that addresses the physical connections between structure formation from the galactic to pc scales. I will then discuss our own recent galactic multi-scale, zoom-in simulations that allows us to track the formation of structure from galactic to sub pc scales in a magnetized, Milky Way like galaxy undergoing supernova driven feedback processes. A wide variety of structures including superbubbles, kpc atomic gas filaments, smaller scale filamentary GMCs, and star cluster regions form. Gravitational instability of filaments on these different scales and filamentary flows within them, drive GMC and cluster formation respectively. In quieter regions, galactic shear can produce filamentary GMCs within flattened, rotating disk-like structures on 100 pc scales. Strikingly, magnetic field topologies associated with such disk structures are highly helical. This variety seems to reflect recent observational 3D structure maps of nearby GMCs.

2023-02-03
11:00
From the Galaxy to Stars: Galactic Multi-scale Simulations of GMC and Star Cluster Formation
Ralph Pudritz (McMaster)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The advent of ALMA, JWST, and a host of recent high resolution atomic hydrogen, molecular gas, and dust surveys are transforming our understanding of star formation over a very wide range of physical scales. From large scale kpc filaments and superbubble structures, to giant molecular clouds (GMCs) on 100 pc scales, star clusters (1 pc) and the sub pc scale filaments in which we observe individual stars form, a new hierarchical and dynamic picture of star formation is emerging. I will review recent progress in simulations and theory of star formation that addresses the physical connections between structure formation from the galactic to pc scales. I will then discuss our own recent galactic multi-scale, zoom-in simulations that allows us to track the formation of structure from galactic to sub pc scales in a magnetized, Milky Way like galaxy undergoing supernova driven feedback processes. A wide variety of structures including superbubbles, kpc atomic gas filaments, smaller scale filamentary GMCs, and star cluster regions form. Gravitational instability of filaments on these different scales and filamentary flows within them, drive GMC and cluster formation respectively. In quieter regions, galactic shear can produce filamentary GMCs within flattened, rotating disk-like structures on 100 pc scales. Strikingly, magnetic field topologies associated with such disk structures are highly helical. This variety seems to reflect recent observational 3D structure maps of nearby GMCs.

2023-01-27
11:00
Galactic and extra-galactic chemical evolution probed by SDSS
Jianhui Lian (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Galaxy chemical evolution is regulated by the interplay between galaxy internal star formation and external matter exchange with the environment (i.e. gas accretion and outflow winds). Therefore, studying galactic chemical evolution is an important way to uncover the roles played by these processes in driving galaxy formation and evolution. Sloan Digital Sky Survey (SDSS) have collected tremendous spectroscopic chemistry observations for stars in the Milky Way as well as stellar populations and ionised gas in external galaxies, which serves as ideal dataset to study galaxy chemical evolution. In this talk, I will introduce my previous works using SDSS data on both galactic and extra-galactic chemical evolution. At the end of the talk, I will share my own prospect on the future galactic/stellar chemistry studies in terms of linking the Galactic and extragalactic observations.

2023-01-27
11:00
Galactic and extra-galactic chemical evolution probed by SDSS
Jianhui Lian (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Galaxy chemical evolution is regulated by the interplay between galaxy internal star formation and external matter exchange with the environment (i.e. gas accretion and outflow winds). Therefore, studying galactic chemical evolution is an important way to uncover the roles played by these processes in driving galaxy formation and evolution. Sloan Digital Sky Survey (SDSS) have collected tremendous spectroscopic chemistry observations for stars in the Milky Way as well as stellar populations and ionised gas in external galaxies, which serves as ideal dataset to study galaxy chemical evolution. In this talk, I will introduce my previous works using SDSS data on both galactic and extra-galactic chemical evolution. At the end of the talk, I will share my own prospect on the future galactic/stellar chemistry studies in terms of linking the Galactic and extragalactic observations.

2023-01-20
11:00
Star Clusters: Constraining Gas Clearing Timescales with HST Hα Imaging and Classifying Cluster Morphology with Machine Learning
Stephen Hannon (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The analysis of star cluster ages in tandem with the detailed morphology of any associated HII regions can provide insight into the processes that clear a cluster's natal gas, as well as the accuracy of cluster ages and dust extinction derived from Spectral Energy Distribution (SED) fitting. We classify 3757 star clusters in 16 nearby (D < 10 Mpc) galaxies according to their H? morphology (concentrated, partially exposed, no emission), using HST imaging from LEGUS. Briefly, we find a relatively early onset of gas clearing and a short (1-2 Myr) clearing timescale, regardless of distance-dependent resolution effects. We also note issues between SED fitting and the age-extinction degeneracy for low-mass clusters (due to stochastic sampling effects) as well as for some massive, globular clusters, however these do not affect our reported timescales.

Additionally, the time required to produce human-inspected cluster catalogs such as those used in the above study has limited the availability of star cluster samples. To greatly expand upon these samples, deep learning models have recently been proven capable of classifying star clusters at production-scale for nearby spiral galaxies (D < 20 Mpc). In order to optimize the reliability of such models, we use HST UV-optical imaging of objects from the PHANGS-HST survey to create updated models and investigate methods of improving their performance.

2023-01-20
11:00
Star Clusters: Constraining Gas Clearing Timescales with HST Hα Imaging and Classifying Cluster Morphology with Machine Learning
Stephen Hannon (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The analysis of star cluster ages in tandem with the detailed morphology of any associated HII regions can provide insight into the processes that clear a cluster's natal gas, as well as the accuracy of cluster ages and dust extinction derived from Spectral Energy Distribution (SED) fitting. We classify 3757 star clusters in 16 nearby (D < 10 Mpc) galaxies according to their H? morphology (concentrated, partially exposed, no emission), using HST imaging from LEGUS. Briefly, we find a relatively early onset of gas clearing and a short (1-2 Myr) clearing timescale, regardless of distance-dependent resolution effects. We also note issues between SED fitting and the age-extinction degeneracy for low-mass clusters (due to stochastic sampling effects) as well as for some massive, globular clusters, however these do not affect our reported timescales.

Additionally, the time required to produce human-inspected cluster catalogs such as those used in the above study has limited the availability of star cluster samples. To greatly expand upon these samples, deep learning models have recently been proven capable of classifying star clusters at production-scale for nearby spiral galaxies (D < 20 Mpc). In order to optimize the reliability of such models, we use HST UV-optical imaging of objects from the PHANGS-HST survey to create updated models and investigate methods of improving their performance.

2023-01-13
11:00
SPHERE+ an Upgrade for the VLT's Planet Finder Instrument
Markus Feldt (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The VLT's planet finder instrument SPHERE has been in operation for 7 years now, and has generated hundreds of papers and has greatly changed our understanding of how planets form.  It does, however, have its limitation, a couple of which have been identified, and ways have been proposed to overcome them.  I will introduce you to the SPHERE+ project, which aims at improving SPHERE's planet detection capabilities further. I will detail the proposed modifications and their predicted impact on SPHERE's performance.  I will also briefly talk about the somewhat unusual organization of the project, the proposed timeline and funding, and the role of MPIA.  I will round off the last point with a brief history of MPIA's involvement in SPHERE, and in other key adaptive optics projects during the past decades.

2023-01-13
11:00
SPHERE+ an Upgrade for the VLT's Planet Finder Instrument
Markus Feldt (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The VLT's planet finder instrument SPHERE has been in operation for 7 years now, and has generated hundreds of papers and has greatly changed our understanding of how planets form.  It does, however, have its limitation, a couple of which have been identified, and ways have been proposed to overcome them.  I will introduce you to the SPHERE+ project, which aims at improving SPHERE's planet detection capabilities further. I will detail the proposed modifications and their predicted impact on SPHERE's performance.  I will also briefly talk about the somewhat unusual organization of the project, the proposed timeline and funding, and the role of MPIA.  I will round off the last point with a brief history of MPIA's involvement in SPHERE, and in other key adaptive optics projects during the past decades.

2022-12-15
14:00
The 3D structure of the Milky Way and its Molecular Clouds in the era of Gaia
:Thavisha Dharmawardena (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The detailed 3D distributions of dust density and extinction in the Milky Way have long been sought after. However, such 3D reconstruction from sparse data is non-trivial but is essential to understanding the properties of star formation, large-scale dynamics, and structure of our Galaxy. In this talk, I will introduce our new fast and scalable algorithm for 3D dust modeling, DUSTRIBUTION. Using advanced ML methods such as sparse Gaussian Processes and Variational Inference, our algorithm maps Star Formation Regions (SFRs) with millions of input sources in parsec scales within an hour on a single GPU. Our approach allows us to identify large-scale structures in star-formation regions while simultaneously peering into individual molecular clouds, providing insights into multi-scale processes such as fragmentation in molecular clouds.

In Dharmawardena et al., 2022a and b, we model the 3D dust density distribution of 16 SFRs, exploiting distances and extinctions derived from Gaia DR2 and IR data (from Fouesneau et al., 2022). From these maps, we extract 3D boundaries, volumes, precise dust masses (12% statistical uncertainty), and filling factors to study fragmentation within our regions. We recover a more comprehensive range of substructures, such as new interconnecting, free-standing filaments, star-formation feedback, and supernovae cavities. Our sample spans a wide range of environments and masses which we use to explore the variation of these parameters and their environmental effects. For example, we show that, contrary to previous suggestions, the California molecular cloud, while being more massive, is much more extended and hence more diffuse than Orion A, explaining its lower star-formation rate. We also find that Vela C exhibits a significant distance gradient along the cloud and is the most massive component of the Vela Molecular Ridge. We demonstrate it is necessary to clearly define boundaries in 3D for these clouds to determine their masses accurately. Integrating the extinction over the complete line of sight overestimates the mass over an order of magnitude. Compared to Planck data, we demonstrate for the first time that the known relationships between density and dust processing, where high-extinction lines-of-sight have the most processed grains, hold up in resolved observations and continue on more minor scales than previously suggested. In ongoing work, we map the complete Milky Way out to 3 kpc using Gaia data, recovering the dense regions of molecular clouds simultaneously along with larger-scale structures.

Finally, I will showcase our work done in collaboration with the HdA to visualize these data sets in 3D using several techniques, including on the planetarium dome and augmented reality.

2022-12-15
14:00
The 3D structure of the Milky Way and its Molecular Clouds in the era of Gaia
:Thavisha Dharmawardena (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The detailed 3D distributions of dust density and extinction in the Milky Way have long been sought after. However, such 3D reconstruction from sparse data is non-trivial but is essential to understanding the properties of star formation, large-scale dynamics, and structure of our Galaxy. In this talk, I will introduce our new fast and scalable algorithm for 3D dust modeling, DUSTRIBUTION. Using advanced ML methods such as sparse Gaussian Processes and Variational Inference, our algorithm maps Star Formation Regions (SFRs) with millions of input sources in parsec scales within an hour on a single GPU. Our approach allows us to identify large-scale structures in star-formation regions while simultaneously peering into individual molecular clouds, providing insights into multi-scale processes such as fragmentation in molecular clouds.

In Dharmawardena et al., 2022a and b, we model the 3D dust density distribution of 16 SFRs, exploiting distances and extinctions derived from Gaia DR2 and IR data (from Fouesneau et al., 2022). From these maps, we extract 3D boundaries, volumes, precise dust masses (12% statistical uncertainty), and filling factors to study fragmentation within our regions. We recover a more comprehensive range of substructures, such as new interconnecting, free-standing filaments, star-formation feedback, and supernovae cavities. Our sample spans a wide range of environments and masses which we use to explore the variation of these parameters and their environmental effects. For example, we show that, contrary to previous suggestions, the California molecular cloud, while being more massive, is much more extended and hence more diffuse than Orion A, explaining its lower star-formation rate. We also find that Vela C exhibits a significant distance gradient along the cloud and is the most massive component of the Vela Molecular Ridge. We demonstrate it is necessary to clearly define boundaries in 3D for these clouds to determine their masses accurately. Integrating the extinction over the complete line of sight overestimates the mass over an order of magnitude. Compared to Planck data, we demonstrate for the first time that the known relationships between density and dust processing, where high-extinction lines-of-sight have the most processed grains, hold up in resolved observations and continue on more minor scales than previously suggested. In ongoing work, we map the complete Milky Way out to 3 kpc using Gaia data, recovering the dense regions of molecular clouds simultaneously along with larger-scale structures.

Finally, I will showcase our work done in collaboration with the HdA to visualize these data sets in 3D using several techniques, including on the planetarium dome and augmented reality.

2022-12-09
11:00
TBD
HHSF2022
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2022-12-09
11:00
a story
Sarah Jeffreson (CfA) : From short-lived H2 molecules to powerful feedback-driven galactic winds
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The spatial distribution and clustering of stellar feedback across galaxy discs is a key driver of galactic outflows and therefore galaxy evolution. Using a suite of high-resolution isolated galaxy simulations spanning the star-forming main sequence, I will show that clustered supernova explosions are accounted for by spatially- and temporally-coherent star formation occurring in the most massive molecular clouds. These massive molecular clouds are sustained by the constant accretion of new dense gas from the surrounding environment, in competition with the constant ejection of gas by the momentum associated with the expanding ionised regions around young massive stars. By parametrising the gas accretion rate in terms of properties of the large-scale galactic environment, I will discuss how the detailed spatial distribution of star formation and stellar feedback could be modelled as a sub-grid process in future cosmological simulations.

2022-12-09
11:00
TBD
HHSF2022
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2022-12-09
11:00
a story
Sarah Jeffreson (CfA) : From short-lived H2 molecules to powerful feedback-driven galactic winds
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The spatial distribution and clustering of stellar feedback across galaxy discs is a key driver of galactic outflows and therefore galaxy evolution. Using a suite of high-resolution isolated galaxy simulations spanning the star-forming main sequence, I will show that clustered supernova explosions are accounted for by spatially- and temporally-coherent star formation occurring in the most massive molecular clouds. These massive molecular clouds are sustained by the constant accretion of new dense gas from the surrounding environment, in competition with the constant ejection of gas by the momentum associated with the expanding ionised regions around young massive stars. By parametrising the gas accretion rate in terms of properties of the large-scale galactic environment, I will discuss how the detailed spatial distribution of star formation and stellar feedback could be modelled as a sub-grid process in future cosmological simulations.

2022-12-02
11:00
Towards molecular complexity
Thomas Henning (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The Kepler and TESS missions together with radial-velocity observations from the ground revealed that low-mass planets are frequent. A number of rocky planets have been discovered in the habitable zone around their host stars. The next big challenge is to understand the transition of terrestrial planets from geochemical systems to biogeochemical worlds. The talk will introduce the main origins of life concepts. It will discuss how molecular complexity can be reached. In addition, it will introduce the new MPIA labs and will show first results.

2022-12-02
11:00
Towards molecular complexity
Thomas Henning (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2022-12-02
11:00
Towards molecular complexity
Thomas Henning (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The Kepler and TESS missions together with radial-velocity observations from the ground revealed that low-mass planets are frequent. A number of rocky planets have been discovered in the habitable zone around their host stars. The next big challenge is to understand the transition of terrestrial planets from geochemical systems to biogeochemical worlds. The talk will introduce the main origins of life concepts. It will discuss how molecular complexity can be reached. In addition, it will introduce the new MPIA labs and will show first results.

2022-11-25
15:00
Award celebration
Patzer colloquium
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Different time slot at 3PM.

2022-11-25
15:00
Award celebration
Patzer colloquium
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Different time slot at 3PM.

2022-11-25
11:00
Award celebration
Patzer colloquium
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
The award winner will present their work.

2022-11-25
11:00
Award celebration
Patzer colloquium
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
The award winner will present their work.

2022-11-25
11:00
Award celebration
Patzer colloquium
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
The award winner will present their work.

2022-11-25
11:00
Award celebration
Patzer colloquium
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
The award winner will present their work.

2022-11-18
11:00
Unveiling the complexities of massive star clusters
Richard de Grijs (Macquarie U.)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Around the turn of the last century, star clusters of all kinds were considered ‘simple' stellar populations. Over the past decade, this situation has changed dramatically. At the same time, star clusters are among the brightest stellar population components and, as such, they are visible out to much greater distances than individual stars, even the brightest, so that understanding the intricacies of star cluster composition and their evolution is imperative for understanding stellar populations and the evolution of galaxies as a whole. In this review of where the field has moved to in recent years, we place particular emphasis on the properties and importance of the effects of rapid stellar rotation, and the presence of multiplicity among the red-giant-branch populations in Magellanic Cloud star clusters with ages up to a few billion years.

2022-11-18
11:00
Unveiling the complexities of massive star clusters
Richard de Grijs (Macquarie U.)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Around the turn of the last century, star clusters of all kinds were considered ‘simple' stellar populations. Over the past decade, this situation has changed dramatically. At the same time, star clusters are among the brightest stellar population components and, as such, they are visible out to much greater distances than individual stars, even the brightest, so that understanding the intricacies of star cluster composition and their evolution is imperative for understanding stellar populations and the evolution of galaxies as a whole. In this review of where the field has moved to in recent years, we place particular emphasis on the properties and importance of the effects of rapid stellar rotation, and the presence of multiplicity among the red-giant-branch populations in Magellanic Cloud star clusters with ages up to a few billion years.

2022-11-11
11:00
Is the Stellar Initial Mass Function Truly Universal?
Charles Steinhardt (DAWN)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Current techniques for analyzing large photometric catalogs are generally forced to assume a single, universal stellar initial mass function (IMF), although the IMF should be expected to vary depending upon conditions within a star-forming galaxy. The introduction of an additional parameter into photometric template fitting allows galaxies to be fit with a range of different IMFs. Most galaxies are best fit with a bottom-lighter IMF than the Milky Way, and this change in IMF also modifies inferred properties such as stellar mass and star formation rate. Several surprising new features appear, including significant constraints on the feedback mechanisms responsible for star formation and subsequent quenching. Additionally, the same techniques might indicate that most galaxies go through an earliest phase of star formation dominated by different feedback mechanisms and centered in galactic cores prior to the more typical star formation at later times.

2022-11-11
11:00
Is the Stellar Initial Mass Function Truly Universal?
Charles Steinhardt (DAWN)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Current techniques for analyzing large photometric catalogs are generally forced to assume a single, universal stellar initial mass function (IMF), although the IMF should be expected to vary depending upon conditions within a star-forming galaxy. The introduction of an additional parameter into photometric template fitting allows galaxies to be fit with a range of different IMFs. Most galaxies are best fit with a bottom-lighter IMF than the Milky Way, and this change in IMF also modifies inferred properties such as stellar mass and star formation rate. Several surprising new features appear, including significant constraints on the feedback mechanisms responsible for star formation and subsequent quenching. Additionally, the same techniques might indicate that most galaxies go through an earliest phase of star formation dominated by different feedback mechanisms and centered in galactic cores prior to the more typical star formation at later times.

2022-11-04
11:00
TBD
Mateusz Ruszkowski (University of Michigan)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-11-04
11:00
TBD
Mateusz Ruszkowski (University of Michigan)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-11-04
11:00
The role of cosmic rays, magnetic fields, and turbulence in AGN feedback
Mateusz Ruszkowski (University of Michigan)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
AGN play central role in shaping the properties of galaxies and solving the decades-old cooling flow problem. In this talk, I will discuss recent developments in the field of AGN jet feedback. I will focus on the role of cosmic rays, magnetic fields, and turbulence in shaping the observational properties of hot gaseous halos and on theoretical aspects of the energy transfer from the AGN jets to the ambient medium, i.e., the circumgalactic and intracluster medium (CGM and ICM, respectively). I will begin by discussing an example of supermassive black hole (SMBH) feedback in our own Galactic ''backyard'' — the Fermi Bubbles observed by Fermi in gamma-rays, Planck in microwaves, and, most recently, by eROSITA in X-rays. I will then discuss AGN jet feedback in elliptical galaxies and galaxy clusters. Specifically, I will discuss three new surprising findings: (i) that cosmic ray streaming heating is an important new channel for the AGN energy thermalization in the feedback process, (ii) that even extremely weak magnetic fields can dramatically alter the dynamics of the cold gas precipitation out of the CGM and ICM and feeding the SMBH, and (iii) that, contrary to textbook expectation, turbulence in the CGM/ICM may be non-Kolmogorov in nature. All of these findings have implications for the interpretation of observational results and for our understanding of AGN feedback in general.

2022-11-04
11:00
TBD
Mateusz Ruszkowski (University of Michigan)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-11-04
11:00
The role of cosmic rays, magnetic fields, and turbulence in AGN feedback
Mateusz Ruszkowski (University of Michigan)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
AGN play central role in shaping the properties of galaxies and solving the decades-old cooling flow problem. In this talk, I will discuss recent developments in the field of AGN jet feedback. I will focus on the role of cosmic rays, magnetic fields, and turbulence in shaping the observational properties of hot gaseous halos and on theoretical aspects of the energy transfer from the AGN jets to the ambient medium, i.e., the circumgalactic and intracluster medium (CGM and ICM, respectively). I will begin by discussing an example of supermassive black hole (SMBH) feedback in our own Galactic ''backyard'' — the Fermi Bubbles observed by Fermi in gamma-rays, Planck in microwaves, and, most recently, by eROSITA in X-rays. I will then discuss AGN jet feedback in elliptical galaxies and galaxy clusters. Specifically, I will discuss three new surprising findings: (i) that cosmic ray streaming heating is an important new channel for the AGN energy thermalization in the feedback process, (ii) that even extremely weak magnetic fields can dramatically alter the dynamics of the cold gas precipitation out of the CGM and ICM and feeding the SMBH, and (iii) that, contrary to textbook expectation, turbulence in the CGM/ICM may be non-Kolmogorov in nature. All of these findings have implications for the interpretation of observational results and for our understanding of AGN feedback in general.

2022-10-28
11:00
TBA
Niv Drory (U. of Texas/Austin)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-10-28
11:00
TBA
Niv Drory (U. of Texas/Austin)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-10-28
11:00
TBA
Niv Drory (U. of Texas/Austin)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-10-28
11:00
The Local Volume Mapper (LVM) Survey in SDSS-V: IFU spectroscopy of the Milky Way and Magellanic Clouds
Niv Drory (UT Austin)
Königstuhl Kolloquium
MPIA lecture hall,
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Abstract
The SDSS-V Local Volume Mapper (LVM) is an IFU survey covering 3500 sq degrees in the MW disk at 0.1-1 pc resolution and the Magellanic Clouds at 10 pc resolution, in total about 1 steradian of sky. It uses a full-moon sized fiber-fed IFU feeding spectrographs covering the full optical bandpass at R~4000 (4800 at Ha). LVM finely resolves star forming structures, GMCs, H II regions, diffuse gas and filaments, nebulae, and young stellar clusters across a wide range of physical parameters and environments. Ancillary data provide stellar spectroscopy from SDSS-III,IV and V, resolved (spectro-)photometry of individual stars and color-magnitude diagrams (CMDs), and X-Ray to radio data from a multitude of surveys. LVM probes the radiation field and wind momentum input of stars back into the ISM and together with the wide coverage addresses feedback from the single star scale up to kpc and galactic scales. It also addresses many open science questions regarding the composition, physical state and conditions in the ISM. Key science topics include the injection of feedback into the ISM, the star formation efficiency dependence on galactic environment, precision abundance diagnostics, the diffusion of heavy elements, the heating mechanisms of the diffuse ionized gas, the ionization structure of HII regions, the time evolution of star forming structures, and many other topics.

2022-10-21
11:00
TBC
Deanne Fisher (Swinburne U.)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-10-21
11:00
TBC
Deanne Fisher (Swinburne U.)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-10-21
11:00
TBC
Deanne Fisher (Swinburne U.)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-10-21
11:00
TBC
Deanne Fisher (Swinburne U.)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-10-21
11:00
Physical and chemical properties during high-mass star formation
Caroline Gieser (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
During high-mass star formation, fragmentation takes place on various spatial scales from giant molecular clouds down to disk scales. At the earliest evolutionary stages, high-mass protostars are still deeply embedded within their parental molecular cloud and can be studied best at high spatial resolution with interferometers at mm wavelengths.
The IRAM/NOEMA large program "CORE" allows us to analyze the physical and chemical properties of a sample of luminous high-mass star-forming regions. The 1 mm dust continuum of the sample shows a large diversity of fragmentation properties. Using the spectral line emission, we characterize the physical structure (temperature an density) and quantify the molecular content of individual fragmented cores. Even though all regions are classified to harbor high-mass protostellar objects, the molecular content shows a high degree of complexity. By combining the observed core properties, we are able to estimate chemical timescales with the physical-chemical model MUSCLE.
We find well-constrained density and temperature profiles in agreement with theoretical predictions. The molecular complexity in the core spectra can be explained by an age spread that is then confirmed by our physical-chemical modeling. The hot molecular cores show the greatest number of emission lines, but we also find evolved cores in which most molecules are destroyed and, thus, the spectra appear line-poor once again. We increased our sample with ALMA 3mm observations of 11 additional high-mass star-forming regions at different evolutionary stages - from infrared dark clouds to ultra-compact HII regions - in order to further investigate the evolution of the physical and chemical properties on core scales.

2022-10-14
11:00
TBA
Sabine Thater (University Vienna)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2022-10-14
11:00
TBA
Sabine Thater (University Vienna)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2022-10-14
11:00
TBA
Sabine Thater (University Vienna)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2022-10-14
11:00
Expanding the extreme ends of the massive black hole scaling relations with dynamical modelling
Sabine Thater (University Vienna)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
By now more than hundred massive black hole (MBH) mass measurements of local galaxies based on stellar or gaseous motion reveal strong correlations of the MBH mass with their bulge properties, such as bulge mass, stellar velocity dispersion (sigma) and light concentration. Determining MBH masses is a challenging procedure and it is not possible to use one single method across the full sample of galaxies. Problematically, measurements from different dynamical tracers often give discrepant results, rising the question whether the variety of methods forces an additional bias on the scaling relations. Therefore, connecting mass results from different methods is necessary to evaluate the robustness and universality of the measurement results and thus crucial for improving the understanding of the interplay between the central black holes and their host galaxies.

I will present two projects to address the following questions: Do high-mass and low-mass black holes follow the same scaling relations? Does the variety of mass measurement methods force an additional bias on the scaling relations? I will show two independent black hole determinations from the early-type galaxy NGC 6958 based on stellar kinematics (MUSE) and molecular gas kinematics (ALMA), taking special care in revisiting the associated measurement errors, specifically, the systematics associated with the dynamical methods, and the general accuracy of black hole mass measurements. NGC 6958 is part of the SMASHING sample of 20 early-type galaxies which expand the black hole scaling relations on both the high and low mass end. I will discuss the dynamically measured black hole masses in the SMASHING sample in context of the MBH mass-sigma relation. Finally, I will give an outlook to new features in the triaxial Schwarzschild chemo-dynamical modelling code that is developed in Vienna.

2022-10-07
11:00
TBD
Ralf Klessen (ITA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2022-10-07
11:00
TBD
Ralf Klessen (ITA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2022-10-07
11:00
TBD
Ralf Klessen (ITA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2022-10-07
11:00
TBD
Ralf Klessen (ITA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2022-09-30
11:00
A Tapestry of Starlight and Supermassive Black Holes
Alyssa Drake (Hertfordshire)
Königstuhl Kolloquium
MPIA lecture hall,
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Abstract
As new astronomical facilities come online, they offer the opportunity to transform our understanding of the Universe. One such facility is The International LOFAR Telescope, which is opening new parameter space in the low-frequency radio sky through its unprecedented combination of sensitivity, areal coverage and spatial resolution. In particular, the LOFAR Two Metre Sky Survey (LoTSS) is surveying the entire northern sky at 150MHz to a depth of ~100 micro Jy, already providing a sample of > 4 million extragalactic radio sources, and gathering statistical samples of both extreme quasars in the early Universe, and 'typical' star-forming galaxies across vast swathes of cosmic time. I will outline our current understanding of the build up of the first supermassive black holes, and the evolution of cosmic star formation, using state-of-the art facilities (e.g. MUSE and ALMA), before discussing how the advent of massively-multiplexed spectroscopic facilities such as WEAVE will unlock the immense potential of the LOFAR surveys. For instance, by providing > 1 million optical spectra of radio-selected sources, the WEAVE-LOFAR survey will be able to distinguish between star-formation and AGN, accretion modes in AGN, and ultimately enable us to understand the complex interplay between star formation and accretion from z~7 to the present day.

2022-09-23
11:00
TBD
Raphaël Errani (Obs. Strasbourg)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-09-23
11:00
TBD
Raphaël Errani (Obs. Strasbourg)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-09-23
11:00
TBD
Raphaël Errani (Obs. Strasbourg)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-09-23
11:00
Structure and kinematics of tidally limited satellite galaxies in LCDM
Raphaël Errani (Obs. Strasbourg)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract

Abstract: In the cold dark matter model, we think the Milky Way \;hosts many dark matter subhalos - some of them host luminous dwarf galaxies, others devoid of stars. \;In this talk, I'll discuss how cold dark matter substructures get trimmed down due to the Milky Way tidal field and how this affects embedded dwarf galaxies. \;In particular, I'll show that if dark matter subhalos have centrally-divergent density cusps, they are very resilient to tidal effects, and the sizes and velocity dispersions of heavily-stripped Milky Way satellite galaxies are set by the properties of their underlying dark matter subhalos. \;The results raise challenging questions about the nature of dark matter on galactic scales, as the existence of extended and dynamically cold Milky Way satellite galaxies, like the Crater 2 and Antlia 2 dwarfs, appears in conflict with simple predictions from cold dark matter models. \;


2022-09-16
11:00
TBA
Kathryn Kreckel (ZAH/ARI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2022-09-16
11:00
TBA
Kathryn Kreckel (ZAH/ARI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2022-09-16
11:00
TBA
Kathryn Kreckel (ZAH/ARI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2022-09-16
11:00
Resolving the Baryon Cycle within Nearby Galaxies

Kathryn Kreckel (ZAH/ARI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The buildup of stellar mass through star formation is driven on small (<100pc) scales by physical processes and local conditions, but regulated across larger (kpc) scales through the baryon cycle. This entails the transformation of gas into stars, and eventual ejection and recycling of material to form the next generation of stars. The ionized interstellar medium (ISM) provides crucial insights into these processes, particularly our understanding of radiative and mechanical feedback from young massive stars. The PHANGS (Physics at High Angular resolution in Nearby GalaxieS) collaboration is building a library of uniform, high-quality, high-resolution observations of nearby galaxies at the critical “cloud scale” across star-forming galaxy disks by using observations from Hubble, MUSE/VLT, JWST, and ALMA. This provides a characterization of the young star clusters, the ionized HII regions, the supernova remnants and the giant molecular clouds, with which we we can explore a comprehensive view of the star-formation process. I will present new results from my group, which has focused on quantifying the impact of these stellar feedback processes on the ISM. I will show how we are leveraging our large statistical samples to establish an evolutionary sequence for HII regions, linking ionized nebulae with their powering stellar sources. In charting the late-time and large-scale feedback, I will show how morphological identification of bubbles in molecular and ionized gas, and now with JWST in the dust, provides quantitative constraints on different feedback mechanisms.

2022-09-09
11:00
TBD
Camille Bergez (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2022-09-09
11:00
TBD
Camille Bergez (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2022-09-09
11:00
TBD
Camille Bergez (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2022-09-09
11:00
How the formation of multiple giant planets can impact their own growth and the structure of their protoplanetary disk
Camille Bergez (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Giant planets are partly formed by accretion of the gas present in the protoplanetary disk surrounding them. This process influences the shape of the protoplanetary disk as well as the growth of the giants themselves when considering more than one giant forming at the same time. I will present the results of my hydrodynamical simulations which investigate the evolution of the masses of the planets as a function of time as well as the evolution of the structures present in the protoplanetary disk. I will link these two quantities to observations of protoplanetary disks as well as the distributions of characteristics of the observed exoplanets.

2022-09-05
12:40
D
D (D)
Königstuhl Kolloquium
D, D
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Abstract
D

2022-09-02
11:00
Updates to the Maunakea Spectroscopic Explorer: Thousands of Fibers, Infinite Possibilities
: Andrew Sheinis (CFHT)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
MSE is a massively multiplexed spectroscopic survey facility that will replace the Canada-France-Hawaii-Telescope in the coming decade. This 11.25-m telescope, with its 1.5 square degree field-of-view, will observe 4,000 – 20,000 astronomical targets in every pointing by using fibers to pick up the light at the prime focus w and transmitting it to banks of low/moderate (R=3,000/6,000) and high (R=30,000) resolution spectrographs. Piezo actuators position individual fibers in the field of view to enable simultaneous full field coverage for both resolution modes. MSE will unveil the composition and dynamics of the faint Universe and impact nearly every ?eld of astrophysics across all spatial scales, from individual stars to the largest scale structures in the Universe, including (i) the ultimate Gaia follow-up facility for understanding the chemistry and dynamics of the distant Milky Way, including the outer disk and faint stellar halo at high spectral resolution (ii) galaxy formation and evolution at cosmic noon, (iii) derivation of the mass of the neutrino and insights into in?ationary physics through a cosmological redshift survey that probes a large volume of the Universe with a high galaxy density. The instrument suite, dedicated to large scale surveys, will enable MSE to collect a massive amount of data: equivalent to a full SDSS Legacy Survey every 7 weeks. We present an update to the major systems development for MSE along with the ongoing process of evaluating improvements to the baseline telescope design. In addition, we present the plan to develop a Pathfinder instrument at CFHT to fast-track development of the MSE technology as well as provide a the only wide-field spectroscopic capability in the visible and NIR in the Northern Hemisphere later in this decade.

2022-08-05
11:00
TBA
David Hogg (NYU, Flation Institute)
Königstuhl Kolloquium
MPIA lecture hall,
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Abstract
TBA

2022-08-05
11:00
TBA
David Hogg (NYU, Flation Institute)
Königstuhl Kolloquium
MPIA lecture hall,
Show/hide abstract

Abstract
TBA

2022-08-05
11:00
TBA
David Hogg (NYU, Flation Institute)
Königstuhl Kolloquium
MPIA lecture hall,
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Abstract
TBA

2022-08-05
11:00
Fitting very flexible models\n
David Hogg (NYU, Flation Institute)
Königstuhl Kolloquium
MPIA lecture hall,
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Abstract

Linear fitting is often used for interpolation of data, for example when you have calibration data and you want to fit a smooth, flexible function. Or you want to de-trend a time series or normalize a spectrum. I will discuss how this fitting is done, with ordinary least squares and extensions thereof. Extremely surprisingly, it is often valuable to choose far more parameters than data points, despite folk rules to the contrary\; over-fitting is not (mainly) a problem of having too many parameters. It is even possible to take the limit of infinite parameters, at which a regularized least-squares fit can become the mean of a Gaussian process, which is a very useful model. I recommend cross-validation as a practical method for model selection, and jackknife resampling as a practical method for estimating the uncertainties of the predictions made by the model. (work with Soledad Villar)




2022-07-29
11:00
Recent updates and highlights in high-contrast imaging of exoplanets
Matthias Samland (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The first generation of dedicated high-contrast imaging \;instrumentation has seen first light around 8 years ago (SPHERE, GPI), \;and a lot has changed in the intervening years. In this talk I provide \;an overview of recent development in instrumentation, data reduction, \;and atmospheric characterization (yes, also some JWST images).

2022-07-29
11:00
Recent updates and highlights in high-contrast imaging of exoplanets
Matthias Samland (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
The first generation of dedicated high-contrast imaging \;instrumentation has seen first light around 8 years ago (SPHERE, GPI), \;and a lot has changed in the intervening years. In this talk I provide \;an overview of recent development in instrumentation, data reduction, \;and atmospheric characterization (yes, also some JWST images).

2022-07-29
11:00
Recent updates and highlights in high-contrast imaging of exoplanets
Matthias Samland (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
The first generation of dedicated high-contrast imaging \;instrumentation has seen first light around 8 years ago (SPHERE, GPI), \;and a lot has changed in the intervening years. In this talk I provide \;an overview of recent development in instrumentation, data reduction, \;and atmospheric characterization (yes, also some JWST images).

2022-07-29
11:00
Recent updates and highlights in high-contrast imaging of exoplanets
Matthias Samland (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
The first generation of dedicated high-contrast imaging \;instrumentation has seen first light around 8 years ago (SPHERE, GPI), \;and a lot has changed in the intervening years. In this talk I provide \;an overview of recent development in instrumentation, data reduction, \;and atmospheric characterization (yes, also some JWST images).

2022-07-22
11:00
[Fe/H] and [a/Fe] from spectra of red giant stars across M31, M33, and beyond
Leigh Wojno (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
We present chemical abundances of red giant branch stars in the Andromeda (M31) system, including its dwarf satellites, as well as M33. We use spectral synthesis to obtain individual and coadded spectroscopic abundance measurements from R~6000 NIR spectra obtained as part of the Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo (SPLASH) survey. Spectra with insufficient S/N to determine individual abundance measurements are binned according to their photometric metallicity and coadded to obtain mean [Fe/H] and [a/Fe] for groups of similar stars. Using both individual and coadded abundance measurements, we measure a radial metallicity gradient in both [Fe/H] and [a/Fe] for stars associated with the “smooth” halo of M31, of -0.005±0.003 and 0.0034±0.0004 dex kpc-1, respectively. For stars more likely to be associated with substructure, we measure a similar gradient in [Fe/H], but do not find evidence for a radial gradient in [a/Fe]. Radial abundance gradients are associated with "inside out" galaxy formation, and we compare these gradients to those measured for the Milky Way. Finally, we explore the 2D [a/Fe]-[Fe/H] abundance space for M31, its satellite galaxies, and M33. By putting these abundance measurements into context with the local group, we aim to identify critical differences in the star formation and accretion history of M31 compared to that of our own Galaxy.

2022-07-22
11:00
[Fe/H] and [a/Fe] from spectra of red giant stars across M31, M33, and beyond
Leigh Wojno (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
We present chemical abundances of red giant branch stars in the Andromeda (M31) system, including its dwarf satellites, as well as M33. We use spectral synthesis to obtain individual and coadded spectroscopic abundance measurements from R~6000 NIR spectra obtained as part of the Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo (SPLASH) survey. Spectra with insufficient S/N to determine individual abundance measurements are binned according to their photometric metallicity and coadded to obtain mean [Fe/H] and [a/Fe] for groups of similar stars. Using both individual and coadded abundance measurements, we measure a radial metallicity gradient in both [Fe/H] and [a/Fe] for stars associated with the “smooth” halo of M31, of -0.005±0.003 and 0.0034±0.0004 dex kpc-1, respectively. For stars more likely to be associated with substructure, we measure a similar gradient in [Fe/H], but do not find evidence for a radial gradient in [a/Fe]. Radial abundance gradients are associated with "inside out" galaxy formation, and we compare these gradients to those measured for the Milky Way. Finally, we explore the 2D [a/Fe]-[Fe/H] abundance space for M31, its satellite galaxies, and M33. By putting these abundance measurements into context with the local group, we aim to identify critical differences in the star formation and accretion history of M31 compared to that of our own Galaxy.

2022-07-22
11:00
[Fe/H] and [a/Fe] from spectra of red giant stars across M31, M33, and beyond
Leigh Wojno (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
We present chemical abundances of red giant branch stars in the Andromeda (M31) system, including its dwarf satellites, as well as M33. We use spectral synthesis to obtain individual and coadded spectroscopic abundance measurements from R~6000 NIR spectra obtained as part of the Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo (SPLASH) survey. Spectra with insufficient S/N to determine individual abundance measurements are binned according to their photometric metallicity and coadded to obtain mean [Fe/H] and [a/Fe] for groups of similar stars. Using both individual and coadded abundance measurements, we measure a radial metallicity gradient in both [Fe/H] and [a/Fe] for stars associated with the “smooth” halo of M31, of -0.005±0.003 and 0.0034±0.0004 dex kpc-1, respectively. For stars more likely to be associated with substructure, we measure a similar gradient in [Fe/H], but do not find evidence for a radial gradient in [a/Fe]. Radial abundance gradients are associated with "inside out" galaxy formation, and we compare these gradients to those measured for the Milky Way. Finally, we explore the 2D [a/Fe]-[Fe/H] abundance space for M31, its satellite galaxies, and M33. By putting these abundance measurements into context with the local group, we aim to identify critical differences in the star formation and accretion history of M31 compared to that of our own Galaxy.

2022-07-22
11:00
[Fe/H] and [a/Fe] from spectra of red giant stars across M31, M33, and beyond
Leigh Wojno (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
We present chemical abundances of red giant branch stars in the Andromeda (M31) system, including its dwarf satellites, as well as M33. We use spectral synthesis to obtain individual and coadded spectroscopic abundance measurements from R~6000 NIR spectra obtained as part of the Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo (SPLASH) survey. Spectra with insufficient S/N to determine individual abundance measurements are binned according to their photometric metallicity and coadded to obtain mean [Fe/H] and [a/Fe] for groups of similar stars. Using both individual and coadded abundance measurements, we measure a radial metallicity gradient in both [Fe/H] and [a/Fe] for stars associated with the “smooth” halo of M31, of -0.005±0.003 and 0.0034±0.0004 dex kpc-1, respectively. For stars more likely to be associated with substructure, we measure a similar gradient in [Fe/H], but do not find evidence for a radial gradient in [a/Fe]. Radial abundance gradients are associated with "inside out" galaxy formation, and we compare these gradients to those measured for the Milky Way. Finally, we explore the 2D [a/Fe]-[Fe/H] abundance space for M31, its satellite galaxies, and M33. By putting these abundance measurements into context with the local group, we aim to identify critical differences in the star formation and accretion history of M31 compared to that of our own Galaxy.

2022-07-15
11:00
Large-Scale Structure Cosmology in the Systematics-Limited Regime
Elizabeth Krause (University of Arizona)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Over the next decade, large galaxy surveys will map billions of galaxies and probe cosmic structure formation with high statistical precision. This talk will outline opportunities and challenges of cosmological analyses in the presence of complex systematic effects using recent results from the Dark Energy Survey as pathfinder examples. In particular, I will describe different cosmological probes measured from photometric data and summarize the recent progress on combining galaxy clustering, weak lensing, cluster clustering and cluster abundances, as well as constraints on baryons and galaxy biasing from small scales. I will conclude with an outlook on cosmology analysis plans and challenges for future, much larger experiments such as Rubin Observatory's LSST, Roman Space Telescope and overlapping Cosmic Microwave Background surveys.

2022-07-15
11:00
Large-Scale Structure Cosmology in the Systematics-Limited Regime
Elizabeth Krause (University of Arizona)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Over the next decade, large galaxy surveys will map billions of galaxies and probe cosmic structure formation with high statistical precision. This talk will outline opportunities and challenges of cosmological analyses in the presence of complex systematic effects using recent results from the Dark Energy Survey as pathfinder examples. In particular, I will describe different cosmological probes measured from photometric data and summarize the recent progress on combining galaxy clustering, weak lensing, cluster clustering and cluster abundances, as well as constraints on baryons and galaxy biasing from small scales. I will conclude with an outlook on cosmology analysis plans and challenges for future, much larger experiments such as Rubin Observatory's LSST, Roman Space Telescope and overlapping Cosmic Microwave Background surveys.

2022-07-15
11:00
Large-Scale Structure Cosmology in the Systematics-Limited Regime
Elizabeth Krause (University of Arizona)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Over the next decade, large galaxy surveys will map billions of galaxies and probe cosmic structure formation with high statistical precision. This talk will outline opportunities and challenges of cosmological analyses in the presence of complex systematic effects using recent results from the Dark Energy Survey as pathfinder examples. In particular, I will describe different cosmological probes measured from photometric data and summarize the recent progress on combining galaxy clustering, weak lensing, cluster clustering and cluster abundances, as well as constraints on baryons and galaxy biasing from small scales. I will conclude with an outlook on cosmology analysis plans and challenges for future, much larger experiments such as Rubin Observatory's LSST, Roman Space Telescope and overlapping Cosmic Microwave Background surveys.

2022-07-15
11:00
Large-Scale Structure Cosmology in the Systematics-Limited Regime
Elizabeth Krause (University of Arizona)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Over the next decade, large galaxy surveys will map billions of galaxies and probe cosmic structure formation with high statistical precision. This talk will outline opportunities and challenges of cosmological analyses in the presence of complex systematic effects using recent results from the Dark Energy Survey as pathfinder examples. In particular, I will describe different cosmological probes measured from photometric data and summarize the recent progress on combining galaxy clustering, weak lensing, cluster clustering and cluster abundances, as well as constraints on baryons and galaxy biasing from small scales. I will conclude with an outlook on cosmology analysis plans and challenges for future, much larger experiments such as Rubin Observatory's LSST, Roman Space Telescope and overlapping Cosmic Microwave Background surveys.

2022-07-08
11:00
ANDES & The Promise of High Resolution Spectroscopy of Exoplanets
Wolfgang Gässler (MPIA) & Paul Mollière (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
High resolution spectroscopy is a powerful tool for many fields of astronomy, particularly exoplanet atmosphere characterization. In this talk we will introduce the ArmazoNes high Dispersion Echelle Spectrograph (ANDES), a planned ELT second-light instrument. ANDES will provide high resolution spectroscopy from optical wavelengths through the near-infrared (0.4-1.8 micron). We will give an overview of the instrument and discuss key exoplanet science cases, including measurements of the chemical composition, atmospheric dynamics, spin, and cloud properties. We will also discuss MPIA's planned contributions to the project, including a design study for expanding the instrument's wavelength coverage into the K band.

2022-07-08
11:00
ANDES & The Promise of High Resolution Spectroscopy of Exoplanets
Wolfgang Gässler (MPIA) & Paul Mollière (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
High resolution spectroscopy is a powerful tool for many fields of astronomy, particularly exoplanet atmosphere characterization. In this talk we will introduce the ArmazoNes high Dispersion Echelle Spectrograph (ANDES), a planned ELT second-light instrument. ANDES will provide high resolution spectroscopy from optical wavelengths through the near-infrared (0.4-1.8 micron). We will give an overview of the instrument and discuss key exoplanet science cases, including measurements of the chemical composition, atmospheric dynamics, spin, and cloud properties. We will also discuss MPIA's planned contributions to the project, including a design study for expanding the instrument's wavelength coverage into the K band.

2022-07-08
11:00
ANDES & The Promise of High Resolution Spectroscopy of Exoplanets
Wolfgang Gässler (MPIA) & Paul Mollière (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
High resolution spectroscopy is a powerful tool for many fields of astronomy, particularly exoplanet atmosphere characterization. In this talk we will introduce the ArmazoNes high Dispersion Echelle Spectrograph (ANDES), a planned ELT second-light instrument. ANDES will provide high resolution spectroscopy from optical wavelengths through the near-infrared (0.4-1.8 micron). We will give an overview of the instrument and discuss key exoplanet science cases, including measurements of the chemical composition, atmospheric dynamics, spin, and cloud properties. We will also discuss MPIA's planned contributions to the project, including a design study for expanding the instrument's wavelength coverage into the K band.

2022-07-08
11:00
ANDES & The Promise of High Resolution Spectroscopy of Exoplanets
Wolfgang Gässler (MPIA) & Paul Mollière (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
High resolution spectroscopy is a powerful tool for many fields of astronomy, particularly exoplanet atmosphere characterization. In this talk we will introduce the ArmazoNes high Dispersion Echelle Spectrograph (ANDES), a planned ELT second-light instrument. ANDES will provide high resolution spectroscopy from optical wavelengths through the near-infrared (0.4-1.8 micron). We will give an overview of the instrument and discuss key exoplanet science cases, including measurements of the chemical composition, atmospheric dynamics, spin, and cloud properties. We will also discuss MPIA's planned contributions to the project, including a design study for expanding the instrument's wavelength coverage into the K band.

2022-07-01
11:00
TBD
Giulia Perotti (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
TBD

2022-07-01
11:00
TBD
Matthias Samland (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2022-07-01
11:00
3D magneto-hydrodynamical model atmospheres: the influence of surface magnetism on the center-to-limb variation of solar-type stars
Hans-Günter Ludwig (LSW)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Observations indicate that magnetic activity has an influence on the center-to-limb variation (CLV) of solar-type stars. In my presentation, I review the magnetic activity of the Sun as template of activity of solar-type stars in general. I further review the observations conducted with the Kepler space observatory on transiting exo-planetary systems that motivated my project on the CLV. With the help of 3D magneto-hydrodynamical (MHD) model atmospheres a theoretical description of the observation is attempted. I describe the properties of the MHD models relevant for the project. MHD models are constructed which differ in the mean magnetic field strength. They are considered as elements suitable to build-up the stellar surface. Their radiative output for various stellar limb angles is calculated and compared to the measurements. A partial correspondence is achieved, however, discrepancies remain that may be of observational or theoretical origin. Not directly related to the project, and if time permits, I will finally comment on the impact of magnetic activity on Gaia photometry.

2022-07-01
11:00
3D magneto-hydrodynamical model atmospheres: the influence of surface magnetism on the center-to-limb variation of solar-type stars
Hans-Günter Ludwig (LSW)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Observations indicate that magnetic activity has an influence on the center-to-limb variation (CLV) of solar-type stars. In my presentation, I review the magnetic activity of the Sun as template of activity of solar-type stars in general. I further review the observations conducted with the Kepler space observatory on transiting exo-planetary systems that motivated my project on the CLV. With the help of 3D magneto-hydrodynamical (MHD) model atmospheres a theoretical description of the observation is attempted. I describe the properties of the MHD models relevant for the project. MHD models are constructed which differ in the mean magnetic field strength. They are considered as elements suitable to build-up the stellar surface. Their radiative output for various stellar limb angles is calculated and compared to the measurements. A partial correspondence is achieved, however, discrepancies remain that may be of observational or theoretical origin. Not directly related to the project, and if time permits, I will finally comment on the impact of magnetic activity on Gaia photometry.

2022-07-01
11:00
3D magneto-hydrodynamical model atmospheres: the influence of surface magnetism on the center-to-limb variation of solar-type stars
Hans-Günter Ludwig (LSW)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Observations indicate that magnetic activity has an influence on the center-to-limb variation (CLV) of solar-type stars. In my presentation, I review the magnetic activity of the Sun as template of activity of solar-type stars in general. I further review the observations conducted with the Kepler space observatory on transiting exo-planetary systems that motivated my project on the CLV. With the help of 3D magneto-hydrodynamical (MHD) model atmospheres a theoretical description of the observation is attempted. I describe the properties of the MHD models relevant for the project. MHD models are constructed which differ in the mean magnetic field strength. They are considered as elements suitable to build-up the stellar surface. Their radiative output for various stellar limb angles is calculated and compared to the measurements. A partial correspondence is achieved, however, discrepancies remain that may be of observational or theoretical origin. Not directly related to the project, and if time permits, I will finally comment on the impact of magnetic activity on Gaia photometry.

2022-07-01
11:00
3D magneto-hydrodynamical model atmospheres: the influence of surface magnetism on the center-to-limb variation of solar-type stars
Hans-Günter Ludwig (LSW)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Observations indicate that magnetic activity has an influence on the center-to-limb variation (CLV) of solar-type stars. In my presentation, I review the magnetic activity of the Sun as template of activity of solar-type stars in general. I further review the observations conducted with the Kepler space observatory on transiting exo-planetary systems that motivated my project on the CLV. With the help of 3D magneto-hydrodynamical (MHD) model atmospheres a theoretical description of the observation is attempted. I describe the properties of the MHD models relevant for the project. MHD models are constructed which differ in the mean magnetic field strength. They are considered as elements suitable to build-up the stellar surface. Their radiative output for various stellar limb angles is calculated and compared to the measurements. A partial correspondence is achieved, however, discrepancies remain that may be of observational or theoretical origin. Not directly related to the project, and if time permits, I will finally comment on the impact of magnetic activity on Gaia photometry.

2022-06-24
11:00
New insights on the formation of the terrestrial planets
Jingyi Mah (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
High-precision cosmochemistry data from meteorites suggest that the Earth, Mars and asteroid Vesta are compositionally distinct and that the compositions of these three objects appear to correlate with their distance from the Sun. These cosmochemistry observations can be used to constrain plausible formation pathways of the terrestrial planets in the inner Solar System. In particular, recent work has shown that aside from the classical view of collisions by increasingly massive planetesimals, the accretion of mm to m-sized pebbles can also reproduce the mass-orbit distribution of the terrestrial planets, igniting new debates in the community. In this talk I will discuss my work aiming to determine the more plausible formation pathway of the terrestrial planets by combining N-body simulations with constraints from cosmochemistry data.

2022-06-24
11:00
New insights on the formation of the terrestrial planets
Jingyi Mah (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
High-precision cosmochemistry data from meteorites suggest that the Earth, Mars and asteroid Vesta are compositionally distinct and that the compositions of these three objects appear to correlate with their distance from the Sun. These cosmochemistry observations can be used to constrain plausible formation pathways of the terrestrial planets in the inner Solar System. In particular, recent work has shown that aside from the classical view of collisions by increasingly massive planetesimals, the accretion of mm to m-sized pebbles can also reproduce the mass-orbit distribution of the terrestrial planets, igniting new debates in the community. In this talk I will discuss my work aiming to determine the more plausible formation pathway of the terrestrial planets by combining N-body simulations with constraints from cosmochemistry data.

2022-06-24
11:00
New insights on the formation of the terrestrial planets
Jingyi Mah (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
High-precision cosmochemistry data from meteorites suggest that the Earth, Mars and asteroid Vesta are compositionally distinct and that the compositions of these three objects appear to correlate with their distance from the Sun. These cosmochemistry observations can be used to constrain plausible formation pathways of the terrestrial planets in the inner Solar System. In particular, recent work has shown that aside from the classical view of collisions by increasingly massive planetesimals, the accretion of mm to m-sized pebbles can also reproduce the mass-orbit distribution of the terrestrial planets, igniting new debates in the community. In this talk I will discuss my work aiming to determine the more plausible formation pathway of the terrestrial planets by combining N-body simulations with constraints from cosmochemistry data.

2022-06-24
11:00
New insights on the formation of the terrestrial planets
Jingyi Mah (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
High-precision cosmochemistry data from meteorites suggest that the Earth, Mars and asteroid Vesta are compositionally distinct and that the compositions of these three objects appear to correlate with their distance from the Sun. These cosmochemistry observations can be used to constrain plausible formation pathways of the terrestrial planets in the inner Solar System. In particular, recent work has shown that aside from the classical view of collisions by increasingly massive planetesimals, the accretion of mm to m-sized pebbles can also reproduce the mass-orbit distribution of the terrestrial planets, igniting new debates in the community. In this talk I will discuss my work aiming to determine the more plausible formation pathway of the terrestrial planets by combining N-body simulations with constraints from cosmochemistry data.

2022-06-17
11:00
TBA
Anders Johansen (The Globe Institute, Copenhagen)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2022-06-17
11:00
3D magneto-hydrodynamical model atmospheres: the influence of surface magnetism on the center-to-limb variation of solar-type stars
Hans-Günter Ludwig (LSW)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-06-17
11:00
Quasars and the intergalactic medium at cosmic dawn
Xiaohui Fan (University of Arizona)
Königstuhl Kolloquium
MPIA lecture hall,
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Abstract
High-redshift quasars provide direct probes to the formation of the earliest supermassive black holes, their connections to early galaxy formation, and the history of cosmic reionization. More than 200 quasars have now been discovered in the first billion years of the cosmic history, with the highest redshift currently at z=7.6, indicating that billion solar mass black holes have already fully formed merely half billion years after the first star formation in the universe. I will (1) review the current state of high-redshift quasar surveys and discoveries, as a result of the new generations of wide-field sky surveys and developments in data mining and machine learning\; (2) discuss using high-redshift quasars as probes to the history of supermassive black hole growth in the early universe, using measurements of quasar luminosity function and black hole masses\; (3) present the latest observations of the the co-evolution of early SMBH growth and galaxy formation, and the roles quasar played in early galaxy formation and structure formation\; and (4) review the progress of using IGM absorption in quasar sightlines and properties of quasar proximity zones, which is unveiling a rapid and highly inhomogeneous reionization process at z~5.5 - 7.5. I will close with a discussion about the future of high-redshift quasar research, in the context of facilities such as JWST, LSST and Roman Space Telescope.

2022-06-17
11:00
Quasars and the intergalactic medium at cosmic dawn
Xiaohui Fan (University of Arizona)
Königstuhl Kolloquium
MPIA lecture hall,
Show/hide abstract

Abstract
High-redshift quasars provide direct probes to the formation of the earliest supermassive black holes, their connections to early galaxy formation, and the history of cosmic reionization. More than 200 quasars have now been discovered in the first billion years of the cosmic history, with the highest redshift currently at z=7.6, indicating that billion solar mass black holes have already fully formed merely half billion years after the first star formation in the universe. I will (1) review the current state of high-redshift quasar surveys and discoveries, as a result of the new generations of wide-field sky surveys and developments in data mining and machine learning\; (2) discuss using high-redshift quasars as probes to the history of supermassive black hole growth in the early universe, using measurements of quasar luminosity function and black hole masses\; (3) present the latest observations of the the co-evolution of early SMBH growth and galaxy formation, and the roles quasar played in early galaxy formation and structure formation\; and (4) review the progress of using IGM absorption in quasar sightlines and properties of quasar proximity zones, which is unveiling a rapid and highly inhomogeneous reionization process at z~5.5 - 7.5. I will close with a discussion about the future of high-redshift quasar research, in the context of facilities such as JWST, LSST and Roman Space Telescope.

2022-06-17
11:00
Quasars and the intergalactic medium at cosmic dawn
Xiaohui Fan (University of Arizona)
Königstuhl Kolloquium
MPIA lecture hall,
Show/hide abstract

Abstract
High-redshift quasars provide direct probes to the formation of the earliest supermassive black holes, their connections to early galaxy formation, and the history of cosmic reionization. More than 200 quasars have now been discovered in the first billion years of the cosmic history, with the highest redshift currently at z=7.6, indicating that billion solar mass black holes have already fully formed merely half billion years after the first star formation in the universe. I will (1) review the current state of high-redshift quasar surveys and discoveries, as a result of the new generations of wide-field sky surveys and developments in data mining and machine learning\; (2) discuss using high-redshift quasars as probes to the history of supermassive black hole growth in the early universe, using measurements of quasar luminosity function and black hole masses\; (3) present the latest observations of the the co-evolution of early SMBH growth and galaxy formation, and the roles quasar played in early galaxy formation and structure formation\; and (4) review the progress of using IGM absorption in quasar sightlines and properties of quasar proximity zones, which is unveiling a rapid and highly inhomogeneous reionization process at z~5.5 - 7.5. I will close with a discussion about the future of high-redshift quasar research, in the context of facilities such as JWST, LSST and Roman Space Telescope.

2022-06-17
11:00
Quasars and the intergalactic medium at cosmic dawn
Xiaohui Fan (University of Arizona)
Königstuhl Kolloquium
MPIA lecture hall,
Show/hide abstract

Abstract
High-redshift quasars provide direct probes to the formation of the earliest supermassive black holes, their connections to early galaxy formation, and the history of cosmic reionization. More than 200 quasars have now been discovered in the first billion years of the cosmic history, with the highest redshift currently at z=7.6, indicating that billion solar mass black holes have already fully formed merely half billion years after the first star formation in the universe. I will (1) review the current state of high-redshift quasar surveys and discoveries, as a result of the new generations of wide-field sky surveys and developments in data mining and machine learning\; (2) discuss using high-redshift quasars as probes to the history of supermassive black hole growth in the early universe, using measurements of quasar luminosity function and black hole masses\; (3) present the latest observations of the the co-evolution of early SMBH growth and galaxy formation, and the roles quasar played in early galaxy formation and structure formation\; and (4) review the progress of using IGM absorption in quasar sightlines and properties of quasar proximity zones, which is unveiling a rapid and highly inhomogeneous reionization process at z~5.5 - 7.5. I will close with a discussion about the future of high-redshift quasar research, in the context of facilities such as JWST, LSST and Roman Space Telescope.

2022-06-10
11:00
Gaia Data Release 3
Coryn Bailer-Jones (MPIA)
Königstuhl Kolloquium
MPIA lecture hall,
Show/hide abstract

Abstract
Gaia Data Release 3 will take place on Monday 13 June. This is the second part of the third release, following on from the release of the main astrometry and photometry in December 2020. I will give an overview of what is new in this release and what to expect. All of the MPIA-Gaia team will be on hand to answer your questions, although answers to some will no doubt have to wait until Monday.

2022-06-10
11:00
Gaia Data Release 3
Coryn Bailer-Jones (MPIA)
Königstuhl Kolloquium
MPIA lecture hall,
Show/hide abstract

Abstract
Gaia Data Release 3 will take place on Monday 13 June. This is the second part of the third release, following on from the release of the main astrometry and photometry in December 2020. I will give an overview of what is new in this release and what to expect. All of the MPIA-Gaia team will be on hand to answer your questions, although answers to some will no doubt have to wait until Monday.

2022-06-10
11:00
Gaia Data Release 3
Coryn Bailer-Jones (MPIA)
Königstuhl Kolloquium
MPIA lecture hall,
Show/hide abstract

Abstract
Gaia Data Release 3 will take place on Monday 13 June. This is the second part of the third release, following on from the release of the main astrometry and photometry in December 2020. I will give an overview of what is new in this release and what to expect. All of the MPIA-Gaia team will be on hand to answer your questions, although answers to some will no doubt have to wait until Monday.

2022-06-10
11:00
Gaia Data Release 3
Coryn Bailer-Jones (MPIA)
Königstuhl Kolloquium
MPIA lecture hall,
Show/hide abstract

Abstract
Gaia Data Release 3 will take place on Monday 13 June. This is the second part of the third release, following on from the release of the main astrometry and photometry in December 2020. I will give an overview of what is new in this release and what to expect. All of the MPIA-Gaia team will be on hand to answer your questions, although answers to some will no doubt have to wait until Monday.

2022-06-03
11:00
From Planet-forming Disks to
Ilaria Pascucci (LPL, Tuscon)
Königstuhl Kolloquium
MPIA lecture hall,
Show/hide abstract

Abstract
How did our Solar System and other planet systems form? Which systems are most likely to host habitable worlds? These are critical questions as we plan for missions capable of detecting Earth analogues and search for atmospheric signatures of life. I will discuss how linking multi-wavelength observations of disks around young stars and exoplanet demographics sheds light on these questions. First, I will present evidence for a dominant mechanism to form giant planets. Then, I will discuss an ongoing effort to constrain how the most common planets, sub-Neptunes and super-Earths, form. I will conclude by discussing how upcoming facilities will further these studies and their role in reconstructing the paths to habitable worlds.

2022-06-03
11:00
From Planet-forming Disks to
Ilaria Pascucci (LPL, Tuscon)
Königstuhl Kolloquium
MPIA lecture hall,
Show/hide abstract

Abstract
How did our Solar System and other planet systems form? Which systems are most likely to host habitable worlds? These are critical questions as we plan for missions capable of detecting Earth analogues and search for atmospheric signatures of life. I will discuss how linking multi-wavelength observations of disks around young stars and exoplanet demographics sheds light on these questions. First, I will present evidence for a dominant mechanism to form giant planets. Then, I will discuss an ongoing effort to constrain how the most common planets, sub-Neptunes and super-Earths, form. I will conclude by discussing how upcoming facilities will further these studies and their role in reconstructing the paths to habitable worlds.

2022-06-03
11:00
From Planet-forming Disks to
Ilaria Pascucci (LPL, Tuscon)
Königstuhl Kolloquium
MPIA lecture hall,
Show/hide abstract

Abstract
How did our Solar System and other planet systems form? Which systems are most likely to host habitable worlds? These are critical questions as we plan for missions capable of detecting Earth analogues and search for atmospheric signatures of life. I will discuss how linking multi-wavelength observations of disks around young stars and exoplanet demographics sheds light on these questions. First, I will present evidence for a dominant mechanism to form giant planets. Then, I will discuss an ongoing effort to constrain how the most common planets, sub-Neptunes and super-Earths, form. I will conclude by discussing how upcoming facilities will further these studies and their role in reconstructing the paths to habitable worlds.

2022-06-03
11:00
TBD
Ilaria Pascucci (LPL, Tuscon)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
TBD

2022-06-03
11:00
From Planet-forming Disks to
Ilaria Pascucci (LPL, Tuscon)
Königstuhl Kolloquium
MPIA lecture hall,
Show/hide abstract

Abstract
How did our Solar System and other planet systems form? Which systems are most likely to host habitable worlds? These are critical questions as we plan for missions capable of detecting Earth analogues and search for atmospheric signatures of life. I will discuss how linking multi-wavelength observations of disks around young stars and exoplanet demographics sheds light on these questions. First, I will present evidence for a dominant mechanism to form giant planets. Then, I will discuss an ongoing effort to constrain how the most common planets, sub-Neptunes and super-Earths, form. I will conclude by discussing how upcoming facilities will further these studies and their role in reconstructing the paths to habitable worlds.

2022-05-27
11:00
TBA
Jennifer (Leigh) Wojno (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2022-05-27
11:00
On Modelling Complex Systems in Astronomy
Yuan-Sen Ting (ANU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Astronomy today is fundamentally different than it was even just a decade ago. Our increasing ability to collect a large amount of data from ever more powerful instrumental has enabled many new opportunities. However, such opportunity also comes with new challenges. The bottleneck stems from the fact that most astronomical observations are inherently high dimension — from “imaging” the Universe at the finest details to fully characterising tens of millions of spectra consisting of tens of thousands of wavelength pixels. In this regime, classical astrostatistics approaches struggle.

I will present two different machine learning approaches to quantify complex systems in astronomy. (1) Reductionist approach: I will discuss how machine learning can optimally compress information and extract higher-order moment information in stochastic processes. (2) A generative approach: I will discuss how generative models, such as normalising flow, allow us to properly model the vast astronomy data set, enabling the study of complex astronomy systems directly in their raw dimensional space.

2022-05-27
11:00
On Modelling Complex Systems in Astronomy
Yuan-Sen Ting (ANU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Astronomy today is fundamentally different than it was even just a decade ago. Our increasing ability to collect a large amount of data from ever more powerful instrumental has enabled many new opportunities. However, such opportunity also comes with new challenges. The bottleneck stems from the fact that most astronomical observations are inherently high dimension — from “imaging” the Universe at the finest details to fully characterising tens of millions of spectra consisting of tens of thousands of wavelength pixels. In this regime, classical astrostatistics approaches struggle.

I will present two different machine learning approaches to quantify complex systems in astronomy. (1) Reductionist approach: I will discuss how machine learning can optimally compress information and extract higher-order moment information in stochastic processes. (2) A generative approach: I will discuss how generative models, such as normalising flow, allow us to properly model the vast astronomy data set, enabling the study of complex astronomy systems directly in their raw dimensional space.

2022-05-27
11:00
On Modelling Complex Systems in Astronomy
Yuan-Sen Ting (ANU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Astronomy today is fundamentally different than it was even just a decade ago. Our increasing ability to collect a large amount of data from ever more powerful instrumental has enabled many new opportunities. However, such opportunity also comes with new challenges. The bottleneck stems from the fact that most astronomical observations are inherently high dimension — from “imaging” the Universe at the finest details to fully characterising tens of millions of spectra consisting of tens of thousands of wavelength pixels. In this regime, classical astrostatistics approaches struggle.

I will present two different machine learning approaches to quantify complex systems in astronomy. (1) Reductionist approach: I will discuss how machine learning can optimally compress information and extract higher-order moment information in stochastic processes. (2) A generative approach: I will discuss how generative models, such as normalising flow, allow us to properly model the vast astronomy data set, enabling the study of complex astronomy systems directly in their raw dimensional space.

2022-05-27
11:00
On Modelling Complex Systems in Astronomy
Yuan-Sen Ting (ANU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Astronomy today is fundamentally different than it was even just a decade ago. Our increasing ability to collect a large amount of data from ever more powerful instrumental has enabled many new opportunities. However, such opportunity also comes with new challenges. The bottleneck stems from the fact that most astronomical observations are inherently high dimension — from “imaging” the Universe at the finest details to fully characterising tens of millions of spectra consisting of tens of thousands of wavelength pixels. In this regime, classical astrostatistics approaches struggle.

I will present two different machine learning approaches to quantify complex systems in astronomy. (1) Reductionist approach: I will discuss how machine learning can optimally compress information and extract higher-order moment information in stochastic processes. (2) A generative approach: I will discuss how generative models, such as normalising flow, allow us to properly model the vast astronomy data set, enabling the study of complex astronomy systems directly in their raw dimensional space.

2022-05-20
11:00
High contrast detection and characterization of exoplanets using high resolution spectroscopy
Dimitri Mawet (Caltech)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Twenty-seven years after the discovery of the first planet orbiting a star other than the Sun, it is now clear that extrasolar planets are ubiquitous in the galaxy. Though our understanding of exoplanet demographics has dramatically expanded in recent years, many fundamental questions about their origin and composition remain. High-precision high-resolution spectroscopy (HRS) at the diffraction limit of large telescopes enables the most detailed measurements of exoplanet properties, including their atmospheric composition and dynamics, orbits, and masses. I will present recent results obtained with the Keck Planet Imager and Characterizer (KPIC) at W.M. Keck Observatory as well as prospects for revolutionary advances in exoplanet detection and characterization with future ground- and space-based facilities.

2022-05-20
11:00
High contrast detection and characterization of exoplanets using high resolution spectroscopy
Dimitri Mawet (Caltech)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Twenty-seven years after the discovery of the first planet orbiting a star other than the Sun, it is now clear that extrasolar planets are ubiquitous in the galaxy. Though our understanding of exoplanet demographics has dramatically expanded in recent years, many fundamental questions about their origin and composition remain. High-precision high-resolution spectroscopy (HRS) at the diffraction limit of large telescopes enables the most detailed measurements of exoplanet properties, including their atmospheric composition and dynamics, orbits, and masses. I will present recent results obtained with the Keck Planet Imager and Characterizer (KPIC) at W.M. Keck Observatory as well as prospects for revolutionary advances in exoplanet detection and characterization with future ground- and space-based facilities.

2022-05-20
11:00
High contrast detection and characterization of exoplanets using high resolution spectroscopy
Dimitri Mawet (Caltech)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Twenty-seven years after the discovery of the first planet orbiting a star other than the Sun, it is now clear that extrasolar planets are ubiquitous in the galaxy. Though our understanding of exoplanet demographics has dramatically expanded in recent years, many fundamental questions about their origin and composition remain. High-precision high-resolution spectroscopy (HRS) at the diffraction limit of large telescopes enables the most detailed measurements of exoplanet properties, including their atmospheric composition and dynamics, orbits, and masses. I will present recent results obtained with the Keck Planet Imager and Characterizer (KPIC) at W.M. Keck Observatory as well as prospects for revolutionary advances in exoplanet detection and characterization with future ground- and space-based facilities.

2022-05-20
11:00
High contrast detection and characterization of exoplanets using high resolution spectroscopy
Dimitri Mawet (Caltech)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Twenty-seven years after the discovery of the first planet orbiting a star other than the Sun, it is now clear that extrasolar planets are ubiquitous in the galaxy. Though our understanding of exoplanet demographics has dramatically expanded in recent years, many fundamental questions about their origin and composition remain. High-precision high-resolution spectroscopy (HRS) at the diffraction limit of large telescopes enables the most detailed measurements of exoplanet properties, including their atmospheric composition and dynamics, orbits, and masses. I will present recent results obtained with the Keck Planet Imager and Characterizer (KPIC) at W.M. Keck Observatory as well as prospects for revolutionary advances in exoplanet detection and characterization with future ground- and space-based facilities.

2022-05-13
11:00
Three Years of Research of the Planet Genesis Group at MPIA
Paola Pinilla (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Since the first high angular resolution observation of a protoplanetary disk using ALMA eight years ago, our understanding of the structure and evolution of protoplanetary disks has been revolutionized. Ever since then, hundreds of disks have been observed with ALMA and SPHERE/VLT at high angular resolution, and they have been found in disks with different properties (for example: age, stellar mass). Disk substructures are key for planet formation: as dust traps, they are the regions where pebbles and planetesimals form. Although disk substructures have been detected is several protoplanetary disks, their origin, evolution, and properties remain unknown. The “Genesis of Planets” group at MPIA have been investigated the potential origin of these substructures, how can we observationally distinguish different origins, the effect of the stellar properties and disk environment, among others. In this colloquium, I will summarize the main results of the last three years of my group research and I will give a short overview of the near future in this field.

2022-05-13
11:00
Three Years of Research of the Planet Genesis Group at MPIA
Paola Pinilla (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Since the first high angular resolution observation of a protoplanetary disk using ALMA eight years ago, our understanding of the structure and evolution of protoplanetary disks has been revolutionized. Ever since then, hundreds of disks have been observed with ALMA and SPHERE/VLT at high angular resolution, and they have been found in disks with different properties (for example: age, stellar mass). Disk substructures are key for planet formation: as dust traps, they are the regions where pebbles and planetesimals form. Although disk substructures have been detected is several protoplanetary disks, their origin, evolution, and properties remain unknown. The “Genesis of Planets” group at MPIA have been investigated the potential origin of these substructures, how can we observationally distinguish different origins, the effect of the stellar properties and disk environment, among others. In this colloquium, I will summarize the main results of the last three years of my group research and I will give a short overview of the near future in this field.

2022-05-13
11:00
Three Years of Research of the Planet Genesis Group at MPIA
Paola Pinilla (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Since the first high angular resolution observation of a protoplanetary disk using ALMA eight years ago, our understanding of the structure and evolution of protoplanetary disks has been revolutionized. Ever since then, hundreds of disks have been observed with ALMA and SPHERE/VLT at high angular resolution, and they have been found in disks with different properties (for example: age, stellar mass). Disk substructures are key for planet formation: as dust traps, they are the regions where pebbles and planetesimals form. Although disk substructures have been detected is several protoplanetary disks, their origin, evolution, and properties remain unknown. The “Genesis of Planets” group at MPIA have been investigated the potential origin of these substructures, how can we observationally distinguish different origins, the effect of the stellar properties and disk environment, among others. In this colloquium, I will summarize the main results of the last three years of my group research and I will give a short overview of the near future in this field.

2022-05-13
11:00
Three Years of Research of the Planet Genesis Group at MPIA
Paola Pinilla (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Since the first high angular resolution observation of a protoplanetary disk using ALMA eight years ago, our understanding of the structure and evolution of protoplanetary disks has been revolutionized. Ever since then, hundreds of disks have been observed with ALMA and SPHERE/VLT at high angular resolution, and they have been found in disks with different properties (for example: age, stellar mass). Disk substructures are key for planet formation: as dust traps, they are the regions where pebbles and planetesimals form. Although disk substructures have been detected is several protoplanetary disks, their origin, evolution, and properties remain unknown. The “Genesis of Planets” group at MPIA have been investigated the potential origin of these substructures, how can we observationally distinguish different origins, the effect of the stellar properties and disk environment, among others. In this colloquium, I will summarize the main results of the last three years of my group research and I will give a short overview of the near future in this field.

2022-05-06
11:00
TBA
Michael Küffmeier (University of Virginia/MPE)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2022-05-06
11:00
The Pristine survey: Galactic Archaeology with the very metal-poor (and very old) Milky Way
Nicolas Martin (Obs. Strasbourg)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
I will present the latest results from the Pristine collaboration that builds on a large photometric survey of the Northern sky with a narrow-band filter that focuses on the metallicity-sensitive Ca H&K lines and that yields accurate metallicities for tens of millions of stars. I will show that Pristine is very efficient at finding extremely metal-poor stars ([Fe/H]<-3.0 dex), whose chemistry holds information about the very first stars\; that we are starting to lift the veil on the distribution and, when combined with the exquisite Gaia astrometric information, the orbits of these oldest stars in the Milky Way and in dwarf galaxies\; and that, with the advent of near-future, large spectroscopic surveys like WEAVE, we shall soon have an unprecedented view of the assembly of the Milky Way at the earliest times.

2022-05-06
11:00
The Pristine survey: Galactic Archaeology with the very metal-poor (and very old) Milky Way
Nicolas Martin (Obs. Strasbourg)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
I will present the latest results from the Pristine collaboration that builds on a large photometric survey of the Northern sky with a narrow-band filter that focuses on the metallicity-sensitive Ca H&K lines and that yields accurate metallicities for tens of millions of stars. I will show that Pristine is very efficient at finding extremely metal-poor stars ([Fe/H]<-3.0 dex), whose chemistry holds information about the very first stars\; that we are starting to lift the veil on the distribution and, when combined with the exquisite Gaia astrometric information, the orbits of these oldest stars in the Milky Way and in dwarf galaxies\; and that, with the advent of near-future, large spectroscopic surveys like WEAVE, we shall soon have an unprecedented view of the assembly of the Milky Way at the earliest times.

2022-05-06
11:00
The Pristine survey: Galactic Archaeology with the very metal-poor (and very old) Milky Way
Nicolas Martin (Obs. Strasbourg)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
I will present the latest results from the Pristine collaboration that builds on a large photometric survey of the Northern sky with a narrow-band filter that focuses on the metallicity-sensitive Ca H&K lines and that yields accurate metallicities for tens of millions of stars. I will show that Pristine is very efficient at finding extremely metal-poor stars ([Fe/H]<-3.0 dex), whose chemistry holds information about the very first stars\; that we are starting to lift the veil on the distribution and, when combined with the exquisite Gaia astrometric information, the orbits of these oldest stars in the Milky Way and in dwarf galaxies\; and that, with the advent of near-future, large spectroscopic surveys like WEAVE, we shall soon have an unprecedented view of the assembly of the Milky Way at the earliest times.

2022-05-06
11:00
The Pristine survey: Galactic Archaeology with the very metal-poor (and very old) Milky Way
Nicolas Martin (Obs. Strasbourg)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
I will present the latest results from the Pristine collaboration that builds on a large photometric survey of the Northern sky with a narrow-band filter that focuses on the metallicity-sensitive Ca H&K lines and that yields accurate metallicities for tens of millions of stars. I will show that Pristine is very efficient at finding extremely metal-poor stars ([Fe/H]<-3.0 dex), whose chemistry holds information about the very first stars\; that we are starting to lift the veil on the distribution and, when combined with the exquisite Gaia astrometric information, the orbits of these oldest stars in the Milky Way and in dwarf galaxies\; and that, with the advent of near-future, large spectroscopic surveys like WEAVE, we shall soon have an unprecedented view of the assembly of the Milky Way at the earliest times.

2022-04-29
11:00
Active Galactic Nuclei on the Smallest Scales: Imaging the Circumnuclear Dust with MATISSE
Jacob Isbell (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Active galactic nuclei (AGN) play a key role in galaxy formation and evolution, but they remain shrouded in dust and in mystery. The dust surrounding the AGN on parsec scales traces the molecular gas responsible for AGN feeding, causes the diversity of AGN types, and may be an important channel for interaction with the host galaxy. The small physical scales of the dust structures means that the so-called "torus" remains unresolved with 10m-class telescopes, and instead we use the mid-infrared interferometer, VLTI MATISSE, to study a small number of nearby Seyfert AGN. The Circinus Galaxy is the nearest Seyfert 2, and using MATISSE we have imaged its circumnuclear dust for the first time. It is clear that a smooth torus is no longer a sufficient description of the dust. Instead we find a 1.9 pc diameter thin disk and patchy emission perpendicular to it. We find strong evidence of dust clumpiness and ~3pc scale warm dust emission consistent with radiation-driven outflow models. We also showed in imaging of NGC 1068 that the SMBH was obscured by a warm, nearly edge-on disk. We identified emission from polar flows and absorbing dust that is mineralogically distinct from standard ISM dust, indicating possible dust recycling. These results place new constraints on hydrodynamical and radiation transfer modeling, and have implications for the Unified Model of AGN.

2022-04-29
11:00
Active Galactic Nuclei on the Smallest Scales: Imaging the Circumnuclear Dust with MATISSE
Jacob Isbell (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Active galactic nuclei (AGN) play a key role in galaxy formation and evolution, but they remain shrouded in dust and in mystery. The dust surrounding the AGN on parsec scales traces the molecular gas responsible for AGN feeding, causes the diversity of AGN types, and may be an important channel for interaction with the host galaxy. The small physical scales of the dust structures means that the so-called "torus" remains unresolved with 10m-class telescopes, and instead we use the mid-infrared interferometer, VLTI MATISSE, to study a small number of nearby Seyfert AGN. The Circinus Galaxy is the nearest Seyfert 2, and using MATISSE we have imaged its circumnuclear dust for the first time. It is clear that a smooth torus is no longer a sufficient description of the dust. Instead we find a 1.9 pc diameter thin disk and patchy emission perpendicular to it. We find strong evidence of dust clumpiness and ~3pc scale warm dust emission consistent with radiation-driven outflow models. We also showed in imaging of NGC 1068 that the SMBH was obscured by a warm, nearly edge-on disk. We identified emission from polar flows and absorbing dust that is mineralogically distinct from standard ISM dust, indicating possible dust recycling. These results place new constraints on hydrodynamical and radiation transfer modeling, and have implications for the Unified Model of AGN.

2022-04-29
11:00
Active Galactic Nuclei on the Smallest Scales: Imaging the Circumnuclear Dust with MATISSE
Jacob Isbell (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Active galactic nuclei (AGN) play a key role in galaxy formation and evolution, but they remain shrouded in dust and in mystery. The dust surrounding the AGN on parsec scales traces the molecular gas responsible for AGN feeding, causes the diversity of AGN types, and may be an important channel for interaction with the host galaxy. The small physical scales of the dust structures means that the so-called "torus" remains unresolved with 10m-class telescopes, and instead we use the mid-infrared interferometer, VLTI MATISSE, to study a small number of nearby Seyfert AGN. The Circinus Galaxy is the nearest Seyfert 2, and using MATISSE we have imaged its circumnuclear dust for the first time. It is clear that a smooth torus is no longer a sufficient description of the dust. Instead we find a 1.9 pc diameter thin disk and patchy emission perpendicular to it. We find strong evidence of dust clumpiness and ~3pc scale warm dust emission consistent with radiation-driven outflow models. We also showed in imaging of NGC 1068 that the SMBH was obscured by a warm, nearly edge-on disk. We identified emission from polar flows and absorbing dust that is mineralogically distinct from standard ISM dust, indicating possible dust recycling. These results place new constraints on hydrodynamical and radiation transfer modeling, and have implications for the Unified Model of AGN.

2022-04-29
11:00
Active Galactic Nuclei on the Smallest Scales: Imaging the Circumnuclear Dust with MATISSE
Jacob Isbell (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Active galactic nuclei (AGN) play a key role in galaxy formation and evolution, but they remain shrouded in dust and in mystery. The dust surrounding the AGN on parsec scales traces the molecular gas responsible for AGN feeding, causes the diversity of AGN types, and may be an important channel for interaction with the host galaxy. The small physical scales of the dust structures means that the so-called "torus" remains unresolved with 10m-class telescopes, and instead we use the mid-infrared interferometer, VLTI MATISSE, to study a small number of nearby Seyfert AGN. The Circinus Galaxy is the nearest Seyfert 2, and using MATISSE we have imaged its circumnuclear dust for the first time. It is clear that a smooth torus is no longer a sufficient description of the dust. Instead we find a 1.9 pc diameter thin disk and patchy emission perpendicular to it. We find strong evidence of dust clumpiness and ~3pc scale warm dust emission consistent with radiation-driven outflow models. We also showed in imaging of NGC 1068 that the SMBH was obscured by a warm, nearly edge-on disk. We identified emission from polar flows and absorbing dust that is mineralogically distinct from standard ISM dust, indicating possible dust recycling. These results place new constraints on hydrodynamical and radiation transfer modeling, and have implications for the Unified Model of AGN.

2022-04-22
11:00
Classification of astronomical data using machine learning. An application to variable stars classification
Sara Jamal (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Large-scale surveys such as Gaia and the Rubin Observatory (LSST) raise the challenge of processing large data streams to identify more than 10^6 sources, thus supporting the use of automated approaches such as ML for classification tasks and outlier detection. In this context, the performances of ML techniques (e.g., neural networks) have been demonstrated over the last years in a broad range of applications such as supernovae classification, transient events detection and, more generally, VS classification.
Stellar variability manifests through changes over time in the chemical composition, the brightness and the color of a star depending on its evolutionary stage and environment (e.g. multiple system, accretion). The classification of VS is based on the taxonomy defined by the GCVS and exploits data observed over time across different photometric bands.
The first part of this talk aims to briefly present the general context supporting the use of ML for astronomical data classification, with an emphasis on VS. The second part of this talk presents my previous work on VS classification using deep neural networks, and introduces the ongoing developments of the ML classification module, DSC, for Gaia. Finally, I will close with a discussion on current limitations and outlooks regarding the use of ML for classification in astronomy.

2022-04-22
11:00
Classification of astronomical data using machine learning. An application to variable stars classification
Sara Jamal (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Large-scale surveys such as Gaia and the Rubin Observatory (LSST) raise the challenge of processing large data streams to identify more than 10^6 sources, thus supporting the use of automated approaches such as ML for classification tasks and outlier detection. In this context, the performances of ML techniques (e.g., neural networks) have been demonstrated over the last years in a broad range of applications such as supernovae classification, transient events detection and, more generally, VS classification.
Stellar variability manifests through changes over time in the chemical composition, the brightness and the color of a star depending on its evolutionary stage and environment (e.g. multiple system, accretion). The classification of VS is based on the taxonomy defined by the GCVS and exploits data observed over time across different photometric bands.
The first part of this talk aims to briefly present the general context supporting the use of ML for astronomical data classification, with an emphasis on VS. The second part of this talk presents my previous work on VS classification using deep neural networks, and introduces the ongoing developments of the ML classification module, DSC, for Gaia. Finally, I will close with a discussion on current limitations and outlooks regarding the use of ML for classification in astronomy.

2022-04-22
11:00
Classification of astronomical data using machine learning. An application to variable stars classification
Sara Jamal (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Large-scale surveys such as Gaia and the Rubin Observatory (LSST) raise the challenge of processing large data streams to identify more than 10^6 sources, thus supporting the use of automated approaches such as ML for classification tasks and outlier detection. In this context, the performances of ML techniques (e.g., neural networks) have been demonstrated over the last years in a broad range of applications such as supernovae classification, transient events detection and, more generally, VS classification.
Stellar variability manifests through changes over time in the chemical composition, the brightness and the color of a star depending on its evolutionary stage and environment (e.g. multiple system, accretion). The classification of VS is based on the taxonomy defined by the GCVS and exploits data observed over time across different photometric bands.
The first part of this talk aims to briefly present the general context supporting the use of ML for astronomical data classification, with an emphasis on VS. The second part of this talk presents my previous work on VS classification using deep neural networks, and introduces the ongoing developments of the ML classification module, DSC, for Gaia. Finally, I will close with a discussion on current limitations and outlooks regarding the use of ML for classification in astronomy.

2022-04-22
11:00
Classification of astronomical data using machine learning. An application to variable stars classification
Sara Jamal (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Large-scale surveys such as Gaia and the Rubin Observatory (LSST) raise the challenge of processing large data streams to identify more than 10^6 sources, thus supporting the use of automated approaches such as ML for classification tasks and outlier detection. In this context, the performances of ML techniques (e.g., neural networks) have been demonstrated over the last years in a broad range of applications such as supernovae classification, transient events detection and, more generally, VS classification.
Stellar variability manifests through changes over time in the chemical composition, the brightness and the color of a star depending on its evolutionary stage and environment (e.g. multiple system, accretion). The classification of VS is based on the taxonomy defined by the GCVS and exploits data observed over time across different photometric bands.
The first part of this talk aims to briefly present the general context supporting the use of ML for astronomical data classification, with an emphasis on VS. The second part of this talk presents my previous work on VS classification using deep neural networks, and introduces the ongoing developments of the ML classification module, DSC, for Gaia. Finally, I will close with a discussion on current limitations and outlooks regarding the use of ML for classification in astronomy.

2022-04-15
11:00
No KoCo
Public Holiday
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-04-15
11:00
No KoCo
Public Holiday
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-04-15
11:00
No KoCo
Public Holiday
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-04-15
11:00
No KoCo
Public Holiday
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-04-08
11:00
Unveiling the early stages of planet formation
Myriam Benisty (IPAG)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
The exoplanet population detected so far shows an extreme diversity that is still partly unexplained. It may originate from the diversity in the initial conditions and physical processes that lead to their formation in protoplanetary disks. Protoplanetary disks evolve and dissipate rapidly while planets are forming resulting in a complex interplay that can influence and determine the final outcome of the planet formation process. To address this major open question, it is crucial to directly observe young planets still in the process of formation, and their direct imprints on the disk structure.

In this talk, I will present recent high-resolution observations of protoplanetary disks, obtained at multiple wavelengths, that show that small scale structures are not only nearly ubiquitous in disks but that they can directly inform on the disk physical conditions, the underlying young planets population and the processes of planet formation. I will also discuss the exciting perspectives in this field, enabled by the development of new instrumentation.

2022-04-08
11:00
Unveiling the early stages of planet formation
Myriam Benisty (IPAG)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
The exoplanet population detected so far shows an extreme diversity that is still partly unexplained. It may originate from the diversity in the initial conditions and physical processes that lead to their formation in protoplanetary disks. Protoplanetary disks evolve and dissipate rapidly while planets are forming resulting in a complex interplay that can influence and determine the final outcome of the planet formation process. To address this major open question, it is crucial to directly observe young planets still in the process of formation, and their direct imprints on the disk structure.

In this talk, I will present recent high-resolution observations of protoplanetary disks, obtained at multiple wavelengths, that show that small scale structures are not only nearly ubiquitous in disks but that they can directly inform on the disk physical conditions, the underlying young planets population and the processes of planet formation. I will also discuss the exciting perspectives in this field, enabled by the development of new instrumentation.

2022-04-08
11:00
Unveiling the early stages of planet formation
Myriam Benisty (IPAG)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
The exoplanet population detected so far shows an extreme diversity that is still partly unexplained. It may originate from the diversity in the initial conditions and physical processes that lead to their formation in protoplanetary disks. Protoplanetary disks evolve and dissipate rapidly while planets are forming resulting in a complex interplay that can influence and determine the final outcome of the planet formation process. To address this major open question, it is crucial to directly observe young planets still in the process of formation, and their direct imprints on the disk structure.

In this talk, I will present recent high-resolution observations of protoplanetary disks, obtained at multiple wavelengths, that show that small scale structures are not only nearly ubiquitous in disks but that they can directly inform on the disk physical conditions, the underlying young planets population and the processes of planet formation. I will also discuss the exciting perspectives in this field, enabled by the development of new instrumentation.

2022-04-08
11:00
Unveiling the early stages of planet formation
Myriam Benisty (IPAG)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
The exoplanet population detected so far shows an extreme diversity that is still partly unexplained. It may originate from the diversity in the initial conditions and physical processes that lead to their formation in protoplanetary disks. Protoplanetary disks evolve and dissipate rapidly while planets are forming resulting in a complex interplay that can influence and determine the final outcome of the planet formation process. To address this major open question, it is crucial to directly observe young planets still in the process of formation, and their direct imprints on the disk structure.

In this talk, I will present recent high-resolution observations of protoplanetary disks, obtained at multiple wavelengths, that show that small scale structures are not only nearly ubiquitous in disks but that they can directly inform on the disk physical conditions, the underlying young planets population and the processes of planet formation. I will also discuss the exciting perspectives in this field, enabled by the development of new instrumentation.

2022-04-01
11:00
Warm giant exoplanets in the TESS era
Melissa Hobson (MPIA) : The WINE survey
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
In order to understand planet formation, evolution, and internal structure, we need a clear picture of exoplanet demographics. In particular, giant long-period exoplanets are fundamental, as -unlike the better-sampled Hot Jupiters - they preserve their formation history in their orbital parameters. Likewise, they do not suffer from irradiation-induced inflation as Hot Jupiters do, so their internal structure can be better modelled. The ongoing TESS mission has provided many warm giant candidates, which the Warm gIaNts with tEss collaboration (WINE) is at the forefront of detecting, confirming, and characterizing. Our systematic search for transits in the TESS light curves has given rise to hundreds of transiting giant candidates with periods larger than 10 days, out to hundreds of days. Our efficient ground-based radial-velocity and photometric follow-up of the southern skies has already confirmed several tens of these candidates. In this presentation, I will describe the survey, and present some of our most exciting recent discoveries, such as a still-cooling planet around a young, active star, and an exo-Saturn with a habitable-zone companion.

2022-04-01
11:00
Warm giant exoplanets in the TESS era
Melissa Hobson (MPIA) : The WINE survey
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
In order to understand planet formation, evolution, and internal structure, we need a clear picture of exoplanet demographics. In particular, giant long-period exoplanets are fundamental, as -unlike the better-sampled Hot Jupiters - they preserve their formation history in their orbital parameters. Likewise, they do not suffer from irradiation-induced inflation as Hot Jupiters do, so their internal structure can be better modelled. The ongoing TESS mission has provided many warm giant candidates, which the Warm gIaNts with tEss collaboration (WINE) is at the forefront of detecting, confirming, and characterizing. Our systematic search for transits in the TESS light curves has given rise to hundreds of transiting giant candidates with periods larger than 10 days, out to hundreds of days. Our efficient ground-based radial-velocity and photometric follow-up of the southern skies has already confirmed several tens of these candidates. In this presentation, I will describe the survey, and present some of our most exciting recent discoveries, such as a still-cooling planet around a young, active star, and an exo-Saturn with a habitable-zone companion.

2022-04-01
11:00
Warm giant exoplanets in the TESS era
Melissa Hobson (MPIA) : The WINE survey
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
In order to understand planet formation, evolution, and internal structure, we need a clear picture of exoplanet demographics. In particular, giant long-period exoplanets are fundamental, as -unlike the better-sampled Hot Jupiters - they preserve their formation history in their orbital parameters. Likewise, they do not suffer from irradiation-induced inflation as Hot Jupiters do, so their internal structure can be better modelled. The ongoing TESS mission has provided many warm giant candidates, which the Warm gIaNts with tEss collaboration (WINE) is at the forefront of detecting, confirming, and characterizing. Our systematic search for transits in the TESS light curves has given rise to hundreds of transiting giant candidates with periods larger than 10 days, out to hundreds of days. Our efficient ground-based radial-velocity and photometric follow-up of the southern skies has already confirmed several tens of these candidates. In this presentation, I will describe the survey, and present some of our most exciting recent discoveries, such as a still-cooling planet around a young, active star, and an exo-Saturn with a habitable-zone companion.

2022-04-01
11:00
Warm giant exoplanets in the TESS era
Melissa Hobson (MPIA) : The WINE survey
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
In order to understand planet formation, evolution, and internal structure, we need a clear picture of exoplanet demographics. In particular, giant long-period exoplanets are fundamental, as -unlike the better-sampled Hot Jupiters - they preserve their formation history in their orbital parameters. Likewise, they do not suffer from irradiation-induced inflation as Hot Jupiters do, so their internal structure can be better modelled. The ongoing TESS mission has provided many warm giant candidates, which the Warm gIaNts with tEss collaboration (WINE) is at the forefront of detecting, confirming, and characterizing. Our systematic search for transits in the TESS light curves has given rise to hundreds of transiting giant candidates with periods larger than 10 days, out to hundreds of days. Our efficient ground-based radial-velocity and photometric follow-up of the southern skies has already confirmed several tens of these candidates. In this presentation, I will describe the survey, and present some of our most exciting recent discoveries, such as a still-cooling planet around a young, active star, and an exo-Saturn with a habitable-zone companion.

2022-03-25
15:00
The interplay between internal and external processes in disk galaxies
Francesca Pinna (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Galactic internal structures are an important tracer of the global-galaxy formation and evolution. At larger scale, spatially resolved stellar populations of galactic disks tell us the story of spiral galaxies from the early stages when the older thick disks formed, to recent times when most thin disks were still forming stars. Thick disks, fainter envelopes of the brighter thin disks, are generally older and more metal-poor. Different formation scenarios have been proposed in the literature to explain their properties: in-situ formation at high redshift from turbulent gas, dynamical heating of a preexisting thinner disk and direct accretion of stars. I will present my work on this topic, making use of integral-field spectroscopy observations of edge-on galaxies as well as high-resolution numerical simulations. These results reveal complex thick-disk origins, combination of the different mechanisms that were previously proposed, and shed some light on the evolutionary connection between the thin and the thick disk. Their star-formation histories and chemical evolutions result from the interplay between internal and external processes. Galaxy mergers, providing both stars and gas from satellites, play an essential role in the formation and growth of galactic internal structures at different spatial scales, and are then key to understand the mass assembly of galaxies.

2022-03-25
15:00
The interplay between internal and external processes in disk galaxies
Francesca Pinna (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Galactic internal structures are an important tracer of the global-galaxy formation and evolution. At larger scale, spatially resolved stellar populations of galactic disks tell us the story of spiral galaxies from the early stages when the older thick disks formed, to recent times when most thin disks were still forming stars. Thick disks, fainter envelopes of the brighter thin disks, are generally older and more metal-poor. Different formation scenarios have been proposed in the literature to explain their properties: in-situ formation at high redshift from turbulent gas, dynamical heating of a preexisting thinner disk and direct accretion of stars. I will present my work on this topic, making use of integral-field spectroscopy observations of edge-on galaxies as well as high-resolution numerical simulations. These results reveal complex thick-disk origins, combination of the different mechanisms that were previously proposed, and shed some light on the evolutionary connection between the thin and the thick disk. Their star-formation histories and chemical evolutions result from the interplay between internal and external processes. Galaxy mergers, providing both stars and gas from satellites, play an essential role in the formation and growth of galactic internal structures at different spatial scales, and are then key to understand the mass assembly of galaxies.

2022-03-25
15:00
The interplay between internal and external processes in disk galaxies
Francesca Pinna (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Galactic internal structures are an important tracer of the global-galaxy formation and evolution. At larger scale, spatially resolved stellar populations of galactic disks tell us the story of spiral galaxies from the early stages when the older thick disks formed, to recent times when most thin disks were still forming stars. Thick disks, fainter envelopes of the brighter thin disks, are generally older and more metal-poor. Different formation scenarios have been proposed in the literature to explain their properties: in-situ formation at high redshift from turbulent gas, dynamical heating of a preexisting thinner disk and direct accretion of stars. I will present my work on this topic, making use of integral-field spectroscopy observations of edge-on galaxies as well as high-resolution numerical simulations. These results reveal complex thick-disk origins, combination of the different mechanisms that were previously proposed, and shed some light on the evolutionary connection between the thin and the thick disk. Their star-formation histories and chemical evolutions result from the interplay between internal and external processes. Galaxy mergers, providing both stars and gas from satellites, play an essential role in the formation and growth of galactic internal structures at different spatial scales, and are then key to understand the mass assembly of galaxies.

2022-03-25
15:00
The interplay between internal and external processes in disk galaxies
Francesca Pinna (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Galactic internal structures are an important tracer of the global-galaxy formation and evolution. At larger scale, spatially resolved stellar populations of galactic disks tell us the story of spiral galaxies from the early stages when the older thick disks formed, to recent times when most thin disks were still forming stars. Thick disks, fainter envelopes of the brighter thin disks, are generally older and more metal-poor. Different formation scenarios have been proposed in the literature to explain their properties: in-situ formation at high redshift from turbulent gas, dynamical heating of a preexisting thinner disk and direct accretion of stars. I will present my work on this topic, making use of integral-field spectroscopy observations of edge-on galaxies as well as high-resolution numerical simulations. These results reveal complex thick-disk origins, combination of the different mechanisms that were previously proposed, and shed some light on the evolutionary connection between the thin and the thick disk. Their star-formation histories and chemical evolutions result from the interplay between internal and external processes. Galaxy mergers, providing both stars and gas from satellites, play an essential role in the formation and growth of galactic internal structures at different spatial scales, and are then key to understand the mass assembly of galaxies.

2022-03-18
15:00
The cloud-scale baryon cycle across the nearby galaxy population
Melanie Chevance (ZAH/ARI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Galaxies are in constant evolution, driven by the cycle of matter within them: gas clouds assemble and collapse, stars form within them, matter and energy are redistributed in the galaxy through stellar feedback and turbulence. The physical processes driving this cycle occur on small scales but govern the evolution of entire galaxies. In turn, the large-scale evolution of galaxies across space and time directly affects the environment from which stars form. It is one of the big unanswered questions in modern astrophysics which processes drive this multi-scale cycle and what its quantitative characteristics are. I will present the first systematic characterisation of the evolutionary timeline between molecular gas clouds, stars and feedback in galaxies. I will show that star formation is fast and inefficient: gas clouds are quickly destroyed (within 1-5 Myr) by radiation and winds from the young stars born within them, limiting the efficiency of the gas-to-star conversion to 2-10%. Such measurements are key to overcome the main limitation of current simulations of galaxy formation and evolution.

2022-03-18
15:00
The cloud-scale baryon cycle across the nearby galaxy population
Melanie Chevance (ZAH/ARI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Galaxies are in constant evolution, driven by the cycle of matter within them: gas clouds assemble and collapse, stars form within them, matter and energy are redistributed in the galaxy through stellar feedback and turbulence. The physical processes driving this cycle occur on small scales but govern the evolution of entire galaxies. In turn, the large-scale evolution of galaxies across space and time directly affects the environment from which stars form. It is one of the big unanswered questions in modern astrophysics which processes drive this multi-scale cycle and what its quantitative characteristics are. I will present the first systematic characterisation of the evolutionary timeline between molecular gas clouds, stars and feedback in galaxies. I will show that star formation is fast and inefficient: gas clouds are quickly destroyed (within 1-5 Myr) by radiation and winds from the young stars born within them, limiting the efficiency of the gas-to-star conversion to 2-10%. Such measurements are key to overcome the main limitation of current simulations of galaxy formation and evolution.

2022-03-18
15:00
The cloud-scale baryon cycle across the nearby galaxy population
Melanie Chevance (ZAH/ARI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Galaxies are in constant evolution, driven by the cycle of matter within them: gas clouds assemble and collapse, stars form within them, matter and energy are redistributed in the galaxy through stellar feedback and turbulence. The physical processes driving this cycle occur on small scales but govern the evolution of entire galaxies. In turn, the large-scale evolution of galaxies across space and time directly affects the environment from which stars form. It is one of the big unanswered questions in modern astrophysics which processes drive this multi-scale cycle and what its quantitative characteristics are. I will present the first systematic characterisation of the evolutionary timeline between molecular gas clouds, stars and feedback in galaxies. I will show that star formation is fast and inefficient: gas clouds are quickly destroyed (within 1-5 Myr) by radiation and winds from the young stars born within them, limiting the efficiency of the gas-to-star conversion to 2-10%. Such measurements are key to overcome the main limitation of current simulations of galaxy formation and evolution.

2022-03-18
15:00
The cloud-scale baryon cycle across the nearby galaxy population
Melanie Chevance (ZAH/ARI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Galaxies are in constant evolution, driven by the cycle of matter within them: gas clouds assemble and collapse, stars form within them, matter and energy are redistributed in the galaxy through stellar feedback and turbulence. The physical processes driving this cycle occur on small scales but govern the evolution of entire galaxies. In turn, the large-scale evolution of galaxies across space and time directly affects the environment from which stars form. It is one of the big unanswered questions in modern astrophysics which processes drive this multi-scale cycle and what its quantitative characteristics are. I will present the first systematic characterisation of the evolutionary timeline between molecular gas clouds, stars and feedback in galaxies. I will show that star formation is fast and inefficient: gas clouds are quickly destroyed (within 1-5 Myr) by radiation and winds from the young stars born within them, limiting the efficiency of the gas-to-star conversion to 2-10%. Such measurements are key to overcome the main limitation of current simulations of galaxy formation and evolution.

2022-03-11
15:00
TBA
Francesca Pinna (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
TBA

2022-03-11
15:00
Insights into hot Jupiter atmospheres from 3D circulation models
Maria Steinrueck (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Out of all exoplanets, hot Jupiters are the most amenable to atmospheric characterization. To make sense of the growing body of observations and to better understand the atmospheres of these planets, three-dimensional models are crucial. The strong day-night temperature contrast on hot Jupiters drives a vigorous atmospheric circulation which can profoundly change atmospheric processes such as chemistry, cloud formation and haze formation. In turn, these processes have a feedback on the temperature structure and the winds. In this talk, I will highlight some examples of this interaction. First, I will talk about including disequilibrium abundances of the important infrared absorbers CH4 and CO in general circulation models (GCMs). My results show that disequilibrium CH4 and CO abundances significantly affect the thermal structure, predicted phase curves and emission spectra of hot Jupiters. I will then discuss photochemical hazes. Even though it is expected that photochemical hazes form on the daysides of many hot Jupiters, my work is the first to examine the detailed 3D distribution of photochemical hazes. I will present results on the effect of the inhomogeneous haze distribution on transmission spectra as well as how heating and cooling from hazes changes the global temperature structure and atmospheric circulation.

2022-03-11
15:00
Insights into hot Jupiter atmospheres from 3D circulation models
Maria Steinrueck (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Out of all exoplanets, hot Jupiters are the most amenable to atmospheric characterization. To make sense of the growing body of observations and to better understand the atmospheres of these planets, three-dimensional models are crucial. The strong day-night temperature contrast on hot Jupiters drives a vigorous atmospheric circulation which can profoundly change atmospheric processes such as chemistry, cloud formation and haze formation. In turn, these processes have a feedback on the temperature structure and the winds. In this talk, I will highlight some examples of this interaction. First, I will talk about including disequilibrium abundances of the important infrared absorbers CH4 and CO in general circulation models (GCMs). My results show that disequilibrium CH4 and CO abundances significantly affect the thermal structure, predicted phase curves and emission spectra of hot Jupiters. I will then discuss photochemical hazes. Even though it is expected that photochemical hazes form on the daysides of many hot Jupiters, my work is the first to examine the detailed 3D distribution of photochemical hazes. I will present results on the effect of the inhomogeneous haze distribution on transmission spectra as well as how heating and cooling from hazes changes the global temperature structure and atmospheric circulation.

2022-03-11
15:00
Insights into hot Jupiter atmospheres from 3D circulation models
Maria Steinrueck (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Out of all exoplanets, hot Jupiters are the most amenable to atmospheric characterization. To make sense of the growing body of observations and to better understand the atmospheres of these planets, three-dimensional models are crucial. The strong day-night temperature contrast on hot Jupiters drives a vigorous atmospheric circulation which can profoundly change atmospheric processes such as chemistry, cloud formation and haze formation. In turn, these processes have a feedback on the temperature structure and the winds. In this talk, I will highlight some examples of this interaction. First, I will talk about including disequilibrium abundances of the important infrared absorbers CH4 and CO in general circulation models (GCMs). My results show that disequilibrium CH4 and CO abundances significantly affect the thermal structure, predicted phase curves and emission spectra of hot Jupiters. I will then discuss photochemical hazes. Even though it is expected that photochemical hazes form on the daysides of many hot Jupiters, my work is the first to examine the detailed 3D distribution of photochemical hazes. I will present results on the effect of the inhomogeneous haze distribution on transmission spectra as well as how heating and cooling from hazes changes the global temperature structure and atmospheric circulation.

2022-03-11
15:00
Insights into hot Jupiter atmospheres from 3D circulation models
Maria Steinrueck (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Out of all exoplanets, hot Jupiters are the most amenable to atmospheric characterization. To make sense of the growing body of observations and to better understand the atmospheres of these planets, three-dimensional models are crucial. The strong day-night temperature contrast on hot Jupiters drives a vigorous atmospheric circulation which can profoundly change atmospheric processes such as chemistry, cloud formation and haze formation. In turn, these processes have a feedback on the temperature structure and the winds. In this talk, I will highlight some examples of this interaction. First, I will talk about including disequilibrium abundances of the important infrared absorbers CH4 and CO in general circulation models (GCMs). My results show that disequilibrium CH4 and CO abundances significantly affect the thermal structure, predicted phase curves and emission spectra of hot Jupiters. I will then discuss photochemical hazes. Even though it is expected that photochemical hazes form on the daysides of many hot Jupiters, my work is the first to examine the detailed 3D distribution of photochemical hazes. I will present results on the effect of the inhomogeneous haze distribution on transmission spectra as well as how heating and cooling from hazes changes the global temperature structure and atmospheric circulation.

2022-03-04
15:00
Data Science at MPIA
Iva Momcheva & Morgan Fouesneau
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
We present the newly created Data Science department at MPIA. We will first give you an overview of what means data science means in the astronomy context and present our activity plans for 2022. The department will support everyone in carrying out novel, cutting-edge research and establishing MPIA as a worldwide leader in astronomical data science by providing a platform to solidify foundational hacking & coding skills, a space to explore. develop, and share data science skills.

2022-03-04
15:00
Data Science at MPIA
Iva Momcheva & Morgan Fouesneau
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
We present the newly created Data Science department at MPIA. We will first give you an overview of what means data science means in the astronomy context and present our activity plans for 2022. The department will support everyone in carrying out novel, cutting-edge research and establishing MPIA as a worldwide leader in astronomical data science by providing a platform to solidify foundational hacking & coding skills, a space to explore. develop, and share data science skills.

2022-03-04
15:00
Data Science at MPIA
Iva Momcheva & Morgan Fouesneau
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
We present the newly created Data Science department at MPIA. We will first give you an overview of what means data science means in the astronomy context and present our activity plans for 2022. The department will support everyone in carrying out novel, cutting-edge research and establishing MPIA as a worldwide leader in astronomical data science by providing a platform to solidify foundational hacking & coding skills, a space to explore. develop, and share data science skills.

2022-03-04
15:00
Data Science at MPIA
Iva Momcheva & Morgan Fouesneau
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
We present the newly created Data Science department at MPIA. We will first give you an overview of what means data science means in the astronomy context and present our activity plans for 2022. The department will support everyone in carrying out novel, cutting-edge research and establishing MPIA as a worldwide leader in astronomical data science by providing a platform to solidify foundational hacking & coding skills, a space to explore. develop, and share data science skills.

2022-02-25
15:00
TBA
Tom Mikal-Evans (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
TBA

2022-02-18
15:00
Protoplanetary disks and the dawn of planets
Leonardo Testi (ESO)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
In the classical picture of star and planet formation, disks are expected to form as a natural consequence of core collapse to form stars. Disks are then expected to mediate the extraction of excess angular momentum during the stellar accretion phase, and to be the locus of planet formation at later times. Reality is obviously much more complicated than this one line overview: disk properties “at birth” are a complex function of the star formation environment, the problem of transport in disks is far from being fully understood, as are the initial condition and timeline for planet formation. In this talk I will discuss some of these problems, mostly focusing on the successes and limitations of our understanding of the properties of individual disks and the global evolution of disk populations. I will discuss the current evidence for early planet formation in protoplanetary disks, and the open questions related to effect of the star formation environment across the Galaxy on disk properties and evolution, which likely also affect the planet formation process.

2022-02-18
15:00
Protoplanetary disks and the dawn of planets
Leonardo Testi (ESO)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
In the classical picture of star and planet formation, disks are expected to form as a natural consequence of core collapse to form stars. Disks are then expected to mediate the extraction of excess angular momentum during the stellar accretion phase, and to be the locus of planet formation at later times. Reality is obviously much more complicated than this one line overview: disk properties “at birth” are a complex function of the star formation environment, the problem of transport in disks is far from being fully understood, as are the initial condition and timeline for planet formation. In this talk I will discuss some of these problems, mostly focusing on the successes and limitations of our understanding of the properties of individual disks and the global evolution of disk populations. I will discuss the current evidence for early planet formation in protoplanetary disks, and the open questions related to effect of the star formation environment across the Galaxy on disk properties and evolution, which likely also affect the planet formation process.

2022-02-18
15:00
Protoplanetary disks and the dawn of planets
Leonardo Testi (ESO)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
In the classical picture of star and planet formation, disks are expected to form as a natural consequence of core collapse to form stars. Disks are then expected to mediate the extraction of excess angular momentum during the stellar accretion phase, and to be the locus of planet formation at later times. Reality is obviously much more complicated than this one line overview: disk properties “at birth” are a complex function of the star formation environment, the problem of transport in disks is far from being fully understood, as are the initial condition and timeline for planet formation. In this talk I will discuss some of these problems, mostly focusing on the successes and limitations of our understanding of the properties of individual disks and the global evolution of disk populations. I will discuss the current evidence for early planet formation in protoplanetary disks, and the open questions related to effect of the star formation environment across the Galaxy on disk properties and evolution, which likely also affect the planet formation process.

2022-02-18
15:00
Protoplanetary disks and the dawn of planets
Leonardo Testi (ESO)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
In the classical picture of star and planet formation, disks are expected to form as a natural consequence of core collapse to form stars. Disks are then expected to mediate the extraction of excess angular momentum during the stellar accretion phase, and to be the locus of planet formation at later times. Reality is obviously much more complicated than this one line overview: disk properties “at birth” are a complex function of the star formation environment, the problem of transport in disks is far from being fully understood, as are the initial condition and timeline for planet formation. In this talk I will discuss some of these problems, mostly focusing on the successes and limitations of our understanding of the properties of individual disks and the global evolution of disk populations. I will discuss the current evidence for early planet formation in protoplanetary disks, and the open questions related to effect of the star formation environment across the Galaxy on disk properties and evolution, which likely also affect the planet formation process.

2022-02-11
15:00
The origin of star and planetary systems
Stefan Kraus (University of Exeter)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Most stars do not exist alone but are orbited by planets or stellar-mass companions. One of the big open questions concerns how planetary systems and multiple-star systems form and what causes the diversity in their orbital architecture and compositional characteristics. In this talk, I will outline how infrared interferometry allows us to explore the origin of this diversity, either by observing systems in the process of formation or by deducing their history from the characteristics observed in fully-formed systems. I will discuss results from our MIRC-X 6 telescope imager at CHARA, where we achieve the resolution of a 330m telescope and search for potentially planet-induced structures in the innermost astronomical unit of protoplanetary disks. In the second part, I will present the ERC-funded GAIA-BIFROST project that will measure orbital parameters, precision masses, and spin-orbit alignments for thousands of binary and planetary systems. We will build a new beam-combination instrument for ESO's VLT Interferometer, named BIFROST, that will open the short-wavelength and high spectral-resolution window at VLTI. This will allow us to measure spin-orbit alignments for wide-separation planets and binaries, providing fundamentally new insights on the dynamical processes that shape system architectures. Finally, I will highlight the prospect of using BIFROST and other future missions for exoplanet spectroscopy and for decoding the formation history of these distant worlds.

2022-02-11
15:00
The origin of star and planetary systems
Stefan Kraus (University of Exeter)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Most stars do not exist alone but are orbited by planets or stellar-mass companions. One of the big open questions concerns how planetary systems and multiple-star systems form and what causes the diversity in their orbital architecture and compositional characteristics. In this talk, I will outline how infrared interferometry allows us to explore the origin of this diversity, either by observing systems in the process of formation or by deducing their history from the characteristics observed in fully-formed systems. I will discuss results from our MIRC-X 6 telescope imager at CHARA, where we achieve the resolution of a 330m telescope and search for potentially planet-induced structures in the innermost astronomical unit of protoplanetary disks. In the second part, I will present the ERC-funded GAIA-BIFROST project that will measure orbital parameters, precision masses, and spin-orbit alignments for thousands of binary and planetary systems. We will build a new beam-combination instrument for ESO's VLT Interferometer, named BIFROST, that will open the short-wavelength and high spectral-resolution window at VLTI. This will allow us to measure spin-orbit alignments for wide-separation planets and binaries, providing fundamentally new insights on the dynamical processes that shape system architectures. Finally, I will highlight the prospect of using BIFROST and other future missions for exoplanet spectroscopy and for decoding the formation history of these distant worlds.

2022-02-11
15:00
The origin of star and planetary systems
Stefan Kraus (University of Exeter)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Most stars do not exist alone but are orbited by planets or stellar-mass companions. One of the big open questions concerns how planetary systems and multiple-star systems form and what causes the diversity in their orbital architecture and compositional characteristics. In this talk, I will outline how infrared interferometry allows us to explore the origin of this diversity, either by observing systems in the process of formation or by deducing their history from the characteristics observed in fully-formed systems. I will discuss results from our MIRC-X 6 telescope imager at CHARA, where we achieve the resolution of a 330m telescope and search for potentially planet-induced structures in the innermost astronomical unit of protoplanetary disks. In the second part, I will present the ERC-funded GAIA-BIFROST project that will measure orbital parameters, precision masses, and spin-orbit alignments for thousands of binary and planetary systems. We will build a new beam-combination instrument for ESO's VLT Interferometer, named BIFROST, that will open the short-wavelength and high spectral-resolution window at VLTI. This will allow us to measure spin-orbit alignments for wide-separation planets and binaries, providing fundamentally new insights on the dynamical processes that shape system architectures. Finally, I will highlight the prospect of using BIFROST and other future missions for exoplanet spectroscopy and for decoding the formation history of these distant worlds.

2022-02-11
15:00
TBD
Stefan Kraus (University of Exeter)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
TBD

2022-02-11
15:00
The origin of star and planetary systems
Stefan Kraus (University of Exeter)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Most stars do not exist alone but are orbited by planets or stellar-mass companions. One of the big open questions concerns how planetary systems and multiple-star systems form and what causes the diversity in their orbital architecture and compositional characteristics. In this talk, I will outline how infrared interferometry allows us to explore the origin of this diversity, either by observing systems in the process of formation or by deducing their history from the characteristics observed in fully-formed systems. I will discuss results from our MIRC-X 6 telescope imager at CHARA, where we achieve the resolution of a 330m telescope and search for potentially planet-induced structures in the innermost astronomical unit of protoplanetary disks. In the second part, I will present the ERC-funded GAIA-BIFROST project that will measure orbital parameters, precision masses, and spin-orbit alignments for thousands of binary and planetary systems. We will build a new beam-combination instrument for ESO's VLT Interferometer, named BIFROST, that will open the short-wavelength and high spectral-resolution window at VLTI. This will allow us to measure spin-orbit alignments for wide-separation planets and binaries, providing fundamentally new insights on the dynamical processes that shape system architectures. Finally, I will highlight the prospect of using BIFROST and other future missions for exoplanet spectroscopy and for decoding the formation history of these distant worlds.

2022-02-11
11:00
TBD
Stefan Kraus (University of Exeter)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2022-02-04
15:00
The mass growth in star-forming galaxies in the distant Universe
Ugne Dudzeviciute (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Roughly half of the star formation that has ever occurred was obscured
by dust, thus understanding the nature, origin, and evolution of this
dust-obscured activity in galaxies is crucial for furthering our
understanding of galaxy formation and growth. Some of the most
dust-obscured and actively star-forming galaxies at high redshift are
sub-millimetre galaxies, with star formation rates in the range
~100-1000 Mo/yr and large molecular gas reservoirs. In this talk I will
present the multi-wavelength analysis of the largest sample of ALMA
870?m-selected galaxies, which aimed to better understand the structure
of these systems and the role of the sub-millimetre bright phase in the
wider context of galaxy formation and evolution. For a more complete
view of the luminous far-infrared activity in the Universe over a wider
redshift range, I will also present a comparison to a sample of less
dust-obscured galaxies (those closer to the star-forming main-sequence)
from the deepest 450?m survey. Through studying the most dust-obscured
strongly star-forming systems, less extreme dust-obscured galaxies as
well as typical ‘main-sequence' galaxies, we were able to probe the mass
build-up across the ‘main-sequence'. The results suggest that the most
massive sub-millimetre galaxies reside in the most massive dark matter
halos that can still support efficient cooling and collapse of gas, and
that there might be differences in the processes of mass growth in
galaxies across the ‘main-sequence'.

2022-02-04
15:00
The mass growth in star-forming galaxies in the distant Universe
Ugne Dudzeviciute (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Roughly half of the star formation that has ever occurred was obscured
by dust, thus understanding the nature, origin, and evolution of this
dust-obscured activity in galaxies is crucial for furthering our
understanding of galaxy formation and growth. Some of the most
dust-obscured and actively star-forming galaxies at high redshift are
sub-millimetre galaxies, with star formation rates in the range
~100-1000 Mo/yr and large molecular gas reservoirs. In this talk I will
present the multi-wavelength analysis of the largest sample of ALMA
870?m-selected galaxies, which aimed to better understand the structure
of these systems and the role of the sub-millimetre bright phase in the
wider context of galaxy formation and evolution. For a more complete
view of the luminous far-infrared activity in the Universe over a wider
redshift range, I will also present a comparison to a sample of less
dust-obscured galaxies (those closer to the star-forming main-sequence)
from the deepest 450?m survey. Through studying the most dust-obscured
strongly star-forming systems, less extreme dust-obscured galaxies as
well as typical ‘main-sequence' galaxies, we were able to probe the mass
build-up across the ‘main-sequence'. The results suggest that the most
massive sub-millimetre galaxies reside in the most massive dark matter
halos that can still support efficient cooling and collapse of gas, and
that there might be differences in the processes of mass growth in
galaxies across the ‘main-sequence'.

2022-02-04
15:00
The mass growth in star-forming galaxies in the distant Universe
Ugne Dudzeviciute (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Roughly half of the star formation that has ever occurred was obscured
by dust, thus understanding the nature, origin, and evolution of this
dust-obscured activity in galaxies is crucial for furthering our
understanding of galaxy formation and growth. Some of the most
dust-obscured and actively star-forming galaxies at high redshift are
sub-millimetre galaxies, with star formation rates in the range
~100-1000 Mo/yr and large molecular gas reservoirs. In this talk I will
present the multi-wavelength analysis of the largest sample of ALMA
870?m-selected galaxies, which aimed to better understand the structure
of these systems and the role of the sub-millimetre bright phase in the
wider context of galaxy formation and evolution. For a more complete
view of the luminous far-infrared activity in the Universe over a wider
redshift range, I will also present a comparison to a sample of less
dust-obscured galaxies (those closer to the star-forming main-sequence)
from the deepest 450?m survey. Through studying the most dust-obscured
strongly star-forming systems, less extreme dust-obscured galaxies as
well as typical ‘main-sequence' galaxies, we were able to probe the mass
build-up across the ‘main-sequence'. The results suggest that the most
massive sub-millimetre galaxies reside in the most massive dark matter
halos that can still support efficient cooling and collapse of gas, and
that there might be differences in the processes of mass growth in
galaxies across the ‘main-sequence'.

2022-02-04
15:00
TBA
Ugne Dudzeviciute (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2022-02-04
15:00
The mass growth in star-forming galaxies in the distant Universe
Ugne Dudzeviciute (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Roughly half of the star formation that has ever occurred was obscured
by dust, thus understanding the nature, origin, and evolution of this
dust-obscured activity in galaxies is crucial for furthering our
understanding of galaxy formation and growth. Some of the most
dust-obscured and actively star-forming galaxies at high redshift are
sub-millimetre galaxies, with star formation rates in the range
~100-1000 Mo/yr and large molecular gas reservoirs. In this talk I will
present the multi-wavelength analysis of the largest sample of ALMA
870?m-selected galaxies, which aimed to better understand the structure
of these systems and the role of the sub-millimetre bright phase in the
wider context of galaxy formation and evolution. For a more complete
view of the luminous far-infrared activity in the Universe over a wider
redshift range, I will also present a comparison to a sample of less
dust-obscured galaxies (those closer to the star-forming main-sequence)
from the deepest 450?m survey. Through studying the most dust-obscured
strongly star-forming systems, less extreme dust-obscured galaxies as
well as typical ‘main-sequence' galaxies, we were able to probe the mass
build-up across the ‘main-sequence'. The results suggest that the most
massive sub-millimetre galaxies reside in the most massive dark matter
halos that can still support efficient cooling and collapse of gas, and
that there might be differences in the processes of mass growth in
galaxies across the ‘main-sequence'.

2022-01-28
15:00
TBA
Jan-Torge Schindler (Leiden Observatory)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2022-01-28
15:00
TBA
Jan-Torge Schindler (Leiden Obs./MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2022-01-28
15:00
The rise and fall of quasars
Jan-Torge Schindler (Leiden Obs./MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Quasars are the most luminous long-lived sources of light in the Universe. We understand their intense emission to be the signpost of rapid accretion of matter onto a supermassive black hole (SMBH). Empowered by wide-area optical and infrared sky surveys, the last two decades have seen rapid advances in the discovery of quasars at increasingly higher redshifts. With quasar surveys now spanning a timescale of roughly 10 billion years (z=0.3-7.6), I will review the most recent measurements of the quasar luminosity function, tracking the growth of SMBHs across cosmic time. In this context I will discuss the challenges of quasar surveys on the basis of my Extremely Luminous Quasar Survey (z=3-5) and then highlight my current efforts to provide the most precise estimate of the luminosity function at z=6 with the Pan-STARRS1 distant quasar survey. The recent increase in the number of quasars known at the highest redshifts (z>5.5) has enabled subsequent observing programs to investigate the accretion conditions and the gas properties around their central SMBHs. I will summarize the most recent insights, outline open questions and discuss how new and upcoming facilities (e.g., JWST, Euclid, LSST, …) will open a new perspective on the formation and evolution of SMBHs in the coming years.

2022-01-28
11:00
TBA
Jan-Torge Schindler (Leiden Obs./MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2022-01-21
15:00
TBD
Sascha Quanz (ETH)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2022-01-21
15:00
The direct detection of extrasolar planetary systems - motivation, challenges and opportunities
Sascha Quanz (ETH)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Since the discovery of the first extrasolar planet orbiting a Sun-like star in 1995, exoplanet science has been evolving into a highly dynamic field of modern astrophysics. Today, almost 5000 exoplanets have been confirmed and, thanks to ongoing efforts from the ground and from space, this number keeps continuously increasing. Most of the planets have been discovered via indirect techniques, such as the radial velocity and transit techniques. However, the direct detection of exoplanets is required to significantly expand the exoplanet discovery space, provide crucial links to planet formation studies, and, ultimately, test hypotheses related to exoplanet habitability and the possible existence of atmospheric biosignatures in a statistically relevant sample of objects. I will briefly discuss the challenges that need to be overcome to take a direct image or a spectrum of an exoplanet and then describe a roadmap what we can expect to learn from the direct detection of exoplanets as we go from currently available observatories (e.g., VLT and, very soon, the James Webb Space Telescope), to future observations with the ELT and, eventually, to new flagship-class space missions.

2022-01-21
11:00
TBD
Sascha Quanz (ETH)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2021-12-17
15:00
TBD
Leonardo Testi (ESO)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2021-12-17
15:00
TBD
Leonardo Testi (ESO)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2021-12-10
15:00
TBD
Heidelberg-Harvard participant (?)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2021-12-10
15:00
Finding Relativistic Stellar Explosions Using Optical Time-Domain Surveys
Anna Ho (UCB)
Königstuhl Kolloquium
Zoom,
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Abstract
Decades of observations of long-duration gamma-ray bursts (GRBs), attributed to relativistic jets launched in the collapse of massive stars, have yielded important insights on massive-star evolution, compact-object formation, and the physics of relativistic outflows. A major outstanding mystery is whether GRBs---occurring at only 0.1% of the supernova rate---simply represent the tip of the iceberg in a vast landscape of phenomena. To answer this question, with the Zwicky Transient Facility (ZTF) we are conducting a systematic exploration of the rest of the iceberg via searches for fast (hour to day) optical transients. In the past few years our searches yielded several orphan afterglows (afterglows without detected GRBs) at cosmological distances, supernovae with luminous X-ray and radio emission, and mildly relativistic explosions in dense circumstellar matter. Understanding the origin of these events and their relation to GRBs will require coordinated observations between high-cadence optical surveys, wide-field X-ray monitors, and millimeter and radio observatories. This will be possible in the next few years with the launch of the Space-based multi-band astronomical Variable Objects Monitor (SVOM), the enhanced cadence of ZTF Phase II, and sensitive millimeter-band facilities like the Atacama Large Millimeter Array (ALMA).

2021-12-10
15:00
TBD
Heidelberg-Harvard participant (?)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2021-12-03
15:00
TBD
Sara Rezaei Kh. (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2021-12-03
15:00
3D structures of the local molecular clouds and their implications for star formation
Sara Rezaei Kh. (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für ASTROLOGIE, Level 3 Lecture Hall (301)
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Abstract
The unprecedented astrometry from the Gaia mission has opened a new door to studying the solar neighbourhood in great detail. In order to get the wealth of information in this data, we have developed a state-of-the-art, three-dimensional dust mapping technique using Gaussian process, that provides detailed 3D maps of the Milky Way. We obtain the 3D positions of stars from Gaia, and their individual extinction using multi-band photometry, which are then used as the input for our model. Taking into account both distance and extinction uncertainties, together with the 3D spatial correlation between neighbouring points, we produce 3D maps of the local molecular clouds, revealing the 3D structures of individual clouds in fine detail.
In this talk, I will start by introducing dust and why it is an important component of the interstellar medium, followed by some of the most recent literature works in the field. Then I will introduce you to our Gaussian-process-based technique and its application to mapping the star-forming regions in the Milky Way. I will finish by showing some of our latest results on the important role of the 3D shape in star formation properties of the molecular clouds.

2021-11-26
15:00
Prize winners
Patzer colloquium
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2021-11-26
15:00
Prize winners
Patzer colloquium
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2021-11-26
15:00
Prize winners
Patzer colloquium
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
TBD

2021-11-26
15:00
Prize winners
Patzer colloquium
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
TBD

2021-11-26
15:00
Prize winners
Patzer colloquium
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
TBD

2021-11-19
15:00
An astrochemical modeller's view of disks, planet formation and exoplanet atmospheres
Christian Eistrup (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
(Exo)planetary science has emerged as a field since the discovery of exoplanets, and a key part of this field is understanding how exoplanets form. Such understanding requires connecting observed exoplanets with characterised atmospheric properties to the environments in which they once formed: protoplanetary disk midplanes. I also requires insights and understanding of both the physical processes of planet formation, as well as the chemical compositions of planet-forming material. Chemical kinetics is gaining growing attention as a means to model how the chemical composition of material in protoplanetary disk may evolve and change during the course of planet formation, and how such chemical evolution may manifest itself in the composition of the exoplanet atmospheres that are soon to be characterised by JWST and other current and future facilities. In this talk, I will present new insights into how this "planet formation chemistry" depends on such important factors as sizes of the dust grains in the disk midplane, and the elemental ratio (C/O) of the host star, factors which are known to varying over time, and from system to system.

2021-11-19
15:00
TBD
Christian Eistrup (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2021-11-12
15:00
The Evolution of Volatile Carbon During Planet Formation
Kamber Schwarz (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The initial composition of a giant planet's atmosphere is set by the gas disk in which it forms. In this talk I will discuss recent ALMA observations which reveal low abundances of gas phase carbon in protoplanetary disks. This volatile sequestration, i.e., the removal of molecules such as CO from the gas, can occur via chemical reprocessing into less volatile species or trapping as ice in large planetesimals. Using disk chemical modeling, I will demonstrate that under most physical conditions both chemical and physical processes likely play a role in removing carbon from the gas on short timescales. I will then present ways to test various predictions regarding mechanisms to remove gas phase carbon and the dominate volatile carbon reservoir.

2021-11-12
15:00
The Evolution of Volatile Carbon During Planet Formation
Kamber Schwarz (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The initial composition of a giant planet's atmosphere is set by the gas disk in which it forms. In this talk I will discuss recent ALMA observations which reveal low abundances of gas phase carbon in protoplanetary disks. This volatile sequestration, i.e., the removal of molecules such as CO from the gas, can occur via chemical reprocessing into less volatile species or trapping as ice in large planetesimals. Using disk chemical modeling, I will demonstrate that under most physical conditions both chemical and physical processes likely play a role in removing carbon from the gas on short timescales. I will then present ways to test various predictions regarding mechanisms to remove gas phase carbon and the dominate volatile carbon reservoir.

2021-11-05
15:00
Constraining planet formation
Bertram Bitsch (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Planet formation is a complex process, where in core-accretion models micro-meter sized dust grains grow all the way to gas giants within a few Myr during the lifetime of the protoplanetary disc. In the past, planet formation models would be judged on how good they can reproduce the observed exoplanet population in respect to their masses, radii, orbital parameters and occurrence rates. In this talk, I will first review the main ingredients for planet formation models and then discuss further methods that can be used to constrain planet formation models in more detail. In particular, I will focus on constraints from ALMA as well as on measurements of planetary atmospheric compositions and stellar abundances, opening up new avenues to constrain planet formation models.

2021-11-05
15:00
Constraining planet formation
Bertram Bitsch (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Planet formation is a complex process, where in core-accretion models micro-meter sized dust grains grow all the way to gas giants within a few Myr during the lifetime of the protoplanetary disc. In the past, planet formation models would be judged on how good they can reproduce the observed exoplanet population in respect to their masses, radii, orbital parameters and occurrence rates. In this talk, I will first review the main ingredients for planet formation models and then discuss further methods that can be used to constrain planet formation models in more detail. In particular, I will focus on constraints from ALMA as well as on measurements of planetary atmospheric compositions and stellar abundances, opening up new avenues to constrain planet formation models.

2021-10-29
15:00
Launching of astrophysical jets
Christian Fendt (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
I will present recent results of MHD simulations investigating the launching of astrophysical jets, covering both relativistic and non-relativistic flows. I will cover the topics of the 1) physical conditions at the launching point of jets, 2) the origin of the jet launching magnetic field as generated by a mean-field accretion disk dynamo, and 3) general relativistic jet launching from close to a black hole. I will start 0) with an introduction on the basic physics involved.

2021-10-29
15:00
Launching of astrophysical jets
Christian Fendt (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
I will present recent results of MHD simulations investigating the launching of astrophysical jets, covering both relativistic and non-relativistic flows. I will cover the topics of the 1) physical conditions at the launching point of jets, 2) the origin of the jet launching magnetic field as generated by a mean-field accretion disk dynamo, and 3) general relativistic jet launching from close to a black hole. I will start 0) with an introduction on the basic physics involved.

2021-10-22
15:00
TBD
Sümeyye Suri (Uni Vienna)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2021-10-22
15:00
Two decades of z>6 quasar hunt: Achievements, failures, and new hopes
Roberto Decarli (INAF-Bologna)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Since their first discovery about 20 years ago, luminous quasars at cosmic dawn have proven to be exceptional tools to investigate how massive black holes formed, how the first massive galaxies and large-scale structures assembled, and what physical processes shaped the Universe at its last phase transition (the epoch of reionization). In this talk I will review how the search for a new quasar frontier has evolved in the last twenty years, and address some of the lessons we learned so far from the discovered quasars. I will discuss some of the new and old (but lingering) open puzzles. Finally, I will provide an outlook from a biased observer's perspective on what we should expect from the field in the coming years, as new facilities offer unprecedented, exciting opportunities to study massive black holes in the infancy of galaxy formation.

2021-10-22
15:00
Two decades of z>6 quasar hunt: Achievements, failures, and new hopes
Roberto Decarli (INAF-Bologna)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Since their first discovery about 20 years ago, luminous quasars at cosmic dawn have proven to be exceptional tools to investigate how massive black holes formed, how the first massive galaxies and large-scale structures assembled, and what physical processes shaped the Universe at its last phase transition (the epoch of reionization). In this talk I will review how the search for a new quasar frontier has evolved in the last twenty years, and address some of the lessons we learned so far from the discovered quasars. I will discuss some of the new and old (but lingering) open puzzles. Finally, I will provide an outlook from a biased observer's perspective on what we should expect from the field in the coming years, as new facilities offer unprecedented, exciting opportunities to study massive black holes in the infancy of galaxy formation.

2021-10-15
15:00
Cold gas in distant galaxies
Leindert Boogaard (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Cold gas is the fuel for star formation and mapping the evolution of the cosmic molecular gas content is therefore key to our understanding of the build-up of galaxies over cosmic time. The advent of large millimeter interferometers now makes it possible to map the cold gas content of the universe in unprecedented detail. In this talk, I will present the latest results from the ALMA Spectroscopic Survey of the Hubble Ultra Deep Field (ASPECS), an ALMA large program that performed the largest three dimensional spectral-scan survey for cold gas and dust through cosmic time. I will discuss the resulting physical properties and conditions inside the cold interstellar medium of star-forming galaxies at cosmic noon, and the implications of ASPECS for the cosmic molecular gas density and the baryon cycle. I will close by discussing key steps we are working on to further refine our knowledge of cold gas in distant galaxies.

2021-10-15
15:00
Cold gas in distant galaxies
Leindert Boogaard (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Cold gas is the fuel for star formation and mapping the evolution of the cosmic molecular gas content is therefore key to our understanding of the build-up of galaxies over cosmic time. The advent of large millimeter interferometers now makes it possible to map the cold gas content of the universe in unprecedented detail. In this talk, I will present the latest results from the ALMA Spectroscopic Survey of the Hubble Ultra Deep Field (ASPECS), an ALMA large program that performed the largest three dimensional spectral-scan survey for cold gas and dust through cosmic time. I will discuss the resulting physical properties and conditions inside the cold interstellar medium of star-forming galaxies at cosmic noon, and the implications of ASPECS for the cosmic molecular gas density and the baryon cycle. I will close by discussing key steps we are working on to further refine our knowledge of cold gas in distant galaxies.

2021-10-08
15:00
TBD
Jacques Kluska (KU Leuven)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2021-10-08
15:00
TBD
Jacques Kluska (KU Leuven)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2021-10-08
15:00
Disks around evolved binaries: do they form second-generation planets?
Jacques Kluska (KU Leuven)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Most of the planets were formed around young stars. But can they form around evolved stars as well?
The origin of the diversity and complexity of the detected exoplanetary systems stems from how they form in protoplanetary disks. These disks are intensively studied around young stars thanks to the high-angular resolution provided by recent instruments (VLT, ALMA). However, similar disks are also found around evolved stars, namely post-AGB binaries, raising the exciting but yet unanswered question of second-generation planet formation.
While this question has only been tackled theoretically in the past, we have now the possibility to probe such second-generation planet formation by observations using high angular resolution instruments.
In this talk I will show the latest results of an extensive high angular resolution observing campaign of these disks using infrared interferometry at the VLTI (PIONIER, GRAVITY, MATISSE).
I will show that these disks share many similarities with protoplanetary disks around young stars.
These disks are, therefore, a unique laboratory to test planet formation scenarios in a parameter space that is unmet around young stars (e.g., short disk lifetime, high stellar luminosity, no influence from the environment).
Whether or not planet formation is possible at the end of stellar evolution, studying it in a very different parameter space will provide an unprecedented test to current planet formation theories.

2021-10-08
15:00
Disks around evolved binaries: do they form second-generation planets?
Jacques Kluska (KU Leuven)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Most of the planets were formed around young stars. But can they form around evolved stars as well?
The origin of the diversity and complexity of the detected exoplanetary systems stems from how they form in protoplanetary disks. These disks are intensively studied around young stars thanks to the high-angular resolution provided by recent instruments (VLT, ALMA). However, similar disks are also found around evolved stars, namely post-AGB binaries, raising the exciting but yet unanswered question of second-generation planet formation.
While this question has only been tackled theoretically in the past, we have now the possibility to probe such second-generation planet formation by observations using high angular resolution instruments.
In this talk I will show the latest results of an extensive high angular resolution observing campaign of these disks using infrared interferometry at the VLTI (PIONIER, GRAVITY, MATISSE).
I will show that these disks share many similarities with protoplanetary disks around young stars.
These disks are, therefore, a unique laboratory to test planet formation scenarios in a parameter space that is unmet around young stars (e.g., short disk lifetime, high stellar luminosity, no influence from the environment).
Whether or not planet formation is possible at the end of stellar evolution, studying it in a very different parameter space will provide an unprecedented test to current planet formation theories.

2021-10-01
15:00
How did large programs improve our understanding of the star formation process?
Sü Suri (Uni Vienna)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Recent observational large programs have allowed us to explore the pathways which lead to the formation of high-mass stars and their impact on the natal clouds. In the molecular cloud scales, filament fragmentation and mass accretion through networks of filaments play a key-role in the formation of high- and intermediate-mass stars. In sub-parsec scales, theoretical work predicts that high-mass stars form, similarly to their low-mass counterparts, through a disk-mediated process. In this talk, I will present results from a number of large programs carried out at CARMA, NOEMA, and SOFIA with the aim of understanding the star formation process at the scales of molecular clouds down to the scales of individual star-forming cores using high velocity and spatial resolution (sub-)mm and IR data.

2021-10-01
15:00
How did large programs improve our understanding of the star formation process?
Sü Suri (Uni Vienna)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Recent observational large programs have allowed us to explore the pathways which lead to the formation of high-mass stars and their impact on the natal clouds. In the molecular cloud scales, filament fragmentation and mass accretion through networks of filaments play a key-role in the formation of high- and intermediate-mass stars. In sub-parsec scales, theoretical work predicts that high-mass stars form, similarly to their low-mass counterparts, through a disk-mediated process. In this talk, I will present results from a number of large programs carried out at CARMA, NOEMA, and SOFIA with the aim of understanding the star formation process at the scales of molecular clouds down to the scales of individual star-forming cores using high velocity and spatial resolution (sub-)mm and IR data.

2021-09-24
15:00
TBD
Saskia Hekker (HITS)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2021-09-24
15:00
TBD
Saskia Hekker (HITS)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2021-09-24
15:00
Asteroseismology: what makes stars tick?
Saskia Hekker (HITS)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
What physical processes (i.e. energy transport, rotation, chemical mixing etc) inside a star cause the star to behave in a certain way? The surface properties of a star typically do not reveal enough information to infer these processes. Therefore, we need a window to look inside the stars. This window is provided by asteroseismology - the study of the internal structure of stars through their global oscillation modes. In this talk I will provide a brief introduction to this field and present some recent results as well as challenges we are facing.

2021-09-24
15:00
Asteroseismology: what makes stars tick?
Saskia Hekker (HITS)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
What physical processes (i.e. energy transport, rotation, chemical mixing etc) inside a star cause the star to behave in a certain way? The surface properties of a star typically do not reveal enough information to infer these processes. Therefore, we need a window to look inside the stars. This window is provided by asteroseismology - the study of the internal structure of stars through their global oscillation modes. In this talk I will provide a brief introduction to this field and present some recent results as well as challenges we are facing.

2021-08-06
15:00
The CARMENES search for exoplanets around M dwarfs: Disentangling planet signals and astrophysical noise
Stephan Stock (LSW)
Königstuhl Kolloquium
ia zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The CARMENES radial-velocity (RV) survey of 365 M dwarfs to search for exoplanet has been in operation for more than five years at the 3.5 m telescope on Calar Alto, Spain. In the first part of the talk, I will give a short overview of results in which I was involved during my Ph.D. studies and that were possible thanks to CARMENES. The RV measurements of M-dwarf stars, which rank among the most active stars in the Universe, typically contain signals related to the star's rotational activity. Stellar astrophysical noise and aliasing caused by data sampling are significant obstacles that needed to be overcome for many investigated systems in the CARMENES survey. Therefore, in the second part of the talk, I will focus on a handful of such systems. I will demonstrate that it is possible to detect and model planetary RV signals at the limit of the stellar astrophysical noise by applying rigorous statistical models, along with prior information from auxiliary data and further simulations. I will also give more details regarding the disentanglement of stellar activity and planetary signals and our approach to model them by applying a Bayesian framework and Gaussian process (GP) regression models. Despite their advantages, GP models are still very controversial in the RV community due to their intrinsic flexibility and intransparency which brings the risk to come to wrong conclusions when incorporating a GP into the modeling. As part of my Ph.D. thesis, I have investigated the properties and the performance of GP models based on numerical simulations of simulated RV data of active M dwarfs. I will present some key outcomes from these simulations as well as some guidelines, tips and tricks on how to robustly use GP models for RV and photometric time series data. My goal is to convince you that while GP models can be risky if not applied correctly (as with many other types of models), they can be extremely helpful, even necessary, in many situations leading to the fact that not accounting for the correlated noise caused by the stellar activity of the star, for example by applying a GP model, might lead to wrong conclusions about the planets in the system.

2021-08-06
15:00
The CARMENES search for exoplanets around M dwarfs: Disentangling planet signals and astrophysical noise
Stephan Stock (LSW)
Königstuhl Kolloquium
ia zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
The CARMENES radial-velocity (RV) survey of 365 M dwarfs to search for exoplanet has been in operation for more than five years at the 3.5 m telescope on Calar Alto, Spain. In the first part of the talk, I will give a short overview of results in which I was involved during my Ph.D. studies and that were possible thanks to CARMENES. The RV measurements of M-dwarf stars, which rank among the most active stars in the Universe, typically contain signals related to the star's rotational activity. Stellar astrophysical noise and aliasing caused by data sampling are significant obstacles that needed to be overcome for many investigated systems in the CARMENES survey. Therefore, in the second part of the talk, I will focus on a handful of such systems. I will demonstrate that it is possible to detect and model planetary RV signals at the limit of the stellar astrophysical noise by applying rigorous statistical models, along with prior information from auxiliary data and further simulations. I will also give more details regarding the disentanglement of stellar activity and planetary signals and our approach to model them by applying a Bayesian framework and Gaussian process (GP) regression models. Despite their advantages, GP models are still very controversial in the RV community due to their intrinsic flexibility and intransparency which brings the risk to come to wrong conclusions when incorporating a GP into the modeling. As part of my Ph.D. thesis, I have investigated the properties and the performance of GP models based on numerical simulations of simulated RV data of active M dwarfs. I will present some key outcomes from these simulations as well as some guidelines, tips and tricks on how to robustly use GP models for RV and photometric time series data. My goal is to convince you that while GP models can be risky if not applied correctly (as with many other types of models), they can be extremely helpful, even necessary, in many situations leading to the fact that not accounting for the correlated noise caused by the stellar activity of the star, for example by applying a GP model, might lead to wrong conclusions about the planets in the system.

2021-08-06
15:00
The CARMENES search for exoplanets around M dwarfs: Disentangling planet signals and astrophysical noise
Stephan Stock (LSW)
Königstuhl Kolloquium
ia zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
The CARMENES radial-velocity (RV) survey of 365 M dwarfs to search for exoplanet has been in operation for more than five years at the 3.5 m telescope on Calar Alto, Spain. In the first part of the talk, I will give a short overview of results in which I was involved during my Ph.D. studies and that were possible thanks to CARMENES. The RV measurements of M-dwarf stars, which rank among the most active stars in the Universe, typically contain signals related to the star's rotational activity. Stellar astrophysical noise and aliasing caused by data sampling are significant obstacles that needed to be overcome for many investigated systems in the CARMENES survey. Therefore, in the second part of the talk, I will focus on a handful of such systems. I will demonstrate that it is possible to detect and model planetary RV signals at the limit of the stellar astrophysical noise by applying rigorous statistical models, along with prior information from auxiliary data and further simulations. I will also give more details regarding the disentanglement of stellar activity and planetary signals and our approach to model them by applying a Bayesian framework and Gaussian process (GP) regression models. Despite their advantages, GP models are still very controversial in the RV community due to their intrinsic flexibility and intransparency which brings the risk to come to wrong conclusions when incorporating a GP into the modeling. As part of my Ph.D. thesis, I have investigated the properties and the performance of GP models based on numerical simulations of simulated RV data of active M dwarfs. I will present some key outcomes from these simulations as well as some guidelines, tips and tricks on how to robustly use GP models for RV and photometric time series data. My goal is to convince you that while GP models can be risky if not applied correctly (as with many other types of models), they can be extremely helpful, even necessary, in many situations leading to the fact that not accounting for the correlated noise caused by the stellar activity of the star, for example by applying a GP model, might lead to wrong conclusions about the planets in the system.

2021-08-06
15:00
The CARMENES search for exoplanets around M dwarfs: Disentangling planet signals and astrophysical noise
Stephan Stock (LSW)
Königstuhl Kolloquium
ia zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
The CARMENES radial-velocity (RV) survey of 365 M dwarfs to search for exoplanet has been in operation for more than five years at the 3.5 m telescope on Calar Alto, Spain. In the first part of the talk, I will give a short overview of results in which I was involved during my Ph.D. studies and that were possible thanks to CARMENES. The RV measurements of M-dwarf stars, which rank among the most active stars in the Universe, typically contain signals related to the star's rotational activity. Stellar astrophysical noise and aliasing caused by data sampling are significant obstacles that needed to be overcome for many investigated systems in the CARMENES survey. Therefore, in the second part of the talk, I will focus on a handful of such systems. I will demonstrate that it is possible to detect and model planetary RV signals at the limit of the stellar astrophysical noise by applying rigorous statistical models, along with prior information from auxiliary data and further simulations. I will also give more details regarding the disentanglement of stellar activity and planetary signals and our approach to model them by applying a Bayesian framework and Gaussian process (GP) regression models. Despite their advantages, GP models are still very controversial in the RV community due to their intrinsic flexibility and intransparency which brings the risk to come to wrong conclusions when incorporating a GP into the modeling. As part of my Ph.D. thesis, I have investigated the properties and the performance of GP models based on numerical simulations of simulated RV data of active M dwarfs. I will present some key outcomes from these simulations as well as some guidelines, tips and tricks on how to robustly use GP models for RV and photometric time series data. My goal is to convince you that while GP models can be risky if not applied correctly (as with many other types of models), they can be extremely helpful, even necessary, in many situations leading to the fact that not accounting for the correlated noise caused by the stellar activity of the star, for example by applying a GP model, might lead to wrong conclusions about the planets in the system.

2021-07-30
15:00
tbd
Stephan Stock (LSW)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2021-07-30
15:00
Picture a Scientist
Movie Screening (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2021-07-23
15:00
Star formation and feedback in low-mass molecular clouds - a 3D view
Steffi Walch-Gassner (Uni Cologne)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Star formation takes place in the densest and coldest parts of the interstellar medium (ISM), in dark molecular clouds. These are swept up by multiple supernova explosions on scales of several hundred parsec. While condensing out of the warm ISM, the clouds are continuously fed with fresh gas. Thus, the turbulent substructure and magnetic field properties are imprinted during cloud formation. The formation of dense clouds from the multi-phase ISM, the onset of star formation, and the evolution of the molecular clouds under the impact of stellar feedback from newly born massive stars is studied in high-resolution simulations within the SILCC-Zoom project.
In this talk I will show how the evolution of self-consistently formed molecular clouds is governed by stellar feedback from newly born massive stars. Our simulated molecular clouds resemble nearby molecular clouds like Taurus and Ophiuchus. We investigate how the presence of a magnetic field impacts the structure of the forming molecular clouds and find that the presence of a magnetic field leads to more fluffy clouds. In general, the detailed cloud substructure (and therefore highly localised shielding factors) determines the clouds' vulnerability to stellar feedback processes, in particular to ionizing radiation, as well as the clustering properties of the new-born stars. Moreover, we find that the ionization state of the gas can be highly variable on scales of tens of parsec due to small-scale turbulent motions within the star-forming clouds, which shield and release the ionizing radiation. Overall, the efficiency of star formation is quite effectively regulated by stellar (pre-supernova) feedback on small scales.
By means of synthetic observations, we also investigate in detail how our simulations would appear to an observer. I will show a few examples focussing on CO and ionized carbon and discussing CO-dark molecular gas.

2021-07-23
15:00
Star formation and feedback in low-mass molecular clouds - a 3D view
Steffi Walch-Gassner (Uni Cologne)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Star formation takes place in the densest and coldest parts of the interstellar medium (ISM), in dark molecular clouds. These are swept up by multiple supernova explosions on scales of several hundred parsec. While condensing out of the warm ISM, the clouds are continuously fed with fresh gas. Thus, the turbulent substructure and magnetic field properties are imprinted during cloud formation. The formation of dense clouds from the multi-phase ISM, the onset of star formation, and the evolution of the molecular clouds under the impact of stellar feedback from newly born massive stars is studied in high-resolution simulations within the SILCC-Zoom project.
In this talk I will show how the evolution of self-consistently formed molecular clouds is governed by stellar feedback from newly born massive stars. Our simulated molecular clouds resemble nearby molecular clouds like Taurus and Ophiuchus. We investigate how the presence of a magnetic field impacts the structure of the forming molecular clouds and find that the presence of a magnetic field leads to more fluffy clouds. In general, the detailed cloud substructure (and therefore highly localised shielding factors) determines the clouds' vulnerability to stellar feedback processes, in particular to ionizing radiation, as well as the clustering properties of the new-born stars. Moreover, we find that the ionization state of the gas can be highly variable on scales of tens of parsec due to small-scale turbulent motions within the star-forming clouds, which shield and release the ionizing radiation. Overall, the efficiency of star formation is quite effectively regulated by stellar (pre-supernova) feedback on small scales.
By means of synthetic observations, we also investigate in detail how our simulations would appear to an observer. I will show a few examples focussing on CO and ionized carbon and discussing CO-dark molecular gas.

2021-07-23
15:00
Star formation and feedback in low-mass molecular clouds - a 3D view
Steffi Walch-Gassner (Uni Cologne)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Star formation takes place in the densest and coldest parts of the interstellar medium (ISM), in dark molecular clouds. These are swept up by multiple supernova explosions on scales of several hundred parsec. While condensing out of the warm ISM, the clouds are continuously fed with fresh gas. Thus, the turbulent substructure and magnetic field properties are imprinted during cloud formation. The formation of dense clouds from the multi-phase ISM, the onset of star formation, and the evolution of the molecular clouds under the impact of stellar feedback from newly born massive stars is studied in high-resolution simulations within the SILCC-Zoom project.
In this talk I will show how the evolution of self-consistently formed molecular clouds is governed by stellar feedback from newly born massive stars. Our simulated molecular clouds resemble nearby molecular clouds like Taurus and Ophiuchus. We investigate how the presence of a magnetic field impacts the structure of the forming molecular clouds and find that the presence of a magnetic field leads to more fluffy clouds. In general, the detailed cloud substructure (and therefore highly localised shielding factors) determines the clouds' vulnerability to stellar feedback processes, in particular to ionizing radiation, as well as the clustering properties of the new-born stars. Moreover, we find that the ionization state of the gas can be highly variable on scales of tens of parsec due to small-scale turbulent motions within the star-forming clouds, which shield and release the ionizing radiation. Overall, the efficiency of star formation is quite effectively regulated by stellar (pre-supernova) feedback on small scales.
By means of synthetic observations, we also investigate in detail how our simulations would appear to an observer. I will show a few examples focussing on CO and ionized carbon and discussing CO-dark molecular gas.

2021-07-23
15:00
Star formation and feedback in low-mass molecular clouds - a 3D view
Steffi Walch-Gassner (Uni Cologne)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Star formation takes place in the densest and coldest parts of the interstellar medium (ISM), in dark molecular clouds. These are swept up by multiple supernova explosions on scales of several hundred parsec. While condensing out of the warm ISM, the clouds are continuously fed with fresh gas. Thus, the turbulent substructure and magnetic field properties are imprinted during cloud formation. The formation of dense clouds from the multi-phase ISM, the onset of star formation, and the evolution of the molecular clouds under the impact of stellar feedback from newly born massive stars is studied in high-resolution simulations within the SILCC-Zoom project.
In this talk I will show how the evolution of self-consistently formed molecular clouds is governed by stellar feedback from newly born massive stars. Our simulated molecular clouds resemble nearby molecular clouds like Taurus and Ophiuchus. We investigate how the presence of a magnetic field impacts the structure of the forming molecular clouds and find that the presence of a magnetic field leads to more fluffy clouds. In general, the detailed cloud substructure (and therefore highly localised shielding factors) determines the clouds' vulnerability to stellar feedback processes, in particular to ionizing radiation, as well as the clustering properties of the new-born stars. Moreover, we find that the ionization state of the gas can be highly variable on scales of tens of parsec due to small-scale turbulent motions within the star-forming clouds, which shield and release the ionizing radiation. Overall, the efficiency of star formation is quite effectively regulated by stellar (pre-supernova) feedback on small scales.
By means of synthetic observations, we also investigate in detail how our simulations would appear to an observer. I will show a few examples focussing on CO and ionized carbon and discussing CO-dark molecular gas.

2021-07-16
15:00
New Ideas in Instrument Calibration
David Hogg (NYU/MPIA/Flatiron Institute)
Königstuhl Kolloquium
ia zoom link. Please contact organisers if you need the zoom information.,
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Abstract
In many contexts in astrophysics we are faced with instrument-calibration problems where precision (or accuracy) are of utmost importance\; these include imagers, spectrographs, and interferometers. I will discuss a few new and important ideas in calibration including (a) self-calibration, in which the scientific data of interest are used to directly determine calibration parameters, (b) cross-calibration, in which a poorly calibrated instrument is calibrated by comparing the science data with observations made at another instrument, and (c) hierarchical (or causal) models, in which the calibration state for one observation is determined not just from nearby (in time) calibration data but instead from combining all data ever taken with the instrument into a data-driven model of the instrument's behavior. I discuss all of these ideas in the context of extreme precision star and planet projects (think radial velocities, transits and transit spectroscopy, and detailed abundances) but the ideas apply across all kinds of astronomical instrumentation, catalogs, and projects. I'll give examples in which we substantially improved precision-measurement projects.

2021-07-16
15:00
New Ideas in Instrument Calibration
David Hogg (NYU/MPIA/Flatiron Institute)
Königstuhl Kolloquium
ia zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
In many contexts in astrophysics we are faced with instrument-calibration problems where precision (or accuracy) are of utmost importance\; these include imagers, spectrographs, and interferometers. I will discuss a few new and important ideas in calibration including (a) self-calibration, in which the scientific data of interest are used to directly determine calibration parameters, (b) cross-calibration, in which a poorly calibrated instrument is calibrated by comparing the science data with observations made at another instrument, and (c) hierarchical (or causal) models, in which the calibration state for one observation is determined not just from nearby (in time) calibration data but instead from combining all data ever taken with the instrument into a data-driven model of the instrument's behavior. I discuss all of these ideas in the context of extreme precision star and planet projects (think radial velocities, transits and transit spectroscopy, and detailed abundances) but the ideas apply across all kinds of astronomical instrumentation, catalogs, and projects. I'll give examples in which we substantially improved precision-measurement projects.

2021-07-16
15:00
New Ideas in Instrument Calibration
David Hogg (NYU/MPIA/Flatiron Institute)
Königstuhl Kolloquium
ia zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
In many contexts in astrophysics we are faced with instrument-calibration problems where precision (or accuracy) are of utmost importance\; these include imagers, spectrographs, and interferometers. I will discuss a few new and important ideas in calibration including (a) self-calibration, in which the scientific data of interest are used to directly determine calibration parameters, (b) cross-calibration, in which a poorly calibrated instrument is calibrated by comparing the science data with observations made at another instrument, and (c) hierarchical (or causal) models, in which the calibration state for one observation is determined not just from nearby (in time) calibration data but instead from combining all data ever taken with the instrument into a data-driven model of the instrument's behavior. I discuss all of these ideas in the context of extreme precision star and planet projects (think radial velocities, transits and transit spectroscopy, and detailed abundances) but the ideas apply across all kinds of astronomical instrumentation, catalogs, and projects. I'll give examples in which we substantially improved precision-measurement projects.

2021-07-16
15:00
New Ideas in Instrument Calibration
David Hogg (NYU/MPIA/Flatiron Institute)
Königstuhl Kolloquium
ia zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
In many contexts in astrophysics we are faced with instrument-calibration problems where precision (or accuracy) are of utmost importance\; these include imagers, spectrographs, and interferometers. I will discuss a few new and important ideas in calibration including (a) self-calibration, in which the scientific data of interest are used to directly determine calibration parameters, (b) cross-calibration, in which a poorly calibrated instrument is calibrated by comparing the science data with observations made at another instrument, and (c) hierarchical (or causal) models, in which the calibration state for one observation is determined not just from nearby (in time) calibration data but instead from combining all data ever taken with the instrument into a data-driven model of the instrument's behavior. I discuss all of these ideas in the context of extreme precision star and planet projects (think radial velocities, transits and transit spectroscopy, and detailed abundances) but the ideas apply across all kinds of astronomical instrumentation, catalogs, and projects. I'll give examples in which we substantially improved precision-measurement projects.

2021-07-09
15:00
R-process: connecting simulations to observations
Almudena Arcones (Uni. Darmstadt)
Königstuhl Kolloquium
ia zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The heaviest elements form by the rapid neutron capture process (r-process) in neutron star mergers and rare core-collapse supernovae. The light curve of the kilonova following the neutron star merger GW170817 showed indications of heavy elements being produced and direct observation of Strontium. This talk will report on recent breakthroughs in understanding the extreme environment in which the formation of the heavy elements occurs, as well as open questions regarding the astrophysics and nuclear physics involved.

2021-07-09
15:00
R-process: connecting simulations to observations
Almudena Arcones (Uni. Darmstadt)
Königstuhl Kolloquium
ia zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
The heaviest elements form by the rapid neutron capture process (r-process) in neutron star mergers and rare core-collapse supernovae. The light curve of the kilonova following the neutron star merger GW170817 showed indications of heavy elements being produced and direct observation of Strontium. This talk will report on recent breakthroughs in understanding the extreme environment in which the formation of the heavy elements occurs, as well as open questions regarding the astrophysics and nuclear physics involved.

2021-07-09
15:00
R-process: connecting simulations to observations
Almudena Arcones (Uni. Darmstadt)
Königstuhl Kolloquium
ia zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
The heaviest elements form by the rapid neutron capture process (r-process) in neutron star mergers and rare core-collapse supernovae. The light curve of the kilonova following the neutron star merger GW170817 showed indications of heavy elements being produced and direct observation of Strontium. This talk will report on recent breakthroughs in understanding the extreme environment in which the formation of the heavy elements occurs, as well as open questions regarding the astrophysics and nuclear physics involved.

2021-07-09
15:00
R-process: connecting simulations to observations
Almudena Arcones (Uni. Darmstadt)
Königstuhl Kolloquium
ia zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
The heaviest elements form by the rapid neutron capture process (r-process) in neutron star mergers and rare core-collapse supernovae. The light curve of the kilonova following the neutron star merger GW170817 showed indications of heavy elements being produced and direct observation of Strontium. This talk will report on recent breakthroughs in understanding the extreme environment in which the formation of the heavy elements occurs, as well as open questions regarding the astrophysics and nuclear physics involved.

2021-07-02
15:00
Solids in planet forming disks ? What have we learned after 10 years of ALMA?
Til Birnstiel (LMU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Despite a wealth of observations from exoplanets and our own solar system, fundamental questions remain about how planets form. Most of planet formation happens well hidden in circumstellar disks and only within the last decade, ALMA and SPHERE started to give us glimpses into the detailed structure of disks and their population properties. In this talk I will introduce the key concepts of how the solid material in disks evolves and how we can observe these processes. I will discuss how high resolution studies on the one hand and lower resolution surveys on the other hand can shed some light on the earliest stages of planet formation and which new questions have emerged.

2021-07-02
15:00
Solids in planet forming disks ? What have we learned after 10 years of ALMA?
Til Birnstiel (LMU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Despite a wealth of observations from exoplanets and our own solar system, fundamental questions remain about how planets form. Most of planet formation happens well hidden in circumstellar disks and only within the last decade, ALMA and SPHERE started to give us glimpses into the detailed structure of disks and their population properties. In this talk I will introduce the key concepts of how the solid material in disks evolves and how we can observe these processes. I will discuss how high resolution studies on the one hand and lower resolution surveys on the other hand can shed some light on the earliest stages of planet formation and which new questions have emerged.

2021-07-02
15:00
Solids in planet forming disks ? What have we learned after 10 years of ALMA?
Til Birnstiel (LMU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Despite a wealth of observations from exoplanets and our own solar system, fundamental questions remain about how planets form. Most of planet formation happens well hidden in circumstellar disks and only within the last decade, ALMA and SPHERE started to give us glimpses into the detailed structure of disks and their population properties. In this talk I will introduce the key concepts of how the solid material in disks evolves and how we can observe these processes. I will discuss how high resolution studies on the one hand and lower resolution surveys on the other hand can shed some light on the earliest stages of planet formation and which new questions have emerged.

2021-07-02
15:00
Solids in planet forming disks ? What have we learned after 10 years of ALMA?
Til Birnstiel (LMU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Despite a wealth of observations from exoplanets and our own solar system, fundamental questions remain about how planets form. Most of planet formation happens well hidden in circumstellar disks and only within the last decade, ALMA and SPHERE started to give us glimpses into the detailed structure of disks and their population properties. In this talk I will introduce the key concepts of how the solid material in disks evolves and how we can observe these processes. I will discuss how high resolution studies on the one hand and lower resolution surveys on the other hand can shed some light on the earliest stages of planet formation and which new questions have emerged.

2021-06-25
15:00
The Many Diverse Manifestations of Supermassive Black-Hole Feedback
Annalisa Pillepich (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Feedback from super massive black holes (SMBHs) is commonly invoked in state-of-the-art large-scale cosmological galaxy simulations to halt star formation in massive galaxies. In fact, no other mechanism so far has been shown to be capable of returning entire populations of simulated massive quenched galaxies that are consistent with the observed galaxy red sequence and quenched fractions. In this talk, I will show how the IllustrisTNG cosmological simulations of galaxies allow us to gain insights and testable predictions on the manifestations of these energetic phenomena. With IllustrisTNG, with one unique set of physical ingredients, we simultaneously resolve and model the inner structural details of thousands of galaxies across five orders of magnitude in stellar mass, across environments, and together with the evolution and dynamics of the inter-stellar, circum-galactic and inter-galactic media. We are putting together ever more quantitative and plausible evidences as to the role that feedback from SMBH can have, not only in shaping galaxy structural properties and galaxy populations across 90 per cent of the Universe's history, but also in regulating the thermodynamical, ionization, and metal enrichment properties of the cosmic gas across halo scales and beyond. In particular, I will show how the IllustrisTNG model predicts that the gaseous atmospheres within and around galaxies are X-ray *brighter* for star-forming than for quiescent galaxies at the transitional mass scale of ~10^10-11 solar masses. I will discuss how novel results on the observed quenched fractions from SDSS support the ejective character of SMBH feedback from the central galaxies in groups and clusters at low redshift. And finally I will show that the TNG50 simulation naturally returns X-ray emitting bubbles that resemble the eROSITA and Fermi bubbles observed at the center of our Galaxy.

2021-06-25
15:00
The Many Diverse Manifestations of Supermassive Black-Hole Feedback
Annalisa Pillepich (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
Feedback from super massive black holes (SMBHs) is commonly invoked in state-of-the-art large-scale cosmological galaxy simulations to halt star formation in massive galaxies. In fact, no other mechanism so far has been shown to be capable of returning entire populations of simulated massive quenched galaxies that are consistent with the observed galaxy red sequence and quenched fractions. In this talk, I will show how the IllustrisTNG cosmological simulations of galaxies allow us to gain insights and testable predictions on the manifestations of these energetic phenomena. With IllustrisTNG, with one unique set of physical ingredients, we simultaneously resolve and model the inner structural details of thousands of galaxies across five orders of magnitude in stellar mass, across environments, and together with the evolution and dynamics of the inter-stellar, circum-galactic and inter-galactic media. We are putting together ever more quantitative and plausible evidences as to the role that feedback from SMBH can have, not only in shaping galaxy structural properties and galaxy populations across 90 per cent of the Universe's history, but also in regulating the thermodynamical, ionization, and metal enrichment properties of the cosmic gas across halo scales and beyond. In particular, I will show how the IllustrisTNG model predicts that the gaseous atmospheres within and around galaxies are X-ray *brighter* for star-forming than for quiescent galaxies at the transitional mass scale of ~10^10-11 solar masses. I will discuss how novel results on the observed quenched fractions from SDSS support the ejective character of SMBH feedback from the central galaxies in groups and clusters at low redshift. And finally I will show that the TNG50 simulation naturally returns X-ray emitting bubbles that resemble the eROSITA and Fermi bubbles observed at the center of our Galaxy.

2021-06-25
15:00
The Many Diverse Manifestations of Supermassive Black-Hole Feedback
Annalisa Pillepich (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
Feedback from super massive black holes (SMBHs) is commonly invoked in state-of-the-art large-scale cosmological galaxy simulations to halt star formation in massive galaxies. In fact, no other mechanism so far has been shown to be capable of returning entire populations of simulated massive quenched galaxies that are consistent with the observed galaxy red sequence and quenched fractions. In this talk, I will show how the IllustrisTNG cosmological simulations of galaxies allow us to gain insights and testable predictions on the manifestations of these energetic phenomena. With IllustrisTNG, with one unique set of physical ingredients, we simultaneously resolve and model the inner structural details of thousands of galaxies across five orders of magnitude in stellar mass, across environments, and together with the evolution and dynamics of the inter-stellar, circum-galactic and inter-galactic media. We are putting together ever more quantitative and plausible evidences as to the role that feedback from SMBH can have, not only in shaping galaxy structural properties and galaxy populations across 90 per cent of the Universe's history, but also in regulating the thermodynamical, ionization, and metal enrichment properties of the cosmic gas across halo scales and beyond. In particular, I will show how the IllustrisTNG model predicts that the gaseous atmospheres within and around galaxies are X-ray *brighter* for star-forming than for quiescent galaxies at the transitional mass scale of ~10^10-11 solar masses. I will discuss how novel results on the observed quenched fractions from SDSS support the ejective character of SMBH feedback from the central galaxies in groups and clusters at low redshift. And finally I will show that the TNG50 simulation naturally returns X-ray emitting bubbles that resemble the eROSITA and Fermi bubbles observed at the center of our Galaxy.

2021-06-25
15:00
The Many Diverse Manifestations of Supermassive Black-Hole Feedback
Annalisa Pillepich (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
Feedback from super massive black holes (SMBHs) is commonly invoked in state-of-the-art large-scale cosmological galaxy simulations to halt star formation in massive galaxies. In fact, no other mechanism so far has been shown to be capable of returning entire populations of simulated massive quenched galaxies that are consistent with the observed galaxy red sequence and quenched fractions. In this talk, I will show how the IllustrisTNG cosmological simulations of galaxies allow us to gain insights and testable predictions on the manifestations of these energetic phenomena. With IllustrisTNG, with one unique set of physical ingredients, we simultaneously resolve and model the inner structural details of thousands of galaxies across five orders of magnitude in stellar mass, across environments, and together with the evolution and dynamics of the inter-stellar, circum-galactic and inter-galactic media. We are putting together ever more quantitative and plausible evidences as to the role that feedback from SMBH can have, not only in shaping galaxy structural properties and galaxy populations across 90 per cent of the Universe's history, but also in regulating the thermodynamical, ionization, and metal enrichment properties of the cosmic gas across halo scales and beyond. In particular, I will show how the IllustrisTNG model predicts that the gaseous atmospheres within and around galaxies are X-ray *brighter* for star-forming than for quiescent galaxies at the transitional mass scale of ~10^10-11 solar masses. I will discuss how novel results on the observed quenched fractions from SDSS support the ejective character of SMBH feedback from the central galaxies in groups and clusters at low redshift. And finally I will show that the TNG50 simulation naturally returns X-ray emitting bubbles that resemble the eROSITA and Fermi bubbles observed at the center of our Galaxy.

2021-06-18
15:00
The architectures of planetary systems: Population synthesis meets observations
Martin Schlecker (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Exoplanets are now routinely detected and their properties, such as their mass and orbital periods, can be constrained to high precision. While it is widely recognized that multiple planets per system are common, their mutual relationships are still largely unexplored. By confronting simulated planet populations with observed exoplanets, I will show that planetary properties and the architectures of their host planetary systems are related, and, more specifically, that observables of small planets on short orbits might be used to infer the existence of additional planetary companions. I will discuss how a solidification of this prediction has the power to constrain central open questions in contemporary planet formation theory, ranging from the efficiency of pebble accretion to planet migration.

2021-06-18
15:00
The architectures of planetary systems: Population synthesis meets observations
Martin Schlecker (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Exoplanets are now routinely detected and their properties, such as their mass and orbital periods, can be constrained to high precision. While it is widely recognized that multiple planets per system are common, their mutual relationships are still largely unexplored. By confronting simulated planet populations with observed exoplanets, I will show that planetary properties and the architectures of their host planetary systems are related, and, more specifically, that observables of small planets on short orbits might be used to infer the existence of additional planetary companions. I will discuss how a solidification of this prediction has the power to constrain central open questions in contemporary planet formation theory, ranging from the efficiency of pebble accretion to planet migration.

2021-06-18
15:00
The architectures of planetary systems: Population synthesis meets observations
Martin Schlecker (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Exoplanets are now routinely detected and their properties, such as their mass and orbital periods, can be constrained to high precision. While it is widely recognized that multiple planets per system are common, their mutual relationships are still largely unexplored. By confronting simulated planet populations with observed exoplanets, I will show that planetary properties and the architectures of their host planetary systems are related, and, more specifically, that observables of small planets on short orbits might be used to infer the existence of additional planetary companions. I will discuss how a solidification of this prediction has the power to constrain central open questions in contemporary planet formation theory, ranging from the efficiency of pebble accretion to planet migration.

2021-06-18
15:00
The architectures of planetary systems: Population synthesis meets observations
Martin Schlecker (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Exoplanets are now routinely detected and their properties, such as their mass and orbital periods, can be constrained to high precision. While it is widely recognized that multiple planets per system are common, their mutual relationships are still largely unexplored. By confronting simulated planet populations with observed exoplanets, I will show that planetary properties and the architectures of their host planetary systems are related, and, more specifically, that observables of small planets on short orbits might be used to infer the existence of additional planetary companions. I will discuss how a solidification of this prediction has the power to constrain central open questions in contemporary planet formation theory, ranging from the efficiency of pebble accretion to planet migration.

2021-06-11
15:00
High resolution observations of protoplanetary disk structures
Myriam Benisty (IPAG)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract

Recent observing campaigns have revealed a great diversity in exoplanetary systems whose origin is yet to be understood. How and when planets form, and how they evolve and interact with their birth environment, the protoplanetary disks, are major open questions. Protoplanetary disks evolve and dissipate rapidly while planets are forming, implying a direct feedback between the processes of planet formation and disk evolution. These mechanisms leave clear imprints on the disk structure that can be directly observed. In the past few years, high-resolution observations of protoplanetary disks obtained in the infrared and in the millimeter regime have led to exquisite images and shown that small scale structures are ubiquitous in protoplanetary disks. I will present recent observational results on protoplanetary disks obtained with VLTI, VLT/SPHERE and ALMA, that allow to probe the disk structure and the dynamics of solids, and in particular, in the so far unique system that hosts two directly imaged protoplanets.


2021-06-11
15:00
High resolution observations of protoplanetary disk structures
Myriam Benisty (IPAG)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract

Recent observing campaigns have revealed a great diversity in exoplanetary systems whose origin is yet to be understood. How and when planets form, and how they evolve and interact with their birth environment, the protoplanetary disks, are major open questions. Protoplanetary disks evolve and dissipate rapidly while planets are forming, implying a direct feedback between the processes of planet formation and disk evolution. These mechanisms leave clear imprints on the disk structure that can be directly observed. In the past few years, high-resolution observations of protoplanetary disks obtained in the infrared and in the millimeter regime have led to exquisite images and shown that small scale structures are ubiquitous in protoplanetary disks. I will present recent observational results on protoplanetary disks obtained with VLTI, VLT/SPHERE and ALMA, that allow to probe the disk structure and the dynamics of solids, and in particular, in the so far unique system that hosts two directly imaged protoplanets.


2021-06-11
15:00
High resolution observations of protoplanetary disk structures
Myriam Benisty (IPAG)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract

Recent observing campaigns have revealed a great diversity in exoplanetary systems whose origin is yet to be understood. How and when planets form, and how they evolve and interact with their birth environment, the protoplanetary disks, are major open questions. Protoplanetary disks evolve and dissipate rapidly while planets are forming, implying a direct feedback between the processes of planet formation and disk evolution. These mechanisms leave clear imprints on the disk structure that can be directly observed. In the past few years, high-resolution observations of protoplanetary disks obtained in the infrared and in the millimeter regime have led to exquisite images and shown that small scale structures are ubiquitous in protoplanetary disks. I will present recent observational results on protoplanetary disks obtained with VLTI, VLT/SPHERE and ALMA, that allow to probe the disk structure and the dynamics of solids, and in particular, in the so far unique system that hosts two directly imaged protoplanets.


2021-06-11
15:00
High resolution observations of protoplanetary disk structures
Myriam Benisty (IPAG)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract

Recent observing campaigns have revealed a great diversity in exoplanetary systems whose origin is yet to be understood. How and when planets form, and how they evolve and interact with their birth environment, the protoplanetary disks, are major open questions. Protoplanetary disks evolve and dissipate rapidly while planets are forming, implying a direct feedback between the processes of planet formation and disk evolution. These mechanisms leave clear imprints on the disk structure that can be directly observed. In the past few years, high-resolution observations of protoplanetary disks obtained in the infrared and in the millimeter regime have led to exquisite images and shown that small scale structures are ubiquitous in protoplanetary disks. I will present recent observational results on protoplanetary disks obtained with VLTI, VLT/SPHERE and ALMA, that allow to probe the disk structure and the dynamics of solids, and in particular, in the so far unique system that hosts two directly imaged protoplanets.


2021-06-04
15:00
Probing the Growth of Black Holes at the Limit of Large Telescopes
Felix Bosco (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
In recent years, more and more observational evidence for the existence of black holes (BHs) was gathered. This was acknowledged by the Nobel prizes in 2017 and 2020, for the detection of gravitational waves, emitted by merging BH binaries, and for the discovery of Sag A* as the central supermassive BH (SMBH) in the Milky Way. Still, direct kinematical measurements of BH masses require to resolve the sphere of influence at sub-milliarcsecond scales. In this talk, I present. two novel observational approaches that exhaust the resolution limit of modern large telescopes in order to allow for tighter constraints on masses and growth mechanisms of BHs:

The first approach applies holographic speckle imaging techniques to near-infrared images after partial atmospheric turbulence correction. Based on simulations and observational data, we have shown that the combination of techniques recovers the diffraction limit of 8 m-class telescopes for stars too faint for classical speckle imaging. This approach will allow for tracing BHs directly via stellar kinematics.

The second technique uses the spectroastrometric signal of the quasar broad emission line region in order to constrain its geometric and kinematic structure. We extract this signal from adaptive-optics-assisted near-infrared spectroscopy with an 8m telescope and carefully study the uncertainties. The comparison of the data to our model allows us to report on the first tentative detection of the spectroastrometric signal of a luminous quasar and thereby for constraining its BH mass, the first direct measurement beyond a redshift of z = 2 and out of the detection range of reverberation mapping or optical interferometry.

2021-06-04
15:00
Probing the Growth of Black Holes at the Limit of Large Telescopes
Felix Bosco (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
In recent years, more and more observational evidence for the existence of black holes (BHs) was gathered. This was acknowledged by the Nobel prizes in 2017 and 2020, for the detection of gravitational waves, emitted by merging BH binaries, and for the discovery of Sag A* as the central supermassive BH (SMBH) in the Milky Way. Still, direct kinematical measurements of BH masses require to resolve the sphere of influence at sub-milliarcsecond scales. In this talk, I present. two novel observational approaches that exhaust the resolution limit of modern large telescopes in order to allow for tighter constraints on masses and growth mechanisms of BHs:

The first approach applies holographic speckle imaging techniques to near-infrared images after partial atmospheric turbulence correction. Based on simulations and observational data, we have shown that the combination of techniques recovers the diffraction limit of 8 m-class telescopes for stars too faint for classical speckle imaging. This approach will allow for tracing BHs directly via stellar kinematics.

The second technique uses the spectroastrometric signal of the quasar broad emission line region in order to constrain its geometric and kinematic structure. We extract this signal from adaptive-optics-assisted near-infrared spectroscopy with an 8m telescope and carefully study the uncertainties. The comparison of the data to our model allows us to report on the first tentative detection of the spectroastrometric signal of a luminous quasar and thereby for constraining its BH mass, the first direct measurement beyond a redshift of z = 2 and out of the detection range of reverberation mapping or optical interferometry.

2021-06-04
15:00
Probing the Growth of Black Holes at the Limit of Large Telescopes
Felix Bosco (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
In recent years, more and more observational evidence for the existence of black holes (BHs) was gathered. This was acknowledged by the Nobel prizes in 2017 and 2020, for the detection of gravitational waves, emitted by merging BH binaries, and for the discovery of Sag A* as the central supermassive BH (SMBH) in the Milky Way. Still, direct kinematical measurements of BH masses require to resolve the sphere of influence at sub-milliarcsecond scales. In this talk, I present. two novel observational approaches that exhaust the resolution limit of modern large telescopes in order to allow for tighter constraints on masses and growth mechanisms of BHs:

The first approach applies holographic speckle imaging techniques to near-infrared images after partial atmospheric turbulence correction. Based on simulations and observational data, we have shown that the combination of techniques recovers the diffraction limit of 8 m-class telescopes for stars too faint for classical speckle imaging. This approach will allow for tracing BHs directly via stellar kinematics.

The second technique uses the spectroastrometric signal of the quasar broad emission line region in order to constrain its geometric and kinematic structure. We extract this signal from adaptive-optics-assisted near-infrared spectroscopy with an 8m telescope and carefully study the uncertainties. The comparison of the data to our model allows us to report on the first tentative detection of the spectroastrometric signal of a luminous quasar and thereby for constraining its BH mass, the first direct measurement beyond a redshift of z = 2 and out of the detection range of reverberation mapping or optical interferometry.

2021-06-04
15:00
Probing the Growth of Black Holes at the Limit of Large Telescopes
Felix Bosco (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
In recent years, more and more observational evidence for the existence of black holes (BHs) was gathered. This was acknowledged by the Nobel prizes in 2017 and 2020, for the detection of gravitational waves, emitted by merging BH binaries, and for the discovery of Sag A* as the central supermassive BH (SMBH) in the Milky Way. Still, direct kinematical measurements of BH masses require to resolve the sphere of influence at sub-milliarcsecond scales. In this talk, I present. two novel observational approaches that exhaust the resolution limit of modern large telescopes in order to allow for tighter constraints on masses and growth mechanisms of BHs:

The first approach applies holographic speckle imaging techniques to near-infrared images after partial atmospheric turbulence correction. Based on simulations and observational data, we have shown that the combination of techniques recovers the diffraction limit of 8 m-class telescopes for stars too faint for classical speckle imaging. This approach will allow for tracing BHs directly via stellar kinematics.

The second technique uses the spectroastrometric signal of the quasar broad emission line region in order to constrain its geometric and kinematic structure. We extract this signal from adaptive-optics-assisted near-infrared spectroscopy with an 8m telescope and carefully study the uncertainties. The comparison of the data to our model allows us to report on the first tentative detection of the spectroastrometric signal of a luminous quasar and thereby for constraining its BH mass, the first direct measurement beyond a redshift of z = 2 and out of the detection range of reverberation mapping or optical interferometry.

2021-05-28
15:00
Better together: binary stars as probes of stellar evolution and fundamental physics
Kareem Al-Badry (Berkeley,MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract


Binary stars are foundational to modern astrophysics. They underpin precision measurements of stellar structure, age, and composition\; they provide the most stringent tests of general relativity, they make possible the study of faint and rare objects such as black holes and neutron stars, and they are the progenitors of gravitational wave sources. The components of binaries often interact, dramatically changing their evolution and giving rise to a spectacular zoo of astrophysical phenomenology. To understand stars -- particularly massive stars -- it is necessary to understand binaries. Large-scale stellar surveys such as Gaia, TESS, and SDSS-V are transforming the binary field, making possible both comprehensive population demographics and the discovery of rare objects. I will discuss new insights gleaned from surveys in recent years, including the creation of stripped-envelope stars following binary mass transfer, the formation of equal-mass "twin" binaries in circumbinary disks, the metallicity-dependence of the binary fraction, and the discovery of planets in binaries. I will focus in particular on the search for dormant stellar-mass black holes in binaries, discussing recent candidates and the path forward to characterizing the detached black hole population.

2021-05-28
15:00
Better together: binary stars as probes of stellar evolution and fundamental physics
Kareem Al-Badry (Berkeley,MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract


Binary stars are foundational to modern astrophysics. They underpin precision measurements of stellar structure, age, and composition\; they provide the most stringent tests of general relativity, they make possible the study of faint and rare objects such as black holes and neutron stars, and they are the progenitors of gravitational wave sources. The components of binaries often interact, dramatically changing their evolution and giving rise to a spectacular zoo of astrophysical phenomenology. To understand stars -- particularly massive stars -- it is necessary to understand binaries. Large-scale stellar surveys such as Gaia, TESS, and SDSS-V are transforming the binary field, making possible both comprehensive population demographics and the discovery of rare objects. I will discuss new insights gleaned from surveys in recent years, including the creation of stripped-envelope stars following binary mass transfer, the formation of equal-mass "twin" binaries in circumbinary disks, the metallicity-dependence of the binary fraction, and the discovery of planets in binaries. I will focus in particular on the search for dormant stellar-mass black holes in binaries, discussing recent candidates and the path forward to characterizing the detached black hole population.

2021-05-28
15:00
Better together: binary stars as probes of stellar evolution and fundamental physics
Kareem Al-Badry (Berkeley,MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract


Binary stars are foundational to modern astrophysics. They underpin precision measurements of stellar structure, age, and composition\; they provide the most stringent tests of general relativity, they make possible the study of faint and rare objects such as black holes and neutron stars, and they are the progenitors of gravitational wave sources. The components of binaries often interact, dramatically changing their evolution and giving rise to a spectacular zoo of astrophysical phenomenology. To understand stars -- particularly massive stars -- it is necessary to understand binaries. Large-scale stellar surveys such as Gaia, TESS, and SDSS-V are transforming the binary field, making possible both comprehensive population demographics and the discovery of rare objects. I will discuss new insights gleaned from surveys in recent years, including the creation of stripped-envelope stars following binary mass transfer, the formation of equal-mass "twin" binaries in circumbinary disks, the metallicity-dependence of the binary fraction, and the discovery of planets in binaries. I will focus in particular on the search for dormant stellar-mass black holes in binaries, discussing recent candidates and the path forward to characterizing the detached black hole population.

2021-05-28
15:00
Better together: binary stars as probes of stellar evolution and fundamental physics
Kareem Al-Badry (Berkeley,MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract


Binary stars are foundational to modern astrophysics. They underpin precision measurements of stellar structure, age, and composition\; they provide the most stringent tests of general relativity, they make possible the study of faint and rare objects such as black holes and neutron stars, and they are the progenitors of gravitational wave sources. The components of binaries often interact, dramatically changing their evolution and giving rise to a spectacular zoo of astrophysical phenomenology. To understand stars -- particularly massive stars -- it is necessary to understand binaries. Large-scale stellar surveys such as Gaia, TESS, and SDSS-V are transforming the binary field, making possible both comprehensive population demographics and the discovery of rare objects. I will discuss new insights gleaned from surveys in recent years, including the creation of stripped-envelope stars following binary mass transfer, the formation of equal-mass "twin" binaries in circumbinary disks, the metallicity-dependence of the binary fraction, and the discovery of planets in binaries. I will focus in particular on the search for dormant stellar-mass black holes in binaries, discussing recent candidates and the path forward to characterizing the detached black hole population.

2021-05-21
15:00
Studying quasar microlensing with robotic telescopes
Robert Schmidt (ZAH/ARI)
Königstuhl Kolloquium
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Abstract
Gravitationally lensed quasars are illusions where a background quasar is observed several times due to the light deflection by a foreground galaxy. Microlensing along the individual light paths causes variability of the quasar images, which lets us draw conclusions on the microlensing objects and the quasar engine. I sum up the state of the art and describe our monitoring program which uses the LCO robotic telescopes.

2021-05-21
15:00
Studying quasar microlensing with robotic telescopes
Robert Schmidt (ZAH/ARI)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Gravitationally lensed quasars are illusions where a background quasar is observed several times due to the light deflection by a foreground galaxy. Microlensing along the individual light paths causes variability of the quasar images, which lets us draw conclusions on the microlensing objects and the quasar engine. I sum up the state of the art and describe our monitoring program which uses the LCO robotic telescopes.

2021-05-21
15:00
Studying quasar microlensing with robotic telescopes
Robert Schmidt (ZAH/ARI)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Gravitationally lensed quasars are illusions where a background quasar is observed several times due to the light deflection by a foreground galaxy. Microlensing along the individual light paths causes variability of the quasar images, which lets us draw conclusions on the microlensing objects and the quasar engine. I sum up the state of the art and describe our monitoring program which uses the LCO robotic telescopes.

2021-05-21
15:00
Studying quasar microlensing with robotic telescopes
Robert Schmidt (ZAH/ARI)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
Gravitationally lensed quasars are illusions where a background quasar is observed several times due to the light deflection by a foreground galaxy. Microlensing along the individual light paths causes variability of the quasar images, which lets us draw conclusions on the microlensing objects and the quasar engine. I sum up the state of the art and describe our monitoring program which uses the LCO robotic telescopes.

2021-05-14
15:00
Knitting Together a New 3D View of our Milky Way Galaxy
Catherine Zucker (CfA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Until recently, much of our understanding of the 3D structure of our Milky Way was based on 2D observations of stars and dust, or spectral-line observations of gas. Distance measurements needed to turn the 2D sky into a 3D physical picture of the stars and interstellar clouds that form them were few and far between. In this talk, I will discuss how the rise of Gaia and large photometric surveys ? in combination with new data science and visualization techniques ? is quickly changing the landscape. In particular, I will show how 3D dust maps have received a huge distance resolution boost from Gaia and how 3D dust can be ?knitted? together with velocity information from gas and young stars to render new 3D spatial-kinematic views of our solar neighborhood. On small scales, I will present a new analysis of the 3D spatial topologies of local molecular clouds, linking the formation of a subset of these clouds to the expansion of a previously undiscovered feedback-driven superbubble. And on large scales, I will show how many of these clouds are connected into a 2.7-kpc-long undulating gaseous structure called the Radcliffe Wave, which redefines our understanding of the Local Arm nearby.

2021-05-14
15:00
Knitting Together a New 3D View of our Milky Way Galaxy
Catherine Zucker (CfA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Until recently, much of our understanding of the 3D structure of our Milky Way was based on 2D observations of stars and dust, or spectral-line observations of gas. Distance measurements needed to turn the 2D sky into a 3D physical picture of the stars and interstellar clouds that form them were few and far between. In this talk, I will discuss how the rise of Gaia and large photometric surveys ? in combination with new data science and visualization techniques ? is quickly changing the landscape. In particular, I will show how 3D dust maps have received a huge distance resolution boost from Gaia and how 3D dust can be ?knitted? together with velocity information from gas and young stars to render new 3D spatial-kinematic views of our solar neighborhood. On small scales, I will present a new analysis of the 3D spatial topologies of local molecular clouds, linking the formation of a subset of these clouds to the expansion of a previously undiscovered feedback-driven superbubble. And on large scales, I will show how many of these clouds are connected into a 2.7-kpc-long undulating gaseous structure called the Radcliffe Wave, which redefines our understanding of the Local Arm nearby.

2021-05-14
15:00
Knitting Together a New 3D View of our Milky Way Galaxy
Catherine Zucker (CfA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Until recently, much of our understanding of the 3D structure of our Milky Way was based on 2D observations of stars and dust, or spectral-line observations of gas. Distance measurements needed to turn the 2D sky into a 3D physical picture of the stars and interstellar clouds that form them were few and far between. In this talk, I will discuss how the rise of Gaia and large photometric surveys ? in combination with new data science and visualization techniques ? is quickly changing the landscape. In particular, I will show how 3D dust maps have received a huge distance resolution boost from Gaia and how 3D dust can be ?knitted? together with velocity information from gas and young stars to render new 3D spatial-kinematic views of our solar neighborhood. On small scales, I will present a new analysis of the 3D spatial topologies of local molecular clouds, linking the formation of a subset of these clouds to the expansion of a previously undiscovered feedback-driven superbubble. And on large scales, I will show how many of these clouds are connected into a 2.7-kpc-long undulating gaseous structure called the Radcliffe Wave, which redefines our understanding of the Local Arm nearby.

2021-05-07
15:00
Explaining the high accretion rates in transition disks
Matias Garate (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The origin of transition disks remains an unsolved puzzle in the process of planet formation, and this is mainly because of their seemingly contradictory properties. After all, how can we explain a population of disks that present large gaps that extend for tens of AUs, high accretion rates that are inconsistent with the inner disk lifetime, and bright luminosities that reveal a high content of millimeter sized grains, all at the same time? In this talk I will present our latest model of disk evolution, which includes both the effects of photoevaporative dispersal to explain the large gaps, and dead zones in the inner regions to explain the high accretion rates, and show that when these ingredients work together they can effectively reproduce the observed population of transition disk as a whole, covering the weak points that each models would have individually.

2021-05-07
15:00
Explaining the high accretion rates in transition disks
Matias Garate (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The origin of transition disks remains an unsolved puzzle in the process of planet formation, and this is mainly because of their seemingly contradictory properties. After all, how can we explain a population of disks that present large gaps that extend for tens of AUs, high accretion rates that are inconsistent with the inner disk lifetime, and bright luminosities that reveal a high content of millimeter sized grains, all at the same time? In this talk I will present our latest model of disk evolution, which includes both the effects of photoevaporative dispersal to explain the large gaps, and dead zones in the inner regions to explain the high accretion rates, and show that when these ingredients work together they can effectively reproduce the observed population of transition disk as a whole, covering the weak points that each models would have individually.

2021-05-07
15:00
Explaining the high accretion rates in transition disks
Matias Garate (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The origin of transition disks remains an unsolved puzzle in the process of planet formation, and this is mainly because of their seemingly contradictory properties. After all, how can we explain a population of disks that present large gaps that extend for tens of AUs, high accretion rates that are inconsistent with the inner disk lifetime, and bright luminosities that reveal a high content of millimeter sized grains, all at the same time? In this talk I will present our latest model of disk evolution, which includes both the effects of photoevaporative dispersal to explain the large gaps, and dead zones in the inner regions to explain the high accretion rates, and show that when these ingredients work together they can effectively reproduce the observed population of transition disk as a whole, covering the weak points that each models would have individually.

2021-04-30
15:00
PHANGS-ALMA : Our First Cloud-Scale Survey of Molecular Gas
Adam Leroy (OSU)
Königstuhl Kolloquium
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Abstract

I will present "PHANGS-ALMA" a multi-cycle ALMA survey of 90 nearby galaxies built around an ALMA Large Program. Leveraging ALMA's amazing combination of resolution, sensitivity, and mapping speed, PHANGS-ALMA mapped the CO 2-1 emission, our basic tracer of molecular gas in galaxies, at 1" = 50-150 pc resolution scales across essentially all accessible very nearby star-forming galaxies. This resolution represents a major leap forward because, for the first time, PHANGS-ALMA resolves the molecular gas across whole galaxies into individual star-forming molecular clouds, giving access to the demographics, life cycle, and properties of tens of thousands of molecular clouds across a representative set of z=0 galaxies. I will give an overview of the motivation and execution of the survey and then highlight results on each of these key topics - demographics, life cycles, and star formation properties of clouds - from the PHANGS team.

2021-04-30
15:00
PHANGS-ALMA : Our First Cloud-Scale Survey of Molecular Gas
Adam Leroy (OSU)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract

I will present "PHANGS-ALMA" a multi-cycle ALMA survey of 90 nearby galaxies built around an ALMA Large Program. Leveraging ALMA's amazing combination of resolution, sensitivity, and mapping speed, PHANGS-ALMA mapped the CO 2-1 emission, our basic tracer of molecular gas in galaxies, at 1" = 50-150 pc resolution scales across essentially all accessible very nearby star-forming galaxies. This resolution represents a major leap forward because, for the first time, PHANGS-ALMA resolves the molecular gas across whole galaxies into individual star-forming molecular clouds, giving access to the demographics, life cycle, and properties of tens of thousands of molecular clouds across a representative set of z=0 galaxies. I will give an overview of the motivation and execution of the survey and then highlight results on each of these key topics - demographics, life cycles, and star formation properties of clouds - from the PHANGS team.

2021-04-30
15:00
PHANGS-ALMA : Our First Cloud-Scale Survey of Molecular Gas
Adam Leroy (OSU)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract

I will present "PHANGS-ALMA" a multi-cycle ALMA survey of 90 nearby galaxies built around an ALMA Large Program. Leveraging ALMA's amazing combination of resolution, sensitivity, and mapping speed, PHANGS-ALMA mapped the CO 2-1 emission, our basic tracer of molecular gas in galaxies, at 1" = 50-150 pc resolution scales across essentially all accessible very nearby star-forming galaxies. This resolution represents a major leap forward because, for the first time, PHANGS-ALMA resolves the molecular gas across whole galaxies into individual star-forming molecular clouds, giving access to the demographics, life cycle, and properties of tens of thousands of molecular clouds across a representative set of z=0 galaxies. I will give an overview of the motivation and execution of the survey and then highlight results on each of these key topics - demographics, life cycles, and star formation properties of clouds - from the PHANGS team.

2021-04-23
15:00
Finding the sources of reionisation
Romain Meyer (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The epoch of (hydrogen) reionisation, during which hydrogen in the intergalactic medium was reionised by the first galaxies, was the last global phase transition of the Universe and ended about a billion years after the Big Bang. The last two decades have seen enormous progress in our understanding of cosmic reionisation. Whilst the timing and topology of reionisation are being constrained ever more precisely, the sources emitting the necessary ionising photons have however remained elusive. In this talk, I will discuss new measurements of the ionising output of high-redshift galaxies aiming to uncover which galaxies are responsible for reionisation and what this might imply for galaxy evolution.

2021-04-23
15:00
Finding the sources of reionisation
Romain Meyer (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The epoch of (hydrogen) reionisation, during which hydrogen in the intergalactic medium was reionised by the first galaxies, was the last global phase transition of the Universe and ended about a billion years after the Big Bang. The last two decades have seen enormous progress in our understanding of cosmic reionisation. Whilst the timing and topology of reionisation are being constrained ever more precisely, the sources emitting the necessary ionising photons have however remained elusive. In this talk, I will discuss new measurements of the ionising output of high-redshift galaxies aiming to uncover which galaxies are responsible for reionisation and what this might imply for galaxy evolution.

2021-04-23
15:00
Finding the sources of reionisation
Romain Meyer (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The epoch of (hydrogen) reionisation, during which hydrogen in the intergalactic medium was reionised by the first galaxies, was the last global phase transition of the Universe and ended about a billion years after the Big Bang. The last two decades have seen enormous progress in our understanding of cosmic reionisation. Whilst the timing and topology of reionisation are being constrained ever more precisely, the sources emitting the necessary ionising photons have however remained elusive. In this talk, I will discuss new measurements of the ionising output of high-redshift galaxies aiming to uncover which galaxies are responsible for reionisation and what this might imply for galaxy evolution.

2021-04-16
15:00
Mapping the assembly of discs via their chemical abundances
Francesco Belfiori (INAF-Arcetri)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The last five years have seen enormous progress in mapping local galaxies with integral field spectroscopy. Large surveys, like CALIFA, SAMI and MaNGA, have now provided us with a detailed view of star formation and chemical enrichment across the Hubble sequence at z=0. In this talk I will review what these observations have taught us about the chemo-dynamics of local disc galaxies, focusing on metallicity gradients as probes for disc assembly.

Moving beyond metallicity gradients requires mapping of ISM at the ?cloud-scale?, enabling us to resolve individual HII regions from the diffuse ionised gas background. I will present early results from the PHANGS-MUSE survey, a large program with the MUSE integral field spectrograph, which has recently obtained the first systematic view of the ionised ISM at the cloud scale (<\;50 pc) across a variety of local environments in a sample of 19 nearby galaxies. This dataset is allowing us to take the first step towards drawing a complete picture of the baryon cycle, and bridging the gap between the Milky Way and the extragalactic view of star formation and chemical enrichment.

2021-04-16
15:00
Mapping the assembly of discs via their chemical abundances
Francesco Belfiori (INAF-Arcetri)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The last five years have seen enormous progress in mapping local galaxies with integral field spectroscopy. Large surveys, like CALIFA, SAMI and MaNGA, have now provided us with a detailed view of star formation and chemical enrichment across the Hubble sequence at z=0. In this talk I will review what these observations have taught us about the chemo-dynamics of local disc galaxies, focusing on metallicity gradients as probes for disc assembly.

Moving beyond metallicity gradients requires mapping of ISM at the ?cloud-scale?, enabling us to resolve individual HII regions from the diffuse ionised gas background. I will present early results from the PHANGS-MUSE survey, a large program with the MUSE integral field spectrograph, which has recently obtained the first systematic view of the ionised ISM at the cloud scale (<\;50 pc) across a variety of local environments in a sample of 19 nearby galaxies. This dataset is allowing us to take the first step towards drawing a complete picture of the baryon cycle, and bridging the gap between the Milky Way and the extragalactic view of star formation and chemical enrichment.

2021-04-16
15:00
Mapping the assembly of discs via their chemical abundances
Francesco Belfiori (INAF-Arcetri)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The last five years have seen enormous progress in mapping local galaxies with integral field spectroscopy. Large surveys, like CALIFA, SAMI and MaNGA, have now provided us with a detailed view of star formation and chemical enrichment across the Hubble sequence at z=0. In this talk I will review what these observations have taught us about the chemo-dynamics of local disc galaxies, focusing on metallicity gradients as probes for disc assembly.

Moving beyond metallicity gradients requires mapping of ISM at the ?cloud-scale?, enabling us to resolve individual HII regions from the diffuse ionised gas background. I will present early results from the PHANGS-MUSE survey, a large program with the MUSE integral field spectrograph, which has recently obtained the first systematic view of the ionised ISM at the cloud scale (<\;50 pc) across a variety of local environments in a sample of 19 nearby galaxies. This dataset is allowing us to take the first step towards drawing a complete picture of the baryon cycle, and bridging the gap between the Milky Way and the extragalactic view of star formation and chemical enrichment.

2021-03-26
15:00
The Galactic centre told by its stellar population
Francisco Nogueras Lara (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The Galactic centre (GC) is the only galactic nucleus where we can resolve individual stars down to mili-parsec scales. Therefore, it constitutes a unique laboratory to study stellar nuclei and their role in the context of galaxy evolution. However, the high extinction and the extreme source crowding hamper the analysis of its stellar population and structure. In this talk, I will present the GALACTICNUCLEUS catalogue, a high angular resolution (~0.2'') photometric survey in the near infrared bands JHKs, that was specially designed to observe the GC. I will summarise our main results on the extinction analysis in the near infrared, the star formation history, and the distance to dark clouds in the central molecular zone.

2021-03-26
15:00
The Galactic centre told by its stellar population
Francisco Nogueras Lara (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The Galactic centre (GC) is the only galactic nucleus where we can resolve individual stars down to mili-parsec scales. Therefore, it constitutes a unique laboratory to study stellar nuclei and their role in the context of galaxy evolution. However, the high extinction and the extreme source crowding hamper the analysis of its stellar population and structure. In this talk, I will present the GALACTICNUCLEUS catalogue, a high angular resolution (~0.2'') photometric survey in the near infrared bands JHKs, that was specially designed to observe the GC. I will summarise our main results on the extinction analysis in the near infrared, the star formation history, and the distance to dark clouds in the central molecular zone.

2021-03-26
15:00
The Galactic centre told by its stellar population
Francisco Nogueras Lara (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
The Galactic centre (GC) is the only galactic nucleus where we can resolve individual stars down to mili-parsec scales. Therefore, it constitutes a unique laboratory to study stellar nuclei and their role in the context of galaxy evolution. However, the high extinction and the extreme source crowding hamper the analysis of its stellar population and structure. In this talk, I will present the GALACTICNUCLEUS catalogue, a high angular resolution (~0.2'') photometric survey in the near infrared bands JHKs, that was specially designed to observe the GC. I will summarise our main results on the extinction analysis in the near infrared, the star formation history, and the distance to dark clouds in the central molecular zone.

2021-03-19
15:00
The inner regions of protoplanetary disks: an interferometric view
Rebeca Garcia-Lopez (Uni. Dublin/MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
A first step towards understanding planetary formation is the characterisation of the structure and evolution of protoplanetary discs. Although the large scale disc is understood in some detail, very little is known about the inner few au. In this region, dust grains sublimate, and accretion and ejection take place, affecting the entire disk structure and evolution.

In this talk, I will review the most recent findings on the structure of the innermost regions of protoplanetary disks. In particular, I will focus on the main characteristics of this inner region as probed through VLTI-GRAVITY observations of dust and gas tracers, such as the CO and HI Br gamma emission. Finally, I will show what is our progress on image reconstruction of the inner disk.

2021-03-19
15:00
The inner regions of protoplanetary disks: an interferometric view
Rebeca Garcia-Lopez (Uni. Dublin/MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
A first step towards understanding planetary formation is the characterisation of the structure and evolution of protoplanetary discs. Although the large scale disc is understood in some detail, very little is known about the inner few au. In this region, dust grains sublimate, and accretion and ejection take place, affecting the entire disk structure and evolution.

In this talk, I will review the most recent findings on the structure of the innermost regions of protoplanetary disks. In particular, I will focus on the main characteristics of this inner region as probed through VLTI-GRAVITY observations of dust and gas tracers, such as the CO and HI Br gamma emission. Finally, I will show what is our progress on image reconstruction of the inner disk.

2021-03-19
15:00
The inner regions of protoplanetary disks: an interferometric view
Rebeca Garcia-Lopez (Uni. Dublin/MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
A first step towards understanding planetary formation is the characterisation of the structure and evolution of protoplanetary discs. Although the large scale disc is understood in some detail, very little is known about the inner few au. In this region, dust grains sublimate, and accretion and ejection take place, affecting the entire disk structure and evolution.

In this talk, I will review the most recent findings on the structure of the innermost regions of protoplanetary disks. In particular, I will focus on the main characteristics of this inner region as probed through VLTI-GRAVITY observations of dust and gas tracers, such as the CO and HI Br gamma emission. Finally, I will show what is our progress on image reconstruction of the inner disk.

2021-03-12
15:00
Exploring the metal-poor inner Milky Way with the Pristine survey
Anke Arentsen (Strasbourg)
Königstuhl Kolloquium
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Abstract
Exploring the metal-poor inner Milky Way with the Pristine survey

Anke Arentsen (Strasbourg)

Old, metal-poor stars can teach us about the First Stars and about the early formation and evolution of the Milky Way. A prediction of simulations is that the fraction of metal-poor stars that are very old is highest towards the centres of galaxies: in their bulges. However, searching for metal-poor stars in the bulge region of the Milky Way faces many challenges, so much is unknown about the properties of the metal-poor inner Galaxy. In this talk, I will introduce the Pristine Inner Galaxy Survey (PIGS) which has reached unprecedented efficiency in finding very metal-poor stars in the Galactic bulge region. I will present recent PIGS results on the chemistry (focusing on carbon-enhanced metal-poor stars) and the kinematics of the metal-poor inner Galaxy, and discuss what they can teach us about this ancient component of the Milky Way. \;

2021-03-12
15:00
Exploring the metal-poor inner Milky Way with the Pristine survey
Anke Arentsen (Strasbourg)
Königstuhl Kolloquium
Zoom,
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Abstract
Exploring the metal-poor inner Milky Way with the Pristine survey

Anke Arentsen (Strasbourg)

Old, metal-poor stars can teach us about the First Stars and about the early formation and evolution of the Milky Way. A prediction of simulations is that the fraction of metal-poor stars that are very old is highest towards the centres of galaxies: in their bulges. However, searching for metal-poor stars in the bulge region of the Milky Way faces many challenges, so much is unknown about the properties of the metal-poor inner Galaxy. In this talk, I will introduce the Pristine Inner Galaxy Survey (PIGS) which has reached unprecedented efficiency in finding very metal-poor stars in the Galactic bulge region. I will present recent PIGS results on the chemistry (focusing on carbon-enhanced metal-poor stars) and the kinematics of the metal-poor inner Galaxy, and discuss what they can teach us about this ancient component of the Milky Way. \;

2021-03-12
15:00
Exploring the metal-poor inner Milky Way with the Pristine survey
Anke Arentsen (Strasbourg)
Königstuhl Kolloquium
Zoom,
Show/hide abstract

Abstract
Exploring the metal-poor inner Milky Way with the Pristine survey

Anke Arentsen (Strasbourg)

Old, metal-poor stars can teach us about the First Stars and about the early formation and evolution of the Milky Way. A prediction of simulations is that the fraction of metal-poor stars that are very old is highest towards the centres of galaxies: in their bulges. However, searching for metal-poor stars in the bulge region of the Milky Way faces many challenges, so much is unknown about the properties of the metal-poor inner Galaxy. In this talk, I will introduce the Pristine Inner Galaxy Survey (PIGS) which has reached unprecedented efficiency in finding very metal-poor stars in the Galactic bulge region. I will present recent PIGS results on the chemistry (focusing on carbon-enhanced metal-poor stars) and the kinematics of the metal-poor inner Galaxy, and discuss what they can teach us about this ancient component of the Milky Way. \;

2021-03-05
15:00
from the instrument to the data analysis.
Faustine Cantalloube (MPIA) on High-contrast imaging of exoplanets and circumstellar disks
Königstuhl Kolloquium
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Abstract
High-contrast imaging of exoplanets and circumstellar disks: from the instrument to the data analysis.

Faustine Cantalloube (MPIA)

High-contrast imaging is one of the most challenging observational techniques in the visible infrared. It requires the best adaptive optics systems installed on the largest ground-based telescopes, advanced coronagraphs design, and dedicated image processing techniques. Thanks to the second generation of high-contrast instruments, such as VLT/SPHERE partially developed at MPIA, we now understand subtle effects stemming from the atmospheric turbulence and interacting all the way through the instrument, which drive the final performance of the instrument. This knowledge turns out to be of great interest in the context of the design of the future 40-m class telescopes instrument suite. In this talk, I will give an overview of exoplanet imaging from an instrumental perspective.

2021-03-05
15:00
from the instrument to the data analysis.
Faustine Cantalloube (MPIA) on High-contrast imaging of exoplanets and circumstellar disks
Königstuhl Kolloquium
Zoom,
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Abstract
High-contrast imaging of exoplanets and circumstellar disks: from the instrument to the data analysis.

Faustine Cantalloube (MPIA)

High-contrast imaging is one of the most challenging observational techniques in the visible infrared. It requires the best adaptive optics systems installed on the largest ground-based telescopes, advanced coronagraphs design, and dedicated image processing techniques. Thanks to the second generation of high-contrast instruments, such as VLT/SPHERE partially developed at MPIA, we now understand subtle effects stemming from the atmospheric turbulence and interacting all the way through the instrument, which drive the final performance of the instrument. This knowledge turns out to be of great interest in the context of the design of the future 40-m class telescopes instrument suite. In this talk, I will give an overview of exoplanet imaging from an instrumental perspective.

2021-03-05
15:00
from the instrument to the data analysis.
Faustine Cantalloube (MPIA) on High-contrast imaging of exoplanets and circumstellar disks
Königstuhl Kolloquium
Zoom,
Show/hide abstract

Abstract
High-contrast imaging of exoplanets and circumstellar disks: from the instrument to the data analysis.

Faustine Cantalloube (MPIA)

High-contrast imaging is one of the most challenging observational techniques in the visible infrared. It requires the best adaptive optics systems installed on the largest ground-based telescopes, advanced coronagraphs design, and dedicated image processing techniques. Thanks to the second generation of high-contrast instruments, such as VLT/SPHERE partially developed at MPIA, we now understand subtle effects stemming from the atmospheric turbulence and interacting all the way through the instrument, which drive the final performance of the instrument. This knowledge turns out to be of great interest in the context of the design of the future 40-m class telescopes instrument suite. In this talk, I will give an overview of exoplanet imaging from an instrumental perspective.

2021-02-19
15:00
Into the abyss - How the deep atmosphere influences observables in extrasolar planets
Ludmila Carone (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Exoplanet atmosphere studies are becoming more detailed with advances in models and observational facilities and methods. One particular aspect in exoplanet atmosphere science is becoming more and more important with more detailed data: the connection between the (3D) atmosphere of extrasolar planets and their interior.

Here, it is the optically thick atmosphere (1000 bar >\; p >\;1 bar) which provides a boundary layer between deeper processes and the observable atmosphere: Temperature and heat sources, composition, deep winds, magnetic field coupling ... all of these can shape the flow, temperature structure and chemistry in higher parts of the exoplanet atmospheres.

In this talk, I will given an overview of the so far recognized interior - exoplanet connections and how to diagnose these with current and upcoming facilities. I will show that ultra hot Jupiters and some key hot Jupiter planets will be particularly interesting to investigate for interior effects. And I will show that the atmosphere-interior connection becomes even more important and multi-faceted when going to smaller and smaller planets. Thus, understanding the influence of the interior in the currently most readily characterizable exoplanets is a pressing need.

2021-02-19
15:00
Into the abyss - How the deep atmosphere influences observables in extrasolar planets
Ludmila Carone (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Exoplanet atmosphere studies are becoming more detailed with advances in models and observational facilities and methods. One particular aspect in exoplanet atmosphere science is becoming more and more important with more detailed data: the connection between the (3D) atmosphere of extrasolar planets and their interior.

Here, it is the optically thick atmosphere (1000 bar >\; p >\;1 bar) which provides a boundary layer between deeper processes and the observable atmosphere: Temperature and heat sources, composition, deep winds, magnetic field coupling ... all of these can shape the flow, temperature structure and chemistry in higher parts of the exoplanet atmospheres.

In this talk, I will given an overview of the so far recognized interior - exoplanet connections and how to diagnose these with current and upcoming facilities. I will show that ultra hot Jupiters and some key hot Jupiter planets will be particularly interesting to investigate for interior effects. And I will show that the atmosphere-interior connection becomes even more important and multi-faceted when going to smaller and smaller planets. Thus, understanding the influence of the interior in the currently most readily characterizable exoplanets is a pressing need.

2021-02-19
15:00
Into the abyss - How the deep atmosphere influences observables in extrasolar planets
Ludmila Carone (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Exoplanet atmosphere studies are becoming more detailed with advances in models and observational facilities and methods. One particular aspect in exoplanet atmosphere science is becoming more and more important with more detailed data: the connection between the (3D) atmosphere of extrasolar planets and their interior.

Here, it is the optically thick atmosphere (1000 bar >\; p >\;1 bar) which provides a boundary layer between deeper processes and the observable atmosphere: Temperature and heat sources, composition, deep winds, magnetic field coupling ... all of these can shape the flow, temperature structure and chemistry in higher parts of the exoplanet atmospheres.

In this talk, I will given an overview of the so far recognized interior - exoplanet connections and how to diagnose these with current and upcoming facilities. I will show that ultra hot Jupiters and some key hot Jupiter planets will be particularly interesting to investigate for interior effects. And I will show that the atmosphere-interior connection becomes even more important and multi-faceted when going to smaller and smaller planets. Thus, understanding the influence of the interior in the currently most readily characterizable exoplanets is a pressing need.

2021-02-12
15:00
Observational signatures of AGN feedback across cosmic time
Dominika Wylezalek (ZAH/ARI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
AGN feedback is now widely considered to be one of the main drivers in regulating the growth of massive galaxies. In my talk I will describe several efforts to understand the power, reach and impact of AGN feedback processes. Using SDSS-IV MaNGA at low-z, we find significant evidence for AGN signatures even in low-luminosity AGN. Using molecular gas as a tracer, we are investigating if / how feedback may impact and quench galaxies at low-z. At higher redshift, we find that outflows can indeed suppress star formation in their hosts, consistent with the AGN having a 'negative' impact. However, both star formation and quasar activity peak at z ~ 2-3 where AGN are expected to impact the build-up of stellar mass the most. Our team recently discovered a unique population of luminous high-z quasars (ERQs) with extreme outflow properties. At the same time, more and more exotic AGN populations with extreme signatures are being discovered at that redshift. These populations are ideal to obtain a census of the overall mass and energy budget of both outflow and infall/feeding from the CGM, an essential requirement to probe the detailed and full feedback loop. I will present recent efforts in our group to characterise feedback processes in powerful AGN on CGM scales at and near cosmic noon.

Finally, I will also introduce the JWST ERS Program "Q3D" which will study the impact of three carefully selected luminous quasars on their hosts. Our program will serve as a pathfinder for JWST science investigations in IFU mode.

2021-02-12
15:00
TBA
Dominika Wylezalek (ZAH/ARI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2021-02-05
15:00
Gaia & the fingerprints of the Galactic bar ? a dynamical Milkay Way mystery
Wilma Trick (MPA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2021-02-05
15:00
Gaia & the fingerprints of the Galactic bar ? a dynamical Milky Way mystery
Wilma Trick (MPA)
Königstuhl Kolloquium
Zoom,
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Abstract

The Milky Way's disk around the Sun is interspersed by 7 streams of stars, amongst them the famous "Hercules", "Sirius", and "Hyades" moving groups. These streaming motions are caused by some powerful perturber. Suspects are the spiral arms, satellites, and/or the Galactic bar. So far, the true culprit has been notoriously elusive.

This talk shows how stars whose orbits are in resonance with the Galactic bar exhibit distinctive patterns in action-angle space. Based on these fingerprints, the exquisite Gaia data narrows down the search for the bar's Outer Lindblad Resonance (OLR) to two likely candidates: the "Hat" and the "Sirius" moving groups.

Finally pinning down the true OLR (and therefore the pattern speed of the Galactic bar) will be a milestone in uncovering the Milky Way's structure and evolution.


2021-01-29
15:00
TBA
Sarah Bosman (MPIA)
Königstuhl Kolloquium
zoom,
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Abstract
Beyond the Lyman-? forest: Understanding the end stages of Reionization

Hydrogen reionization is a crucial period during the Universe's history during which the first galaxies drive a global phase transition signaling the end of the Cosmic Dark Ages. Our observational view of reionization has changed drastically since Planck measurements pushed the timing of the process to later times, and in reach of direct observation through quasar spectroscopy. Ironically, the increase in observational data has raised more questions than it has answered. The timing of the end of reionization, as well as its morphology and the processes driving its end stages, are being hotly debated. I will review our current understanding of reionization's end stages, and present preliminary results from the XQR-30 collaboration: a 248-hour Large Program that is increasing the number of high-quality quasar spectroscopy during reionization four-fold. New developments are happening very quickly and offering the first solid insights into the properties of early galaxies driving reionization during the first billion years.

2021-01-29
15:00
TBA
Sarah Bosman (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2021-01-22
15:00
CARMENES, the exoplanet finder: Uncovering nearby exoplanet systems with precision radial velocity measurements
Trifon Trifonov (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
CARMENES is a high-resolution optical and near-infrared spectrograph(s) mounted at the 3.6m telescope in Calar Alto, Spain. The CARMENES exoplanet survey began in 2016, targeting over 350 nearby M-dwarf stars. Since then, CARMENES has proven to be one of the most effective Radial Velocity (RV) exoplanet finders currently in operation. I will briefly present the CARMENES-GTO Doppler survey, its scientific goals, and I will focus on some of the exciting CARMENES-GTO exoplanet discoveries. I will show that CARMENES is fully capable of discovering complex multiple-planet systems around late M-dwarf stars, which cannot be studied by other instruments. I will reveal the powerful synergy between CARMENES and the Transiting Exoplanet Survey Satellite (TESS), leading to a dozen exoplanet discoveries. One of the most exciting CARMENES discoveries, confirmed by TESS, is a nearby transiting rocky exoplanet that will be a prime target for atmospheric investigation and characterization with the JWST. The precise orbital determination based on CARMENES precision RVs is vital for probing the planetary formation mechanisms and evolution scenarios around low-mass stars and in general.

2021-01-22
15:00
TBA
Trifon Trifonov (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2021-01-15
15:00
Star formation and its quenching: insights from radio continuum and multiwavelength surveys
Sarah Leslie (Leiden)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract

There are two main populations of galaxies in the universe, those forming stars and those no longer forming stars (quiescent). Explaining the quiescent population requires poorly constrained mechanisms referred to as ''quenching'' to interrupt the star formation process. Radio source counts are dominated by AGN at high flux densities and star-forming galaxies at low flux densities. With contemporary interferometers like ASKAP, MeerKAT/MIGHTEE, and LOFAR, we are starting to survey wide areas at unprecedented depths, detecting millions of normal star-forming galaxies and low-luminosity AGN out to high redshift. In this talk, I will focus on (1) new results with LOFAR and VLA on calibrating the radio -- SFR relation and its application as a dust unbiased tracer of star formation, and (2) recent work using MaNGA and LOFAR to investigate AGN feedback in the local universe.



Frithjof Brauer Memorial Award talk

2021-01-15
15:00
Brauer Award talk
Sarah Leslie (Leiden)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2021-01-08
15:00
Connecting the dots: Numerical models of AGN and their particle acceleration
F. Spanier (ITA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Active Galactic Nuclei are an interesting source not only for photons in a very wide energy range, but also for cosmic rays and neutrinos. The emission of these different messengers is most likely connected to each other. To understand the physics behind AGN, emission models have to be constructed. Nowadays observational data is available from radio frequencies to TeV energies and neutrino observatories like IceCUBE may provide ultra-high energy neutrino counts. Unfortunately long-term simultaneous multi-wavelength observations are still scarce. I will present results from time-dependent and spatially resolved AGN emission models that allow for a self-consistent treatment of emission and particle acceleration within AGN. These models may help to distinguish different emission processes using the timing of lightcurves in separate energy bands. But they may also provide answers to questions like "What is the shape of an AGN jet?" or "Is there really one neutrino per one high-energy photon?"

2021-01-08
15:00
Connecting the dots: Numerical models of AGN and their particle acceleration
F. Spanier (ITA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Active Galactic Nuclei are an interesting source not only for photons in a very wide energy range, but also for cosmic rays and neutrinos. The emission of these different messengers is most likely connected to each other. To understand the physics behind AGN, emission models have to be constructed. Nowadays observational data is available from radio frequencies to TeV energies and neutrino observatories like IceCUBE may provide ultra-high energy neutrino counts. Unfortunately long-term simultaneous multi-wavelength observations are still scarce. I will present results from time-dependent and spatially resolved AGN emission models that allow for a self-consistent treatment of emission and particle acceleration within AGN. These models may help to distinguish different emission processes using the timing of lightcurves in separate energy bands. But they may also provide answers to questions like "What is the shape of an AGN jet?" or "Is there really one neutrino per one high-energy photon?"

2020-12-18
15:00
Big Steps Toward Small Words: Exoplanet Atmosphere Characterization of Sub-Neptunes and Super-Earths
Laura Kreidberg (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Planets in between the size of Earth and Neptune are one of the dominant outcomes of planet formation. These worlds have no analogue in the Solar System, and their existence gives rise to many questions: what is their typical bulk composition? how do they form? what are their climates like? To address these questions, we turn to atmosphere characterization, which can provide a wealth of additional information about the planets beyond their masses and radii. In this talk, I will share new results from Hubble and Spitzer observational campaigns focused on small planet atmospheres, including (1) a search for demographic trends in the cloud properties and composition of sub-Neptunes, and (2) searches for an atmosphere on two hot rocky super-Earths.

2020-12-18
15:00
Big Steps Toward Small Words: Exoplanet Atmosphere Characterization of Sub-Neptunes and Super-Earths
Laura Kreidberg (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Planets in between the size of Earth and Neptune are one of the dominant outcomes of planet formation. These worlds have no analogue in the Solar System, and their existence gives rise to many questions: what is their typical bulk composition? how do they form? what are their climates like? To address these questions, we turn to atmosphere characterization, which can provide a wealth of additional information about the planets beyond their masses and radii. In this talk, I will share new results from Hubble and Spitzer observational campaigns focused on small planet atmospheres, including (1) a search for demographic trends in the cloud properties and composition of sub-Neptunes, and (2) searches for an atmosphere on two hot rocky super-Earths.

2020-12-11
15:00
Stellar clustering connecting the formation and evolution of galaxies to the formation and evolution of us
Diederik Kruijssen (Heidelberg University)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The clustered nature of star formation leaves a long-term imprint on galaxies, stars, and planets. At young ages, stellar clustering subdivides galaxies into individual building blocks undergoing vigorous, feedback-driven life cycles that vary with the galactic environment. These units structure the interstellar medium spatially, dynamically and chemically, and collectively define how galaxies form stars. At old ages, the relics of clustered star formation persist as ancient globular clusters, which hold a wealth of information allowing us to reconstruct the assembly histories of galaxies, culminating in the reconstruction of the Milky Way's merger tree. Towards smaller scales, stellar clustering has a measurable impact on the evolution of protoplanetary discs, the architectures of planetary systems, and the properties of planets themselves. I will discuss how this web of physical processes across a hierarchy of scales defines the cosmic ecosystem that we live in, and demonstrate that stellar clustering is at its focal point.

2020-12-11
15:00
Stellar clustering connecting the formation and evolution of galaxies to the formation and evolution of us
Diederik Kruijssen (Heidelberg University)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The clustered nature of star formation leaves a long-term imprint on galaxies, stars, and planets. At young ages, stellar clustering subdivides galaxies into individual building blocks undergoing vigorous, feedback-driven life cycles that vary with the galactic environment. These units structure the interstellar medium spatially, dynamically and chemically, and collectively define how galaxies form stars. At old ages, the relics of clustered star formation persist as ancient globular clusters, which hold a wealth of information allowing us to reconstruct the assembly histories of galaxies, culminating in the reconstruction of the Milky Way's merger tree. Towards smaller scales, stellar clustering has a measurable impact on the evolution of protoplanetary discs, the architectures of planetary systems, and the properties of planets themselves. I will discuss how this web of physical processes across a hierarchy of scales defines the cosmic ecosystem that we live in, and demonstrate that stellar clustering is at its focal point.

2020-12-04
15:00
Star Formation in the Turbulent-Multiphase Interstellar Medium
Shmuel Bialy (CfA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract

I will start with a broad review of the field of star formation and galaxy evolution, and some pressing open questions. I will then dive into the star-forming interstellar medium (ISM), asking the question, what regulates the star formation process on galactic scales? I will discuss the multiphase structure of the ISM, heating-cooling processes, and turbulence, all of which may play an important \;role in regulating star formation.  \;I will focus on a particularly appealing theory in which far-UV radiation from massive stars introduces a natural \;self-regulation process for star-formation, and will present recent results \; (Bialy 2020) for the intimate link between star-formation rate and the far-UV radiation intensity in the ISM. I will conclude by discussing promising future directions: (1) charting new ways for constraining poorly known interstellar properties: turbulence, 3D ISM structure, the nature of low energy cosmic-rays, and (2) an ongoing effort to construct an improved star-formation model for next-generation cosmological simulations (i.e., IllustrisTNG successors).

2020-12-04
15:00
Star Formation in the Turbulent-Multiphase Interstellar Medium
Shmuel Bialy (CfA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract

I will start with a broad review of the field of star formation and galaxy evolution, and some pressing open questions. I will then dive into the star-forming interstellar medium (ISM), asking the question, what regulates the star formation process on galactic scales? I will discuss the multiphase structure of the ISM, heating-cooling processes, and turbulence, all of which may play an important \;role in regulating star formation.  \;I will focus on a particularly appealing theory in which far-UV radiation from massive stars introduces a natural \;self-regulation process for star-formation, and will present recent results \; (Bialy 2020) for the intimate link between star-formation rate and the far-UV radiation intensity in the ISM. I will conclude by discussing promising future directions: (1) charting new ways for constraining poorly known interstellar properties: turbulence, 3D ISM structure, the nature of low energy cosmic-rays, and (2) an ongoing effort to construct an improved star-formation model for next-generation cosmological simulations (i.e., IllustrisTNG successors).

2020-11-27
15:00
Neige Frankel, Nico Krieger, Alessandro Savino
Patzer Colloquium (MPIA/ZAH)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Celebration of the Awardees and short presentations by each of them.

2020-11-27
15:00
Neige Frankel, Nico Krieger, Alessandro Savino
Patzer Colloquium (MPIA/ZAH)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Celebration of the Awardees and short presentations by each of them.

2020-11-20
15:00
Everything Flows: The dynamics of the molecular interstellar medium
Jonathan Henshaw (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The density structure of the interstellar medium determines where stars form and release energy, momentum and heavy elements, driving galaxy evolution. Density variations are seeded and amplified by gas motion, but the exact nature of this motion is unknown across spatial scales and galactic environments. Although dense star-forming gas probably emerges from a combination of instabilities, convergent atomic/molecular flows and turbulence, establishing the precise origin is challenging because it requires gas motion to be quantified over many orders of magnitude in spatial scale. I will present our work in which we have measured the motion of molecular gas in the Milky Way and in nearby galaxy NGC 4321, thereby assembling observations that span an unprecedented spatial dynamic range 10-1 \;?103 \;pc. I will demonstrate how our analysis has allowed us to visualise the molecular interstellar medium in a new way, leading to the discovery of wave-like velocity fluctuations across all spatial scales and galactic environments. I will describe how the combined analysis of density and velocity fluctuations can help to establish the physical driving mechanisms of interstellar gas flows, and emphasise that structures within the interstellar medium cannot be considered in isolation. Instead, their formation and evolution are controlled by nested, interdependent flows of matter covering many orders of magnitude in spatial scale. \;

2020-11-20
15:00
Everything Flows: The dynamics of the molecular interstellar medium
Jonathan Henshaw (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The density structure of the interstellar medium determines where stars form and release energy, momentum and heavy elements, driving galaxy evolution. Density variations are seeded and amplified by gas motion, but the exact nature of this motion is unknown across spatial scales and galactic environments. Although dense star-forming gas probably emerges from a combination of instabilities, convergent atomic/molecular flows and turbulence, establishing the precise origin is challenging because it requires gas motion to be quantified over many orders of magnitude in spatial scale. I will present our work in which we have measured the motion of molecular gas in the Milky Way and in nearby galaxy NGC 4321, thereby assembling observations that span an unprecedented spatial dynamic range 10-1 \;?103 \;pc. I will demonstrate how our analysis has allowed us to visualise the molecular interstellar medium in a new way, leading to the discovery of wave-like velocity fluctuations across all spatial scales and galactic environments. I will describe how the combined analysis of density and velocity fluctuations can help to establish the physical driving mechanisms of interstellar gas flows, and emphasise that structures within the interstellar medium cannot be considered in isolation. Instead, their formation and evolution are controlled by nested, interdependent flows of matter covering many orders of magnitude in spatial scale. \;

2020-11-13
15:00
ASPECS - The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field (www.aspecs.info)
Fabian Walter (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract

I will report on some of the results emerging from the ALMA large program ASPECS (aspecs.info). ASPECS obtained deep imaging in the 1mm and 3mm bands of the Hubble Ultra-Deep Field (H-UDF) through frequency scans. The observations provide a full census of dust and molecular gas in the H-UDF, down to masses that are typical of main-sequence galaxies at redshifts 1-4. The resulting data products enable a great range of studies, from the characterisation of individual galaxies, capitalizing on the unique multi-wavelength dataset of the H-UDF, to CO excitation studies to constrain the gas properties of the distant galaxies. A 3D stacking analysis using precise redshifts from major VLT/MUSE initiatives on the field helped in recovering additional emission of galaxy samples that are too faint to be detected individually. Stacking in both the continuum and line (capitalizing on 100s of spectroscopic redshifts from major VLT/MUSE initiatives on the H-UDF) pushed the detection limits further. The nature of the observations (full spectral scans) provides a census of dust and molecular gas in the cosmic volume defined by the H-UDF. The resulting cosmic molecular gas density as a function of redshift shows an order of magnitude decrease from z=2 to z=0. This is markably different from independent measurements of the atomic gas phase that shows a rather flat redshift dependence. These measurements can be used to put new constraints on the gas accretion process that is needed to explain the build-up of stellar mass in galaxies through cosmic history.

2020-11-13
15:00
ASPECS - The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field (www.aspecs.info)
Fabian Walter (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract

I will report on some of the results emerging from the ALMA large program ASPECS (aspecs.info). ASPECS obtained deep imaging in the 1mm and 3mm bands of the Hubble Ultra-Deep Field (H-UDF) through frequency scans. The observations provide a full census of dust and molecular gas in the H-UDF, down to masses that are typical of main-sequence galaxies at redshifts 1-4. The resulting data products enable a great range of studies, from the characterisation of individual galaxies, capitalizing on the unique multi-wavelength dataset of the H-UDF, to CO excitation studies to constrain the gas properties of the distant galaxies. A 3D stacking analysis using precise redshifts from major VLT/MUSE initiatives on the field helped in recovering additional emission of galaxy samples that are too faint to be detected individually. Stacking in both the continuum and line (capitalizing on 100s of spectroscopic redshifts from major VLT/MUSE initiatives on the H-UDF) pushed the detection limits further. The nature of the observations (full spectral scans) provides a census of dust and molecular gas in the cosmic volume defined by the H-UDF. The resulting cosmic molecular gas density as a function of redshift shows an order of magnitude decrease from z=2 to z=0. This is markably different from independent measurements of the atomic gas phase that shows a rather flat redshift dependence. These measurements can be used to put new constraints on the gas accretion process that is needed to explain the build-up of stellar mass in galaxies through cosmic history.

2020-11-13
15:00
TBD
Maryam Modjaz (NYU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2020-11-06
15:00
Stellar Forensics with the Most Powerful Explosions in the Universe
Maryam Modjaz (NYU)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Core-collapse Supernovae (SNe), Long-duration Gamma-ray Bursts (GRBs) and exotic transients are exploding massive stars and constitute the most powerful explosions in the universe. Because they are visible over large cosmological distances, release elements heavier than Helium, and leave behind extreme remnants such as black holes, they are fascinating objects, as well as crucial tools for many areas of astrophysics.

However, for many decades the fundamental question of which stellar systems give rise to which kinds of explosions has remained outstanding. I will discuss the exciting recent progress that we have made on this question in key areas by publishing and thoroughly analyzing the largest data sets in the world at the time, as well as by developing sophisticated radiative transfer methods to reconstruct the exploded star. I will conclude with an outlook on how the most promising venues of research - using the existing and upcoming innovative large time-domain surveys such as Zwicky Transient Facility II and Rubin's LSST - will shed new light on the diverse deaths of stars.

2020-11-06
15:00
TBD
Maryam Modjaz (NYU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2020-11-06
15:00
Stellar Forensics with the Most Powerful Explosions in the Universe
Maryam Modjaz (NYU)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Core-collapse Supernovae (SNe), Long-duration Gamma-ray Bursts (GRBs) and exotic transients are exploding massive stars and constitute the most powerful explosions in the universe. Because they are visible over large cosmological distances, release elements heavier than Helium, and leave behind extreme remnants such as black holes, they are fascinating objects, as well as crucial tools for many areas of astrophysics.

However, for many decades the fundamental question of which stellar systems give rise to which kinds of explosions has remained outstanding. I will discuss the exciting recent progress that we have made on this question in key areas by publishing and thoroughly analyzing the largest data sets in the world at the time, as well as by developing sophisticated radiative transfer methods to reconstruct the exploded star. I will conclude with an outlook on how the most promising venues of research - using the existing and upcoming innovative large time-domain surveys such as Zwicky Transient Facility II and Rubin's LSST - will shed new light on the diverse deaths of stars.

2020-10-30
15:00
Astronomy And Space Science: On Top Of Children'S Interest
Anders Jidesjö & Svein Sjøberg (University of Oslo, Linköping University)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Experts in science education Anders Jidesjö (Linköping University) and Svein Sjoberg (University of Oslo) will talk about
"Astronomy And Space Science: On Top Of Children's Interest"

The two talks present the ROSE-project (Relevance Of Science Education), a study of how 15 year old students in different countries relate to science and technology. Svein Sjoborg will present the background and development of ROSE, a study for which young people from some 50 countries expressed their experiences, attitudes, interests and future plans. Data reveal interesting differences between young people from different countries as well as large differences between girls and boys. Astronomy comes out in a most positive way. Anders Jidesjö will present the set-up and first results of the second phase ROSE Second (ROSES).
Key results will be presented and some impacts for science and science education will be discussed.

2020-10-30
15:00
Astronomy And Space Science: On Top Of Children'S Interest
Anders Jidesjö & Svein Sjøberg (University of Oslo, Linköping University)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
Experts in science education Anders Jidesjö (Linköping University) and Svein Sjoberg (University of Oslo) will talk about
"Astronomy And Space Science: On Top Of Children's Interest"

The two talks present the ROSE-project (Relevance Of Science Education), a study of how 15 year old students in different countries relate to science and technology. Svein Sjoborg will present the background and development of ROSE, a study for which young people from some 50 countries expressed their experiences, attitudes, interests and future plans. Data reveal interesting differences between young people from different countries as well as large differences between girls and boys. Astronomy comes out in a most positive way. Anders Jidesjö will present the set-up and first results of the second phase ROSE Second (ROSES).
Key results will be presented and some impacts for science and science education will be discussed.

2020-10-23
15:00
The cycle of matter in the magnetized interstellar medium as revealed by machine vision
Juan Soler (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Machine vision is the general name given to the methods for automatic inspection and analysis of images, from pattern recognition to object classification. I will present the results of machine vision techniques applied to the study of the formation and evolution of star-forming clouds in the Milky Way, both in observations and numerical simulations. First, the characterization of filamentary structures in the observations of the atomic hydrogen (HI) emission at 21 cm in The HI/OH/Recombination-line (THOR) survey of the Galactic plane. Second, the evaluation of the correlation between the HI emission and the emission from molecular species in star-forming clouds. Finally, in the study of the anisotropy introduced by the interstellar magnetic fields in the velocity field in and around star-forming clouds.

2020-10-23
15:00
The cycle of matter in the magnetized interstellar medium as revealed by machine vision
Juan Soler (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Machine vision is the general name given to the methods for automatic inspection and analysis of images, from pattern recognition to object classification. I will present the results of machine vision techniques applied to the study of the formation and evolution of star-forming clouds in the Milky Way, both in observations and numerical simulations. First, the characterization of filamentary structures in the observations of the atomic hydrogen (HI) emission at 21 cm in The HI/OH/Recombination-line (THOR) survey of the Galactic plane. Second, the evaluation of the correlation between the HI emission and the emission from molecular species in star-forming clouds. Finally, in the study of the anisotropy introduced by the interstellar magnetic fields in the velocity field in and around star-forming clouds.

2020-10-16
15:00
Constraining the Reionization History with the Most Distant Quasars
Fred Davies (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
The epoch of reionization was a pivotal moment in the history of the Universe when the cumulative output of ionizing UV photons from the first stars, galaxies, and accreting black holes surpassed the total number of hydrogen atoms in the intergalactic medium. Key uncertainties remain in the nature of both the sources and sinks of ionizing photons, but the time evolution of the intergalactic neutral hydrogen fraction provides a joint constraint on the formation of these early cosmic structures. I will summarize the crucial role that observations of the most distant, luminous quasars have played in constraining the neutral fraction during the epoch of reionization, both from a (recent) historical perspective and via new measurements of hydrogen Lyman-alpha damping wing absorption in newly-discovered quasars at redshifts above 7. I will also highlight several other promising avenues for constraining the reionization history, which will become even more powerful in the era of Euclid and JWST.

2020-10-16
15:00
Constraining the Reionization History with the Most Distant Quasars
Fred Davies (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
The epoch of reionization was a pivotal moment in the history of the Universe when the cumulative output of ionizing UV photons from the first stars, galaxies, and accreting black holes surpassed the total number of hydrogen atoms in the intergalactic medium. Key uncertainties remain in the nature of both the sources and sinks of ionizing photons, but the time evolution of the intergalactic neutral hydrogen fraction provides a joint constraint on the formation of these early cosmic structures. I will summarize the crucial role that observations of the most distant, luminous quasars have played in constraining the neutral fraction during the epoch of reionization, both from a (recent) historical perspective and via new measurements of hydrogen Lyman-alpha damping wing absorption in newly-discovered quasars at redshifts above 7. I will also highlight several other promising avenues for constraining the reionization history, which will become even more powerful in the era of Euclid and JWST.

2020-10-09
15:00
Sgr A* - measuring the super massive black hole in the center of the Milky Way
Wolfgang Brandner (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Invisible in the optical, a super massive black hole rules the center of the Milky Way. For its proof-of-existence and its study, Andrea Ghez (UCLA) and Reinhard Genzel (MPE) were awarded the Nobel prize in Physics 2020. I will briefly summarise the science highlights. MPIA contributed significantly to these discoveries with the near infrared camera CONICA, which was part of the adaptive optics system NACO at the ESO VLT, and the Coudé Infrared Adaptive Optics (CIAO) systems, which are part of the GRAVITY VLTI instrument. The main focus of the observations were the measurements of stellar orbits and the investigation of brightness outbursts in the immediate vicinity of the black hole, and a comparison with the predictions of Einstein's special and general theory of relativity.

2020-10-09
15:00
Sgr A* - measuring the super massive black hole in the center of the Milky Way
Wolfgang Brandner (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Invisible in the optical, a super massive black hole rules the center of the Milky Way. For its proof-of-existence and its study, Andrea Ghez (UCLA) and Reinhard Genzel (MPE) were awarded the Nobel prize in Physics 2020. I will briefly summarise the science highlights. MPIA contributed significantly to these discoveries with the near infrared camera CONICA, which was part of the adaptive optics system NACO at the ESO VLT, and the Coudé Infrared Adaptive Optics (CIAO) systems, which are part of the GRAVITY VLTI instrument. The main focus of the observations were the measurements of stellar orbits and the investigation of brightness outbursts in the immediate vicinity of the black hole, and a comparison with the predictions of Einstein's special and general theory of relativity.

2020-10-02
15:00
Zooming in on star and disk formation
Asmita Bhandare (MPIA/CRAL)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Magnetized, cold, dense molecular cloud cores provide the birth environment for stars and disks. The multi-scale scenario of low-mass star formation occurs via the formation of two quasi-hydrostatic cores. In this talk I will discuss results from numerical simulations used to probe the gravitational collapse process that involves the transition of an isolated molecular cloud core to a hydrostatic core with a surrounding disk. We use the PLUTO code to perform radiation (magneto-)hydrodynamic simulations using one- and two-dimensional (2D) grids. Additionally, we use for the gas equation of state density- and temperature-dependent thermodynamic quantities to account for dissociation, ionization, and molecular vibrations and rotations. Using spherically symmetric simulations we survey a wide range of initial low- to high-mass (0.5 - 100 Msun) molecular cloud cores, yielding the largest parameter scan so far. The results highlight that in the high-mass regime first hydrostatic cores do not have time to evolve because of the large accretion rates. We perform 2D collapse simulations with an unprecedented resolution to model the evolution of the second hydrostatic core. For the first time, these studies demonstrate the onset of convection within the second core for the collapse cases of non-rotating molecular cloud cores in the low-mass regime. This supports the interesting possibility that dynamo-driven magnetic fields may be generated during the very early phases of low-mass star formation. Furthermore, I will discuss the impact of different cloud properties on the formation of protostellar disks and the launching of magnetically driven outflows during the early stages of star formation. These models will serve as the foundation for follow-up studies that link theoretical insights with observational signatures.

2020-10-02
15:00
Zooming in on star and disk formation
Asmita Bhandare (MPIA/CRAL)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
Show/hide abstract

Abstract
Magnetized, cold, dense molecular cloud cores provide the birth environment for stars and disks. The multi-scale scenario of low-mass star formation occurs via the formation of two quasi-hydrostatic cores. In this talk I will discuss results from numerical simulations used to probe the gravitational collapse process that involves the transition of an isolated molecular cloud core to a hydrostatic core with a surrounding disk. We use the PLUTO code to perform radiation (magneto-)hydrodynamic simulations using one- and two-dimensional (2D) grids. Additionally, we use for the gas equation of state density- and temperature-dependent thermodynamic quantities to account for dissociation, ionization, and molecular vibrations and rotations. Using spherically symmetric simulations we survey a wide range of initial low- to high-mass (0.5 - 100 Msun) molecular cloud cores, yielding the largest parameter scan so far. The results highlight that in the high-mass regime first hydrostatic cores do not have time to evolve because of the large accretion rates. We perform 2D collapse simulations with an unprecedented resolution to model the evolution of the second hydrostatic core. For the first time, these studies demonstrate the onset of convection within the second core for the collapse cases of non-rotating molecular cloud cores in the low-mass regime. This supports the interesting possibility that dynamo-driven magnetic fields may be generated during the very early phases of low-mass star formation. Furthermore, I will discuss the impact of different cloud properties on the formation of protostellar disks and the launching of magnetically driven outflows during the early stages of star formation. These models will serve as the foundation for follow-up studies that link theoretical insights with observational signatures.

2020-09-25
15:00
Probing dark matter models with dynamical and assembly histories of galaxies
Ryan Leaman (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Small scale cold dark matter (CDM) problems have been reconciled with observations by considering the effect of stellar feedback on low mass galaxies. However viable alternative particle physics models for dark matter also alleviate these cusp-core and missing satellite problems. The next challenge in near-field cosmology is to develop techniques which separate the degenerate classes of solutions
(CDM+feedback vs. non-standard DM models) to small-scale structure problems in the Universe. I will discuss two complementary methods to address this: 1) composite gas and stellar kinematic observations of nearby galaxies to provide constraints on DM particle properties, and 2) a new method to recover galaxy accretion histories as a way to probe abundances of low mass subhalos. Together with existing direct detection experiments, these astrophysical tests provide an important way forward in studying a fundamental question in cosmology - what is dark matter?

2020-09-25
15:00
Probing dark matter models with dynamical and assembly histories of galaxies
Ryan Leaman (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Small scale cold dark matter (CDM) problems have been reconciled with observations by considering the effect of stellar feedback on low mass galaxies. However viable alternative particle physics models for dark matter also alleviate these cusp-core and missing satellite problems. The next challenge in near-field cosmology is to develop techniques which separate the degenerate classes of solutions
(CDM+feedback vs. non-standard DM models) to small-scale structure problems in the Universe. I will discuss two complementary methods to address this: 1) composite gas and stellar kinematic observations of nearby galaxies to provide constraints on DM particle properties, and 2) a new method to recover galaxy accretion histories as a way to probe abundances of low mass subhalos. Together with existing direct detection experiments, these astrophysical tests provide an important way forward in studying a fundamental question in cosmology - what is dark matter?

2020-09-11
15:00
TBD
Arianna Musso Barcucci (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2020-09-04
15:00
TBD
Sascha Quanz (ETH)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2020-08-28
15:00
TBD
Asmita Bhandare (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2020-08-07
15:00
Near-field cosmology with the rapid neutron-capture process
Alexander Ji (Carnegie)
Königstuhl Kolloquium
via zoom,
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Abstract
In the first billion years of the universe, stars and galaxies formed in the smallest dark matter halos, produced high-energy photons that reionized the intergalactic medium, and polluted the universe with the first heavy elements. Near-field cosmology probes this early era by observing nearby relic galaxies that have survived from ancient times. In particular, the elemental abundances of their old, metal-poor stars encode otherwise inaccessible information about the first stellar populations and first galaxy formation histories. Decoding these abundances requires connecting nuclear and stellar astrophysics to galaxy formation and hierarchical assembly. I will show how stellar abundances of metal-poor stars have shaped our current understanding of the rapid neutron-capture process (r-process), including how they inform future multi-messenger observations of kilonovae. The r-process can in turn be used to build our understanding of the high-redshift universe, including galaxy formation in the faintest dwarf galaxies and the hierarchical assembly of our Milky Way's stellar halo.

2020-08-07
15:00
Near-field cosmology with the rapid neutron-capture process
Alexander Ji (Carnegie)
Königstuhl Kolloquium
via zoom,
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Abstract
In the first billion years of the universe, stars and galaxies formed in the smallest dark matter halos, produced high-energy photons that reionized the intergalactic medium, and polluted the universe with the first heavy elements. Near-field cosmology probes this early era by observing nearby relic galaxies that have survived from ancient times. In particular, the elemental abundances of their old, metal-poor stars encode otherwise inaccessible information about the first stellar populations and first galaxy formation histories. Decoding these abundances requires connecting nuclear and stellar astrophysics to galaxy formation and hierarchical assembly. I will show how stellar abundances of metal-poor stars have shaped our current understanding of the rapid neutron-capture process (r-process), including how they inform future multi-messenger observations of kilonovae. The r-process can in turn be used to build our understanding of the high-redshift universe, including galaxy formation in the faintest dwarf galaxies and the hierarchical assembly of our Milky Way's stellar halo.

2020-07-24
15:00
Witnessing the Assembly of Planetary Systems with ALMA
Richard Teague (CfA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
ALMA has undoubtedly revolutionized our understanding of the planet formation environment, the protoplanetary disk. Images of the stunning gaps, rings and spirals traced by the dust in these disks point towards a population of young planetary systems caught in the very early stages of their formation. In parallel to these advances in imaging the dust component, a second revolution has been underway looking at the gas component of these disks. With ALMA we are able to obtain spatially and spectrally resolved spectra of simple molecular species, achieving signal-to-noise ratios in the hundreds. Such high quality spectra have enabled detailed explorations of the kinematics of these planetary nurseries, revealing extremely dynamic environments containing flow structures associated with on-going planet formation. I will present a series of results examining the dynamical structure of protoplanetary disks, demonstrating how we can measure rotation curves at a meters-per-second precision and how these can be used to infer the 6D structure of the disk. Combining these techniques, I will further show how we can now detect embedded planets within these disk, enabling a novel view of planet formation and trace the delivery of atmosphere-building material to these embedded planets. To conclude, I will discuss how we can expand these techniques to transform ALMA into a sub-mm planet hunting instrument, probing a truly unique region of parameter space previously inaccessible with current instrumentation and providing essential context for contemporary exoplanet demographics.

2020-07-24
15:00
Witnessing the Assembly of Planetary Systems with ALMA
Richard Teague (CfA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
ALMA has undoubtedly revolutionized our understanding of the planet formation environment, the protoplanetary disk. Images of the stunning gaps, rings and spirals traced by the dust in these disks point towards a population of young planetary systems caught in the very early stages of their formation. In parallel to these advances in imaging the dust component, a second revolution has been underway looking at the gas component of these disks. With ALMA we are able to obtain spatially and spectrally resolved spectra of simple molecular species, achieving signal-to-noise ratios in the hundreds. Such high quality spectra have enabled detailed explorations of the kinematics of these planetary nurseries, revealing extremely dynamic environments containing flow structures associated with on-going planet formation. I will present a series of results examining the dynamical structure of protoplanetary disks, demonstrating how we can measure rotation curves at a meters-per-second precision and how these can be used to infer the 6D structure of the disk. Combining these techniques, I will further show how we can now detect embedded planets within these disk, enabling a novel view of planet formation and trace the delivery of atmosphere-building material to these embedded planets. To conclude, I will discuss how we can expand these techniques to transform ALMA into a sub-mm planet hunting instrument, probing a truly unique region of parameter space previously inaccessible with current instrumentation and providing essential context for contemporary exoplanet demographics.

2020-07-17
15:00
Understanding nuclear star clusters in low-mass galaxies through M54
Mayte Alfaro (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Nuclear star clusters (NSCs) are the densest stellar system known in the universe. They are hosted by a high fraction of galaxies at different mass ranges. The characteristics exhibited by NSCs in low-mass galaxies are similar to high-mass and chemical complex globular clusters (GCs). This suggests that some NSCs can be found as Galactic GCs, as remnants of dwarf galaxies accreted by the Milky Way. M54, the NSC of the Sagittarius dwarf spheroidal galaxy is a remarkable example of this type of objects. As it still lies at the center of its host at a distance where resolved studies are possible (27 kpc), M54 provides the unique opportunity to understand low-mass galaxy nuclei in their original environments. In this talk, I will present an unprecedented detailed study of M54. Using a large MUSE data set covering out to ?2.5 effective radii of M54, we extracted ?6600 member stars recovering the star formation history of this NSC. We detected at least three stellar subpopulations whose origin can be explained as the result of the combination of different NSC formation mechanisms.

2020-07-17
15:00
Understanding nuclear star clusters in low-mass galaxies through M54
Mayte Alfaro (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Nuclear star clusters (NSCs) are the densest stellar system known in the universe. They are hosted by a high fraction of galaxies at different mass ranges. The characteristics exhibited by NSCs in low-mass galaxies are similar to high-mass and chemical complex globular clusters (GCs). This suggests that some NSCs can be found as Galactic GCs, as remnants of dwarf galaxies accreted by the Milky Way. M54, the NSC of the Sagittarius dwarf spheroidal galaxy is a remarkable example of this type of objects. As it still lies at the center of its host at a distance where resolved studies are possible (27 kpc), M54 provides the unique opportunity to understand low-mass galaxy nuclei in their original environments. In this talk, I will present an unprecedented detailed study of M54. Using a large MUSE data set covering out to ?2.5 effective radii of M54, we extracted ?6600 member stars recovering the star formation history of this NSC. We detected at least three stellar subpopulations whose origin can be explained as the result of the combination of different NSC formation mechanisms.

2020-07-10
15:00
Exploring the sources of cosmic reionization
: Maxime Trebitsch (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Cosmic reionization is one of the last major milestones in the evolution of the Universe. It has only taken one billion years for the bulk of the hydrogen in the Universe to be fully ionized by the radiation produced by early galaxies and quasars. While significant progress has been made in the recent years, completing the census of these ionizing sources is still a major challenge on both the observational and theoretical sides.
In this talk, I will discuss how radiation hydrodynamical simulations can be used to study the properties of the first galaxies and AGN with a particular focus on their relative role in reionizing the Universe.

2020-07-10
15:00
TBA
Rebecca Bowler (Oxford)
Königstuhl Kolloquium
TBA,
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Abstract

TBA
KoCo Signature Speaker

2020-07-10
15:00
Exploring the sources of cosmic reionization
: Maxime Trebitsch (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Cosmic reionization is one of the last major milestones in the evolution of the Universe. It has only taken one billion years for the bulk of the hydrogen in the Universe to be fully ionized by the radiation produced by early galaxies and quasars. While significant progress has been made in the recent years, completing the census of these ionizing sources is still a major challenge on both the observational and theoretical sides.
In this talk, I will discuss how radiation hydrodynamical simulations can be used to study the properties of the first galaxies and AGN with a particular focus on their relative role in reionizing the Universe.

2020-07-03
15:00
Multiplicity properties of pre-supernova massive stars in the Magellanic Clouds
Lee Patrick (U. de Alicante)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract

Most massive stars reside in multiple systems with ?70% expected to interact during their lifetimes. These interactions have profound effects on the evolution of the stars in such systems and the nature of their subsequent supernova explosions, as well as on the formation of stellar mass black hole?black hole binaries. Red supergiant stars represent the final evolutionary stage of the majority of massive stars before supernova and remain the only confirmed progenitors to Type IIp SN. What is known about the multiplicity properties of this phase of evolution is either theoretical, extrapolated from earlier evolutionary phases or based on a very small sample of stars. I review the various evolutionary paths towards a RSG multiple system and present the latest observational and theoretical results on the multiplicity of RSGs, concentrating on the Large and Small Magellanic Clouds. We find a significantly smaller multiplicity fraction for RSGs than their evolutionary descendants. I discuss the implications of this important result and the limitations of the current observations where I stress the need for future high-precision and -accuracy spectroscopic studies of the Magellanic Clouds.



See More \;from Eva Schinnerer

2020-07-03
15:00
Multiplicity properties of pre-supernova massive stars in the Magellanic Clouds
Lee Patrick (U. de Alicante)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract

Most massive stars reside in multiple systems with ?70% expected to interact during their lifetimes. These interactions have profound effects on the evolution of the stars in such systems and the nature of their subsequent supernova explosions, as well as on the formation of stellar mass black hole?black hole binaries. Red supergiant stars represent the final evolutionary stage of the majority of massive stars before supernova and remain the only confirmed progenitors to Type IIp SN. What is known about the multiplicity properties of this phase of evolution is either theoretical, extrapolated from earlier evolutionary phases or based on a very small sample of stars. I review the various evolutionary paths towards a RSG multiple system and present the latest observational and theoretical results on the multiplicity of RSGs, concentrating on the Large and Small Magellanic Clouds. We find a significantly smaller multiplicity fraction for RSGs than their evolutionary descendants. I discuss the implications of this important result and the limitations of the current observations where I stress the need for future high-precision and -accuracy spectroscopic studies of the Magellanic Clouds.



See More \;from Eva Schinnerer

2020-06-26
15:00
Zooming into the blast furnace - A close look into the molecular gas in the NGC253 starburst
Nico Krieger (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract

n this talk I will present the results of my work as a PhD student over the past four years
at MPIA. In starbursts, such as the nearby galaxy NGC253, intense star formation creates


conditions that are believed to resemble those in high-z galaxies, and the strong
stellar feedback drives galaxy-scale outflows. We observed the molecular gas in
this extreme starburst environment in NGC253 at the unprecedented spatial

resolution of 2.5 pc with ALMA. Using this data, we study the molecular outflow
in detail, zoom into NGC253's central super star clusters and compare its
starburst to the similar but more quiescent center of the Milky Way.

2020-06-26
15:00
Zooming into the blast furnace - A close look into the molecular gas in the NGC253 starburst
Nico Krieger (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract

n this talk I will present the results of my work as a PhD student over the past four years
at MPIA. In starbursts, such as the nearby galaxy NGC253, intense star formation creates


conditions that are believed to resemble those in high-z galaxies, and the strong
stellar feedback drives galaxy-scale outflows. We observed the molecular gas in
this extreme starburst environment in NGC253 at the unprecedented spatial

resolution of 2.5 pc with ALMA. Using this data, we study the molecular outflow
in detail, zoom into NGC253's central super star clusters and compare its
starburst to the similar but more quiescent center of the Milky Way.

2020-06-19
15:00
Uncovering the Onset of Planet Formation in Young Protostellar Disks
Sarah Sadavoy (Queens University/Canada)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Planets form in disks of dust and gas around young stars, where the growth of the dust grains are the first steps in the planet formation process. Constraining the onset of grain growth and the conditions under which it is favourable has been challenging in part because there has been a lack of observational tests that can be used to measure grain sizes in disks. Dust polarization from self-scattering processes offers a new opportunity to constrain grain growth in young disks, and thanks to the development of high resolution polarization capabilities, such observations are now possible. In this presentation, I will present an overview of the polarized self-scattering process and how it can be used to infer dust grain properties in disks. I will also highlight recent observational studies that have detected polarized self-scattering in young disks from ALMA and the VLA and the implications of these signatures for dust grain growth at early times (< 0.5 Myr). I will also discuss the challenges with using this mechanism and offer steps for what still needs to be done to utilize dust self-scattering to identify the building blocks for planets.

2020-06-19
15:00
TBA
Sera Markoff (UVA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

KoCo Signature Speaker

2020-06-19
15:00
Uncovering the Onset of Planet Formation in Young Protostellar Disks
Sarah Sadavoy (Queens University/Canada)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Planets form in disks of dust and gas around young stars, where the growth of the dust grains are the first steps in the planet formation process. Constraining the onset of grain growth and the conditions under which it is favourable has been challenging in part because there has been a lack of observational tests that can be used to measure grain sizes in disks. Dust polarization from self-scattering processes offers a new opportunity to constrain grain growth in young disks, and thanks to the development of high resolution polarization capabilities, such observations are now possible. In this presentation, I will present an overview of the polarized self-scattering process and how it can be used to infer dust grain properties in disks. I will also highlight recent observational studies that have detected polarized self-scattering in young disks from ALMA and the VLA and the implications of these signatures for dust grain growth at early times (< 0.5 Myr). I will also discuss the challenges with using this mechanism and offer steps for what still needs to be done to utilize dust self-scattering to identify the building blocks for planets.

2020-06-12
15:00
atomic diffusion and mixing at the origin of chemical abundance variations.
Ekaterina Semenova (MPIA):We still do not understand physics of stars
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The past decade revolutionised studies of Galactic structure and evolution. Large spectroscopic surveys, such as GALAH, APOGEE, RAVE, and LAMOST delivered spectra and chemical abundances for millions of stars in the Galaxy. \;However, this development also brought to light interesting peculiarities, which may have profound consequences for stellar astrophysics. \;It is common to assume that the surface abundances, determined by means of stellar spectroscopy, represent the composition of the ISM from which the star was born.  \;However, this assumption is controversial. Recent observational and theoretical studies suggest that individual chemical elements <\;<\;migrate>\;>\; inside the stars. The rate and direction of this migration depend on the chemical mixture, on the mass of a star and on its age, and, foremost, on the mass and atomic properties of the chemical element itself. This implies that the surface composition of a star is not equal to its birth composition. \;Given the physical diversity of transport processes, the question is: how can we constrain this migration? In this talk, I will give an overview of the problem from the observer's and modeller's perspective. I will furthermore, touch upon our recent findings, based on high-quality analysis of the Gaia-ESO survey data with 3D Non-LTE models. I will outline the physics behind the transport of elements in star, discuss the constraints that can be obtained from observations, and highlight broader consequences for studies of chemical enrichment of stellar populations in the Milky Way and in other galaxies

2020-06-05
15:00
Light Element Inhomogeneities and Multiple Populations in Globular Clusters
Jeffrey Gerber (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract

Globular clusters (GCs) are massive star clusters orbiting in the halo of the Galaxy and are some of the first objects to form in the Milky Way. Due to their old ages and large numbers of stars they are perfect objects to learn about the formation history of our Galaxy and the evolution of low mass stars. However, studies have shown that GCs are not simple homogeneous populations, but rather are home to multiple populations of stars with differing abundances in light elements such as C, N, O, and Na. In this colloquium, I will present research from my dissertation, which used a large data set to study these populations and the abundances of C and N in the evolved stars of these objects. We focus on three globular clusters, M53, M10, and M71. Our sample includes low resolution spectra of 100-150 stars in each cluster that span a large range of magnitudes, which allows us to study the effects of evolutionary processes on the surface abundances of C and N. We classify stars based on their N abundances into a N-normal and a N-enhanced population. Our results show that two populations of stars are found in all three clusters with both populations appearing in a similar ratio in all stages of evolution. We also find that stars in both populations experience the same rate of surface C depletion and N enhancement as they evolve. Finally, we compare our method of classifying stars to other methods present in the literature, and find no anomalous abundance patterns, and determine that all methods used on the three clusters studied agree on the number of populations in each cluster.

2020-05-29
15:00
Combining astrophysics and geology to study the formation of Earth and Venus
Seth Jacobson (Michigan State Uni)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The accretion of Earth is a mysterious era in geologic history without any surviving rock record. However, this is when Earth's bulk geochemistry and geophysical structure was established. Using sophisticated astrophysical-geological modeling, we can reconstruct this era, date important events such as the Moon-forming event, and determine basic characteristics of the nascent protoplanetary disk. By considering the consequences for Earth, we can better understand the stark contrast of Venus--a planet without a planetary magnetic field, without plate tectonics, and without a Moon. This earliest eon which lies at the intersection of astrophysics and geology had profound consequences for life on Earth that are just beginning to be understood.

2020-05-22
15:00
Tracing Historic Mass Loss from Evolved Stars with Thermal Emission from Cold Dust
Thavisha Dharmawardena (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Evolved stars play a key role in the life cycle of dust in the universe. Through strong winds and supernovae they inject the material reprocessed in their cores to the interstellar medium, replenishing the interstellar medium with heavy elements. As evolved stars are so numerous they are extremely effective in this role. In this talk I will explore the role of historic mass loss. The typical treatment of evolved stars only accounts for present day mass loss or assumes they undergo constant mass loss throughout their lifetime. Historic mass loss can be effectively traced using thermal emission from the dust which cools down as it moves away from the central star. We exploit Herschel/PACS and JCMT/SCUBA-2 observations to study this historic mass loss. These two sets of observations are especially powerful, tracing the radial variation in the circumstellar envelopes of evolved stars. We establish the presence of variations in mass loss for a sample of Milky Way evolved stars which can not be ignored when applied to galactic models. In addition to this, we explore variability at sub-mm wavelengths for a small sample of evolved stars, including Betelgeuse during its recent minimum, to understand the relationship between the sub-mm variability and the circumstellar envelope. Finally I will introduce an overview of my current work at MPIA which focuses on modelling the 3D distribution of dust in the Milky Way by exploiting data from large surveys including Gaia and SDSS.

2020-05-15
15:00
Supermassive black holes in cosmological simulations
Melanie Habouzit (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Supermassive black holes of million solar mass and above are commonly hosted by massive galaxies, but are also present in local dwarf galaxies. Black holes are a fundamental component of galaxies and galaxy evolution, but their origin is still far from being understood. Large-scale cosmological simulations of 100 cMpc box side length are crucial to understand BH growth and their interplay with their host galaxies. In a new study, we compare the black hole population of six of these large-scale cosmological simulations (Illustris, TNG100, TNG300, Horizon-AGN, EAGLE, and SIMBA). For the first time, our homogenous analysis of these simulations allows us to explore how the simulation sub-grid models affect the build-up of the BH population and their correlations with galaxies properties. The next two decades will be dedicated to the exploration of the high-redshift Universe with upcoming space missions such as LynX, Athena, JWST, WFIRST. I will also present how we can use cosmological simulations with physical models for BH formation to prepare these missions and maximize their scientific return.

2020-05-08
15:00
Dynamical fingerprints in the exoplanets sample
Gabriele Pichieri (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
25 years of observations have produced a large sample of exoplanets, many hosted by the same star in multiplanetary systems, and their orbital periods are one of the most intriguing distributions. An interesting and puzzling feature is the dearth of mean motion resonances, which are instead a predicted outcome of formation scenarios for the very common Super-Earth-type planets: although we do observe some resonant chains, most systems are not in resonance. In this presentation I will describe the main aspects of mean motion resonances, which also allows to understand why they are a preferred outcome for Super-Earths in the protoplanetary disc phase. Then, I will discuss how planetary instabilities in the Gyr evolution after the disc phase can reconcile this scenario with the observed exoplanetary architecture. Thus, I will present a novel dynamical mechanism which can be responsible for breaking the resonant chains. Finally, two other features of the period ratio distribution will be discussed: the population of multi-systems with period ratios wide of exact resonant commensurability, and the role of closely-packed systems.

2020-04-24
15:00
From exoplanet atmospheres to planet formation
Paul Moliere (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract


If one wants to know more about exoplanets than their most basic properties (such as mass and radius), turning to spectroscopy is essential. Spectra probe the planetary atmospheres and encode their composition, temperature structure and dynamics. Such observations are therefore crucial for understanding the atmospheric state of exoplanets. In addition, they may help us to unlock how planets form, namely by linking atmospheric composition to the planets' accretion of different building blocks from the circumstellar disk. In this talk I will give a summary on the techniques and challenges of atmospheric characterization. I will then present my own work towards the understanding of exoplanet atmospheres, and how this may be used for constraining planet formation in the future.


2020-04-17
15:00
From supernova rates and delays to progenitors and nucleosynthesis history
Dan Maoz (Tel-Aviv U.)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
Supernovae are Nature's almost-exclusive way of producing the elements from oxygen to iron. Roughly half of the world's iron was formed in so-called Type Ia supernovae (SNe Ia), the thermonuclear explosions of some white dwarf stars. SNe Ia have gained fame as distance indicators that first revealed the dark-energy-driven accelerating universal expansion. However, the precise identity of the exploding systems in SNe Ia, and their explosion mechanism, are major unsolved puzzles. Valuable clues are provided by the delay-time distribution (DTD): the spread of times between the formation of a stellar population and the explosion of some of its members as SNe Ia. I will show how recent attempts to measure the DTD, combined with other evidence, suggests that SNe Ia result from double white-dwarf systems that lose orbital energy to gravitational waves, merge, and explode. In parallel, I will show ongoing work to take the census of the Milky Way's double-white-dwarf systems, before they merge. The observed DTD permits attempting a reconstruction of the history of element creation in our Galaxy and in the Universe as a whole.

2020-04-03
15:00
The importance of environment for protoplanetary discs
Andrew Winter (ARI)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract

Although most models aiming to synthesise the observed exoplanet architectures consider a protoplanetary disc evolving in isolation, this does not reflect the physical reality for many discs. Since stars form in regions of enhanced stellar density, feedback mechanisms play an important role. In particular, UV fields heat the disc and drive a photoevaporative wind, depleting the disc and decreasing the dispersal time-scale. I review the demographics of local star forming regions, and compare them to those regions that are the focus of observational studies of protoplanetary discs, demonstrating that well-studied discs are not typical. I present the evidence for the depletion of discs in various regions by external photoevaporation. Finally, I discuss how, as well as being an important consideration in understanding exoplanet populations, external photoevaporation can be used as a probe of both star formation and disc physics.

2020-03-27
15:00
TBD
Jonathan Henshaw (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2020-03-27
15:00
We still do not understand physics of stars: atomic diffusion and mixing at the origin of chemical abundance variations
Ekaterina Semenova (MPIA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract

The past decade revolutionised studies of Galactic structure and evolution. Large spectroscopic surveys, such as GALAH, APOGEE, RAVE, and LAMOST delivered spectra and chemical abundances for millions of stars in the Galaxy. \;
However, this development also brought to light interesting peculiarities, which may have profound consequences for stellar astrophysics. \;

It is common to assume that the surface abundances, determined by means of stellar spectroscopy, represent the composition of the ISM from which the star was born.  \;However, this assumption is controversial. Recent observational and theoretical studies suggest that individual chemical elements <\;<\;migrate>\;>\; inside the stars. The rate and direction of this migration depend on the chemical mixture, on the mass of a star and on its age, and, foremost, on the mass and atomic properties of the chemical element itself. This implies that the surface composition of a star is not equal to its birth composition. \;
Given the physical diversity of transport processes, the question is: how can we constrain this migration?

In this talk, I will give an overview of the problem from the observer's and modeller's perspective. I will furthermore, touch upon our recent findings, based on high-quality analysis of the Gaia-ESO survey data with 3D Non-LTE models. I will outline the physics behind the transport of elements in star, discuss the constraints that can be obtained from observations, and highlight broader consequences for studies of chemical enrichment of stellar populations in the Milky Way and in other galaxies.

2020-03-27
15:00
Understanding the gas dynamics in the central 3 kpc of the Milky Way
Mattia Sormani (ZAH/ITA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
I will give an introduction to the gas dynamics in the central region (R<3kpc) of the Milky Way, which is characterised by strong non-circular motions driven by the non-axisymmetric gravitational potential of the Galactic bar. After reviewing the basic theoretical tools, I will discuss how these can be used to interpret observations, and in particular the longitude-velocity maps of CO, HI and other tracers in the region | | | < 30 degrees. I will then discuss several applications, for example how this can be used to constrain the properties of the bar, and to estimate the accretion rate onto the Central Molecular Zone (the star-forming nuclear ring at R~150pc). Finally, I will highlight some open questions and directions of future research.

2020-03-27
15:00
Understanding the gas dynamics in the central 3 kpc of the Milky Way
Mattia Sormani (ZAH/ITA)
Königstuhl Kolloquium
Via zoom link. Please contact organisers if you need the zoom information.,
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Abstract
I will give an introduction to the gas dynamics in the central region (R<3kpc) of the Milky Way, which is characterised by strong non-circular motions driven by the non-axisymmetric gravitational potential of the Galactic bar. After reviewing the basic theoretical tools, I will discuss how these can be used to interpret observations, and in particular the longitude-velocity maps of CO, HI and other tracers in the region | | | < 30 degrees. I will then discuss several applications, for example how this can be used to constrain the properties of the bar, and to estimate the accretion rate onto the Central Molecular Zone (the star-forming nuclear ring at R~150pc). Finally, I will highlight some open questions and directions of future research.

2020-03-20
15:00
The mass budget of planet-forming disks
Anna Miotello (ESO)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract



Protoplanetary disks are thought to harbor the sites of on-going planet formation. Therefore, it is important to understand the spatial distribution, the physical and chemical properties of protoplanetary building blocks to understand planet formation mechanisms and their planetary system demographics. In this context, the total disk mass and the disk surface density distribution are probably the most fundamental properties. Determining the total disk mass \;? \;which is dominated by the gaseous component \;? \;has proven to be very challenging. On one hand dust-based disk masses depend on the assumptions on the dust properties, on the optical depth of the continuum emission and on the gas/dust ratio, and on the other hand molecular hydrogen is invisible at mm wavelengths. Large surveys of disks carried out with ALMA in different star forming regions have targeted CO isotopologues as gas mass tracers. A result that is common to these surveys is that CO emission from disks is fainter than expected. As a consequence, the overall CO-based gas-masses are very low, and global gas/dust mass ratios are much lower than the expected interstellar-medium value of 100. This may be interpreted as lack of gas due to fast disk dispersal, or as lack of volatile carbon that leads to faint CO lines. After summarizing the results from different ALMA disk surveys and their implications, I will present alternative observational strategies which may help us to disentangle between the gas dispersal scenario and the chemical evolution hypothesis, for example using HD and hydrocarbon observations. Finally, I will present how current and future observations could be used to constrain the disk surface density distribution.

2020-03-20
15:00
The colourful past and dark side of galaxies unveiled through population-dynamics of their stars
Glenn van de Ven (U. Vienna)
Königstuhl Kolloquium
Via zoom. Please contact organisers if you need zoom information.,
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Abstract

Driven by gravity, galaxies continuously grow through accretion of smaller systems. Stellar streams are nice illustrations of this hierarchical build-up, but the accreted stars quickly disperse. I will present advanced dynamical models that can convert the observed positions and velocities of the accreted stars to phase-space quantities like energy and angular momentum which remain conserved. In addition, these models can include the observed chemical properties of stars which are also conserved. The resulting population-dynamical models allow us then to uncover even those accretion events which are now fully dispersed. At the same time, these models also accurately constrain the total mass distribution, including a central black hole and dark matter halo.



I will illustrate how these models make optimally use of observations to unveil the dark side and colour past of galaxies: from accurate measurements of their dark halo, to unveiling the formation history of their disk and spheroid components, to uncovering the satellite accretion history. By the end, I aim to have demonstrated that these models provide a unique bridge between the studies of resolved stars in the Milky Way and integrated-light of high-redshifts galaxies. Together with direct coupling to state-of-the-art galaxy formation simulations, these population-dynamical models enable us to uncover the hierarchical build-up of galaxies in a cosmological context.

2020-03-13
15:00
On the radial structure and gas release of exoKuiper belts
Sebastian Marino (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Planetary systems are not only composed of planets but also of belts of minor bodies with sizes ranging from ?m to km, analogous to the asteroid and Kuiper belts. This non-planetary component provides unique information on the formation, architecture, dynamics and evolution of planetary systems, as well as playing an important role in the delivery of volatiles to Earth-like planets. Collisions within these belts grind down solids resulting in high dust levels that are readily detectable around 30% of stars. In this colloquium, I will summarise the state of the art in the study of "exoKuiper" belts and show how my research at MPIA fits in this subfield of planetary research. I will show how ALMA has revolutionised the field by providing images at an unprecedented resolution of this type of circumstellar dust which traces the distribution of their parent km-sized planetesimals. Using ALMA I have characterised the radial structure in these belts, finding annular gaps that hint at the presence of Neptune analogues clearing their orbits at tens of au. ALMA has been also the first instrument capable of detecting and imaging circumstellar gas in these mature systems. This gas is of secondary origin and released by volatile-rich planetesimals (exocomets) in the same collisions that produce the observed dust. At MPIA, I have developed the first population synthesis model to study the evolution of this gas to constrain the timescales at which it viscously evolves and how it could affect the atmospheres of planets on orbits closer to the star.

2020-03-06
15:00
Mapping Milky Way Dust in 3D using Stars
Greg Green (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Many precision measurements in astronomy depend on a careful treatment of dust reddening. Historically, two-dimensional maps of dust based on far-infrared thermal emission, such as the SFD and Planck maps, have found extensive use. However, an alternative method for measuring dust extinction relies on stellar photometry. Unlike far-infrared dust emission, stars can be used to trace the distribution of dust along the distance axis, as well as variations in the wavelength-dependence of extinction. Dust maps based on stellar photometry have additional desirable properties, such as the fact that their errors should be uncorrelated with large-scale structure.
I will discuss a 3D map of dust in the Northern Hemisphere, based on photometry from Pan-STARRS 1 and 2MASS, as well as astrometry from Gaia. I will also discuss ongoing work to extend this map to the South using the recently completed DECaPS survey, which was conducted with the Dark Energy Camera on the 4m Blanco telescope at CTIO. This work relies on accurate models of stellar photometry. In closing, I will therefore discuss my work to improve these models and understand variation in the dust extinction spectrum by applying machine learning methods to a combination of stellar spectroscopy, photometry and astrometry.

2020-02-28
15:00
Orion and the solar neighbourhood
Eleonora Zari (MPIA):Surveying young stars with Gaia
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
OB associations are loose groups of young, massive stars. They constitute the last stage of the massive star
formation process, and the context in which new stars are formed. Although OB associations have long been studied, it is not clear how they form and disperse in the field and what are the characteristics of their stellar populations.
The data of the Gaia satellite are crucial to unravel the structure and star formation history of the young associations, as they allow to study their spatial structure, kinematics, and ages with unprecedented precision.
In this talk, I will discuss the properties of the stellar groups in the Orion OB association, and
I will describe the three dimensional arrangement of young stars in the solar neighbourhood,
providing a view of the spatial configuration of young star forming regions within 500 pc from the Sun.

2020-02-21
15:00
The Origin of Stellar Masses
Mark Krumholz (ANU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The mass distribution of newborn stars, known as the initial mass function (IMF), has a distinct peak at a mass slightly less than that of the Sun. This characteristic stellar mass appears to be nearly invariant across a huge range of star-forming environments within and beyond our Galaxy, and seems to have changed little over most of cosmic time. Explaining its origin and universality is one of the oldest problems in theoretical astrophysics, but a fully successful theory eludes us even today. In this talk, I review theoretical attempts to explain the characteristic mass of stars, and discuss recent progress suggesting that we may be within reach of a solution.

2020-02-14
15:00
Mapping the hot Universe: eROSITA on SRG and its followup programs with SDSS-V and 4MOST
Andrea Merloni (MPE)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The emergence of the three-dimensional structure of the cosmic web over the history of the Universe displays very distinctive features when observed in X-rays, where both the most massive collapsed structure (clusters of galaxies) and the most energetic events in the life of galaxies (AGN and Quasars) reveal themselves unambiguously.

The next generation of wide-area, sensitive X-ray surveys designed to map the hot Universe will be heralded by eROSITA (extended ROentgen Survey with an Imaging Telescope Array), the core instrument on the Russian-German Spektrum-Roentgen-Gamma (SRG) mission, successfully launched in July 2019. On December 8, after completion of its Calibration and Performance Verification phase, SRG/eROSITA has begun its four-years program dedicated to surveying the entire sky eight times in the energy range ~0.2-7 keV.

The high sensitivity, large field of view, high spatial resolution and high survey efficiency of eROSI

2020-02-07
15:00
Stars, Gas, and Dust in the Triangulum Galaxy
Thomas Williams (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The Triangulum Galaxy (M33), is the third nearest spiral galaxy to us (behind the Milky Way and Andromeda), but is an interesting contrast to those galaxies. With a half-solar metallicity, and a much higher star-formation efficiency, the properties of M33 seem to be significantly different to the other 2 massive spirals in our Local Group, and may offer us more of a look at a ?younger', or higher redshift galaxy. I'll be talking about the 3 projects that made up my thesis, studying the interplay between the dust, gas, and stars in M33.

Firstly, I will present a study of the resolved star-formation law (or Kennicutt-Schmidt law) ? how this varies with the resolution it is measured at, and the gas tracer that is used. Secondly, using new SCUBA-2 PI observations of M33, I have created a dust-selected GMC catalogue, studying the gas-to-dust ratios (GDRs) and CO conversion factors in these clouds, as well as hunting for molecular hydrogen that CO may miss. Finally, using the data I have brought together over the course of my PhD, I have built a radiative transfer model of M33. This has been to study the sources of dust heating, and the scale at which a local dust-energy balance (i.e. the area at which the emission from dust is from starlight in that same area) is an acceptable assumption.

2020-01-31
15:00
The Demographics of Protoplanetary Disks: from Lupus to Orion
Sierk van Terwisga (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
In recent years, ALMA has opened up unprecedentedly detailed views of
the properties of planetary disks, and on their links to planetary
systems: the deep, high-resolution images of TW Hya, HL Tau and the
DSHARP survey are famous examples. But what does a 'typical'
protoplanetary disk look like -- and how do its properties change over
time, and in different environments?
ALMA's unique combination of speed and sensitivity enables us to survey
large samples of disks relatively quickly, and describe some of the key
parameters of protoplanetary disks from a population-level view.
In this colloquium, I will discuss surveys of protoplanetary disks in
Lupus, Orion A, and Orion B, focusing on the radii and masses of disks.
By comparing these regions' disks to each other, and to other surveyed
populations, we can begin to disentangle the competing impacts of
environment and age on the evolution of circumstellar material.

2020-01-24
15:00
The outcome of massive star formation
Maria Ramirez-Tannus (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Massive stars play a crucial role in the Universe. They shape their surroundings by injecting large amounts of energy and momentum and they produce new, heavy elements that are the building blocks of new stars, planets, and life. They are usually observed in close binaries. Due to the lack of observations covering the earliest stages of their lives, the formation process of massive (binary) stars is poorly understood. I will present observational studies of the outcome of massive star formation. I will show the first spectroscopically confirmed population of massive pre-main sequence stars in the giant HII region M17 where we measured their temperature, luminosity, radius, and projected radial velocity. I will discuss their multiplicity properties and show that the young stars in M17 have a very low radial velocity dispersion in comparison to somewhat older stellar clusters of similar mass. I will present evidence for the hypothesis that massive stars are formed in binaries with wide orbits that shrink in the first few million years of evolution. Finally, I will present ongoing projects to test the wide binary hypothesis.

2020-01-17
15:00
Merger-triggered Star Formation: Where and How?
Hsi-An Pan (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Galaxy interactions are often accompanied by an enhanced global star formation rate (SFR). The enhanced global SFR has been attributed to the formation of non-axisymmetric structures that torque significant amounts of gas into the central regions, initiating an intense nuclear starburst. Yet there is mounting evidence for extended starburst in interacting galaxies.

The talk will show an empirical picture of the spatial extent of merger-triggered star formation as a function merger sequence using data from the integral field spectroscopy (IFS) survey MaNGA. In addition, we also investigate the molecular gas properties to better understand what causes the enhanced star formation in galaxy mergers. This is the first time that the spatial extent of merger-triggered star formation and the dependence of molecular gas properties on merger sequence/configurations are probed statistically with a relatively large sample and with a carefully-selected control sample for individual galaxies.

2019-12-06
15:00
Characterizing the formation mechanisms of protostellar disks: observations and models
Anaelle Maury (CEA/Saclay)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Understanding the first steps in the formation of stars and protoplanetary disks is a great unsolved problem of modern astrophysics. Observationally, the key to constraining theoretical models lies in high-resolution studies of the youngest protostars. \;
I will present the state of the art regarding observations and modeling of the youngest protostellar disks, observed less than 0.1 Myrs after the onset of protostellar formation. \;
In a first part, I will show how our millimeter dust continuum interferometric data suggests that most (>\;75%) protostellar disks observed less than 0.1 Myrs after the onset of protostellar formation are only found at very small radii <\;60 au, which favors magnetized models for protostellar disk formation. I will also present our ALMA observations of a very young solar-type protostar suggesting a disk is currently forming in counter-rotation with respect to the protostellar core rotation, and discuss potential scenarii to understand this oddity. I will show our SMA and ALMA observations of the magnetic field topology in a sample of young protostars and compare all observed protostellar properties to the typical outcome of models for protostellar formation. I will argue that our observations of small disks, counter-rotating disks and organized magnetic fields in the youngest star-forming cores question the established paradigm of disk formation as a simple consequence of angular momentum conservation during the main accretion phase: they instead highlight the need to investigate magnetized models in order to unveil the mechanisms responsible for protostellar disk properties.
In a second part, I will show both our observations and models of the dust continuum emission call for significant grain growth (grains larger than 10 microns and up to submillimeter sizes) at radii 100-1000 au in the protostellar envelopes observed less than tenth of a million years after the onset of collapse. I will describe new avenues to explore dust pristine properties and describe better in the future, for example, the initial conditions for the formation of planetesimals.

2019-11-29
15:00
D. Liu, M. Rugel & I. Smirnova-Pinchukova
Patzer Colloquium (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
D. Liu, M. Rugel & I. Smirnova-Pinchukova will give each a 20min presentation of the Patzer-award paper. Afterwards, we will have a reception to celebrate the winners.

2019-11-22
15:00
Tracing early nucleosynthesis in-/directly in the Universe
Camilla Hansen (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Understanding how the heavy elements are produced in the early Universe remains one of the open questions in astrophysics. We seek to trace the first chemical enrichment from the First Stars (Pop III stars), which are long gone, and which we due to observational limitations cannot observe directly. Hence, we are forced to explore the properties and physics of this first population of stars through indirect measurements of the second generation stars. Bona fide second generation stars preserve to a great extent the gases and thus the traces of the Pop III stars in their surfaces. As we observe the old metal-poor stars in greater numbers we see that these are typically C-rich and often contain varying amounts of heavy elements. The amount of heavy element content is a direct tell about the Carbon Enhanced Metal-Poor (CEMP) stars nature and origin. It therefore becomes of utmost importance to understand the source of the heavy element production. Until the recent years, the heavy element nucleosynthesis could only be explored indirectly, however, thanks to a-LIGO's gravitational wave detections and the following ground-based observations of the electromagnetic wave signal, we can for the first time directly study the formation of radioactive heavy element nucleosynthesis taking place in the rapid neutron-capture process hosted by a kilonova. I will describe the manifold nature of CEMP stars, their origin, and link this to the r-process.

2019-11-15
15:00
New Light on Standard Candles: Putting Hubble Constant Measurements to the Test using High-precision Observations of classical Cepheids
Richard Anderson (ESO Garching)
Königstuhl Kolloquium
MPIA lecture hall,
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Abstract
Recent research has established a remarkable discord among determinations of Hubble's constant, H0, that measures the local expansion rate of the Universe. The value of H0 measured using an empirical distance ladder is 9% larger than the value inferred from precise observations of the oldest observable radiation, the Cosmic Microwave Background, using a cosmological model. The 4.2 sigma significance of these discordant H0 values is at least remarkable\; at most, it could indicate a need to modify cosmology, placing us a the brink of a possible breakthrough in physics. However, systematic uncertainties involved in H0 measurements require more detailed inspection before new physics can be credibly invoked.

Here I present research aimed at improving the astrophysical basis of the empirical distance ladder and mitigating systematic uncertainties related to classical Cepheids. First, I present the Geneva Cepheid Radial Velocity Survey (GE-CeRVS), which is used to support accurate parallax measurements and has uncovered previously unknown spectral variability phenomena that lead to systematic errors of Baade-Wesselink type distances. Next, I briefly describe the effects of rotation on the evolution of Cepheids and why rotation is relevant for testing evolutionary models and inferring Galactic structure. In the final part, I discuss distance scale biases arising from differences between local and distant Cepheid populations that are becoming increasingly important as the distance ladder is being extended to include ever more distant supernova host galaxies.

2019-11-08
15:00
Dense gas and star formation in nearby starburst galaxies with ALMA
Christine Wilson (McMasters)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
With its high sensitivity, excellent angular resolution, and wide spectral coverage, ALMA is revolutionizing our view of galaxies in the nearby universe. ALMA is particularly important for studying the dense molecular gas that is the fuel for star formation. Radio continuum emission from ALMA is also an important measure of the star formation rate, particularly in galaxies with high visual extinction such as starburst galaxies and luminous infrared galaxies. Finally, the ALMA archive contains an ever-growing collection of data that can be mined and combined to produce large samples of targets that can match or exceed the amount of observing invested in a single ALMA large program. I will describe our work on the link between dense gas and star formation for a sample of 9 nearby galaxies from the ALMA archive, which includes measuring the resolved Kennicutt-Schmidt star formation law at extreme star formation rate surface densities and identifying a new molecular line that appears to be an excellent tracer of the densest star forming gas.

2019-10-25
15:00
Revealing the mysteries of gas giant planets
Ravit Helled (Zurich)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Planets are common and mysterious astrophysical objects. Giant planets are key planets to investigate because they have a critical role in shaping the architecture of young planetary systems and their composition provides information on the physical and chemical properties of proto-planetary disks, the birth places of planets.
Gas giants are thought to have heavy-element cores in their deep interiors, and the division into a core and hydrogen-helium envelope is applied in both formation and internal structure models.
However, recent giant planet formation and evolution simulations show that this is an over-simplification. First, I will present updated formation and evolution models that follow the heavy-element distribution imply that giant planets are inhomogeneous and are expected to have dilute/fuzzy cores. I will then present updated structure models of Jupiter that fit the recent measurements of the Juno mission and discuss the importance of these results for our understanding of Jupiter's origin, and for the characterization of giant exoplanets.

Signature Speaker

2019-10-18
15:00
Accretion and Feedback in High-Mass Star Formation
Rolf Kuiper (Uni Tuebingen/MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
In the course of their accretion phase, massive (proto)stars impact their natal environment in a variety of feedback effects such as thermal heating, MHD-driven protostellar jets and outflows, radiation forces, and photoionization / HII regions. Here, I present our most recent simulation results in terms of the relative strength of the feedback components and the size of the reservoir from which the forming stars gain their masses. For the first time, these simulations include all of the feedback effects mentioned above which allows us to shed light on the physical reason for the upper mass limit of present-day stars. Furthermore, we predict the fragmentation of massive circumstellar accretion disks as a viable road to the formation of spectroscopic massive binaries and the recently observed strong accretion bursts in high-mass star forming regions.

To advertise our latest code development, I will also overview the most recent results obtained in a variety of other astrophysical research fields from the formation of embedded Super-Earth planets' first atmospheres (Cimerman et al. 2017, MNRAS) to the formation of the progenitors of the first supermassive black holes in the early universe (Hirano et al. 2017, Science).

2019-10-11
15:00
Towards more robust and explainable neural nets: Beyond the black box
D. Finkbeiner (CfA)
Königstuhl Kolloquium
MPIA lecture hall,
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Abstract
Deep neural nets have achieved ever greater successes in recent years, but there is still a pervasive sentiment in our field that "they are black boxes" and "we will never understand them." A thorough understanding remains elusive, but we can conceptualize what a neural net is doing using familiar tools and concepts, such as probability distribution functions, fitting functions, and Bayesian statistics. We can leverage results from the field of "Adversarial AI" to study important failure modes, and learn how to mitigate them by addressing the underlying cause of failure. By training neural networks better, using them better, and evaluating their performance better, we may be able to apply these powerful tools to astronomical problems with sufficient rigor to make them broadly palatable.

2019-09-27
15:00
First Steps of Planet Formation: Models & Observations
Paola Pinilla (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
In this new era of powerful telescopes such as ALMA, we are now able to study the birth of planets in disks around young stars, in more detail than ever before. New observations are revealing fascinating structures in protoplanetary disks that are transforming our understanding of the formation and evolution of planetary systems. In this colloquium, I will explain theoretical models of dust evolution in protoplanetary disks and I will compare these theoretical predictions with current multi-wavelength disk observations. This link is providing significant insights about how different physical conditions play a crucial role in the formation of the first planetesimals, and is extending our understanding of how initial conditions of protoplanetary disks are reflected in the large diversity of extrasolar systems observed up today.

2019-09-13
15:00
The rise and fall of cosmic star formation
Sarah Leslie (MPIA)
Königstuhl Kolloquium
MPIA lecture hall,
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Abstract
Galaxies grow on timescales of millions of years, so it is not an easy task to observe their changes directly. Instead, we collect observations for thousands of galaxies of different ages to infer how galaxy populations evolve over time. Dust is a small but important component of galaxies, obscuring on average 1/3 of the stellar light in local galaxies. I will discuss how this obscuration changes as a function of redshift using samples from the Sloan Digital Sky Survey (SDSS) and the Cosmic Evolution (COSMOS) survey. I will then present a promising way to circumvent uncertainties from dust attenuation by using observations at radio wavelengths. With dust-unbiased 3GHz observations of the COSMOS field, I have derived average star formation rates of galaxies from redshift 0.2 to 5, following the rise and fall of star formation activity in the Universe. I show the fraction of star formation activity occurring in galaxies of different stellar masses, morphological types, and environment. I find evidence that more massive galaxies live fast and die young, with the growth of bulges being an important aspect of this evolution.

2019-09-06
15:00
Modeling embedded star formation
Michael Kueffmeier (ITA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Stars are embedded in di?erent environments of Giant Molecular Clouds during their formation phase. Despite this fact, it is common practice to assume an isolated spherical core as the initial condition for models of individual star formation. To avoid the uncertainties of initial and boundary conditions, we use an alternative approach of zoom-in simulations to account for the environment in which protostars form. Our magnetohydrodynamical simulations show that the diversity in protostellar environments is reflected in the accretion process of protostars, as well as in the disk formation process. Regarding protostellar multiples our analysis suggests that companions initially form with wider separations of ~1000 au and afterwards migrate to smaller separations of ~100 au from the primary star. Against the background of observations of bridge-like structures such as seen for e.g. IRAS 16293-2422, we find that similar structures emerge as transient phenomena during protostellar multiple formation. To account for infall events of single stars at later times, we study how encounter events with gas condensations affects the properties of the star and the properties of its disk.

2019-08-30
15:00
Double stars are trouble stars: Close pairs in Gaia DR2, DR3, DR4
Uli Bastian (ZAH/ARI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
On the one hand, double stars are a nuisance for data reductions. On the other hand, they are scientifically interesting and important. After all, binaries probably constitute the majority of the overall stellar population. Thus they are crucial e.g. for our understanding of the formation of stars and planets in general. The Gaia mission sees, discovers, measures and parameterizes double stars - both optical pairs and physical binaries - in a surprising multitude of ways. Each of these ways poses an operational challenge as well as a scientific chance. Once fully exploited they will give a strongly revised picture of stellar binarity statistics. And they will remove all the disturbances caused by duplicity in the astrometric and photometric data of Gaia DR2. Gaia DR1 achieved an effective angular resolution (i.e.pair separations) of 2 arcsec, DR2 of 0.4 arcsec. But the actual optical resolution of the Gaia instrument is about 0.15 arcsec, and there are ways to detect and measure pairs down to the milli-arcsec level. All this can be done for hundreds of millions of stars, but it means a few more years of hard work by the Gaia data reduction consortium.

2019-08-02
15:00
The Industrial Revolution of Galactic archaeology
Sven Buder (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
How did the Milky Way form and evolve? Which processes shaped its structure at which times?
Stars as Galactic time capsules are our best tracers to answer these questions and in the recent years we have made revolutionary progress in observing their properties in large samples.
We have come to realise that our traditional picture of the Milky Way as a composite of three main stellar components (halo, disk, and bulge) is too simplistic - the stellar properties overlap and reveal great complexity. In order to confirm or reject formation scenarios of the Milky Way, we have to understand how the stellar properties come about and are interlinked.
I will outline the challenges that come with the collection of big data from stellar spectroscopic surveys, such as the 'Galactic Archaeology with HERMES' (GALAH) survey, and show which efficient and automated techniques we have developed to manage the very large data flow of stellar surveys.
In the course of my PhD, I have used the chemical information from GALAH together with dynamical information and stellar ages to analyse the Galactic disk in the solar neighborhood in order to disentangle the complex nature of the two populations of the disk. One of the big open questions is which role did accretion play in the formation of the disk populations? Could the recently (re-)discovered accreted halo stars of Gaia-Sausage/Gaia-Enceladus have caused the drastic change in the evolution of the disk?
During the KoCo I will guide you through the last 4 years of my journey in exploring the Milky Way and its chemodynamic information with the aim to shed light on the above mentioned questions.

2019-07-26
15:00
How (not) to select targets for a spectroscopic survey
David Hogg (NYU, MPIA)
Königstuhl Kolloquium
HdA auditorium,
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Abstract
The scientific capabilities of a spectroscopic survey depend on the spectroscopic data quality, on how the targets were selected, and on how well that selection can be quantitatively characterized. For many projects, the target selection and its characterization are the biggest sources of uncertainty for important results. There are many large spectroscopic programs in operation and starting in astrophysics. These range from cosmological large-scale structure mapping experiments, to large Galactic archaeology and stellar physics projects, to extreme-precision radial-velocity surveys for exoplanets, to follow-up of real-time events in streams from time-domain imaging surveys. In all of these cases, there will be important long-term scientific goals for these spectroscopic programs that depend on being able to make statistical inferences. For example, what is the distribution in phase space of stars with particular element abundances and ages? Or what is the occurrence rate of exoplanets of certain types at certain periods? In order for these questions to be answerable in the end, projects must be able to produce (at least approximate) selection functions. That requirement, in turn, puts constraints on the possible rules by which targets can be chosen for spectroscopic observation. I will discuss some parts of this, including some simple results?rules to live by?and some open questions.

2019-07-19
15:00
Stellar Radial Velocity Jitter: A model free analysis and an introduction to the RV SPY survey
Stefan Brems (LSW)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2019-07-19
15:00
The Formation and Growth of Supermassive Black Holes at Early Cosmic Epochs
Anna-Christina Eilers (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Quasars are the most luminous objects in the universe and can be observed at the earliest cosmic epochs, providing unique insights into the early phases of black hole, structure, and galaxy formation. Observations of these quasars demonstrate that they host supermassive black holes (SMBHs) at their center, already less than ~1 Gyr after the Big Bang. The formation and growth of these SMBHs in such short amounts of cosmic time is a crucial yet unanswered question in studies of quasar and galaxy evolution. An important piece of the puzzle is the lifetime of quasars ? the time that galaxies shine as active quasars ? but to date its value remains uncertain by several orders of magnitude. I will present a new method to obtain independent constraints on the lifetime of high redshift quasars, based on measurements of the sizes of the ionized regions around quasars, known as proximity zones. The sizes of these proximity zones are sensitive to the lifetime of the quasars, because the intergalactic gas has a finite response time to the quasars' radiation. Applying this method to a data set of high redshift quasar spectra at z>6, we discovered an unexpected population of very young quasars, indicating lifetimes of only ~10,000 years, which significantly challenges all current black hole formation theories. I will highlight the implications and tensions of such short quasar lifetimes on the SMBH formation paradigm, and discuss several potential modifications that could explain our results, for instance super-critical mass accretion rates, obscured quasar growth phases, or flickering quasar light curves. I will show potential ways to disentangle the various scenarios with future observations with the James Webb Space Telescope.

2019-07-12
15:00
Stellar Radial Velocity Jitter: A model free analysis and an introduction to the RV SPY survey
Stefan Brems (LSW)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Stars show various amount of radial velocity (RV) jitter due to varying
stellar activity levels. I will show that by systematically analyzing
archival RV data with the pooled variance technique, one can quantify
this jitter as a function of age and observational timescale (lag). The
results yield a very strong dependence on the stellar age, ranging from
over 800 m/s for 3 Myr old stars down to the instrumental precision of
about 1.5 m/s for several Gyr old stars. Furthermore, the lag influences
the intrinsic stellar RV variation by about a factor of two when
probing a few days instead of weeks or years.
These results can for example be used to plan surveys where the age is a
major selection criterion. Being such a survey targeting young stars, I
will present the observational strategy as well as first results from
ongoing Radial Velocity Survey for Planets around Young stars (RV SPY)
using the FEROS spectrograph at the MPG/ESO 2.2m telescope.

2019-07-05
15:00
The Milky Way Laboratory
Cara Battersby (Uni of Conneticut)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Our own Milky Way Galaxy is a powerful and relatively nearby laboratory in which to study the physical processes that occur throughout the Universe, from the organization of gas on galactic scales to the life cycle of gas and stars under varied environmental conditions. I will present a brief tour of our Milky Way Laboratory, including 1) the connection between long, filamentary molecular clouds and spiral structure, 2) statistical studies of high-mass star formation using surveys of our Galaxy's disk, and 3) how observing our extreme, turbulent Galactic Center (the Central Molecular Zone) can help us learn more about how gas is converted into stars during the peak epoch of cosmic star formation.

2019-06-28
15:00
MPIA space involvement
Oliver Krause & Knud Jahnke (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Space-based observatories have brought a tremendous progress to astronomy over the past decades. From inaccessible wavelength bands in the X-ray, UV or infrared, to much improved sensitivities from lower backgrounds, to diffraction limited imaging above the atmosphere - there are a number of key differences to ground-based observing facilities.

MPIA has been a long-standing contributor to space-based telescopes and their instrumentation, as well as scientific user of space-generated data. We will give an overview of five new upcoming space observatories with MPIA hardware contributions: JWST, Euclid, WFIRST, SPICA, and HabEx. We will present their construction status and timelines, as well as the opportunities for MPIA science exploitation.

2019-06-21
15:00
Characterization of Planetary Atmospheres
Karan Molaverdikhani (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Characterization of planetary atmospheres has always been a challenge. While the next generation of facilities, such as ELT, JWST, and ARIEL, will improve our understanding of planetary atmospheres, the number of well-characterized exoplanet atmospheres is expected to remain limited. Large-scale simulations assist us with this shortcoming by predicting the diversity of the planetary atmospheres, connecting the spare observational measurements, and by pointing toward the regions on the parameter space where a higher chance of the detection of planets with desired properties is expected. I will overview our current understanding of planetary atmospheres and will highlight the results of our hierarchical modelling of planetary atmospheres\; including our newly proposed classification scheme for irradiated gaseous planets and the Methane Valley.

2019-06-14
15:00
Gravitational instabilities: The fastest way to form planets
Hans Baehr (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The early stages of circumstellar disk evolution are likely influenced by the relatively large gas mass, driving gravitational perturbations that result in turbulence and disk fragmentation. Fragmentation of the disk produces dense gaseous objects with masses on the order of a few Jupiter masses an up, and preferentially occurs in the cool distant regions of the disk. This provides a possible formation channel for directly imaged planets which are difficult to account for otherwise. Unfortunately, despite filling in this niche of planet formation, several factors make gravitational instabilites a minor factor in the overall planet formation paradigm. I will discuss the viability of gravitational instabilities as a planet formation theory, including recent developments in both observation and theory. These developments perhaps point away from the formation of massive gaseous planets and towards the early concentration of solid material in the vein of traditional core accretion models, but within the first million years of the lifetime of the disk.

2019-06-07
15:00
New approaches to stellar ages: Chronostar for kinematic ages, and Gaia+interferometric orbits for evolutionary ages
: Michael Ireland (ANU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
One of the core goals of astrophysics is to determine the evolutionary history of stars, galaxies and the Universe. Unfortunately, there are few accurate determinations of ages of the Universe's constituents. I will describe new takes on two promising techniques for accurate stellar ages into the next decade. Firstly, I will describe the concept of ?traceback ages?, where stars from a common origin can have their ages determined by combining velocities with their distance from a common origin. This technique as largely failed so far, due to a myriad of reasons, including the rarity of unbound, compact clusters, and data where at least one kinematic axis has a large observational uncertainty. We have recently overcome these difficulties by combining the precision of Gaia data with Bayesian techniques and trace-forward of models in the Galactic potential, encompassed by the Chronostar code. We determine an age of beta Pic of 18.3+/-1.3 Myr, with an systematic uncertainty for individual members which is order the birth cluster crossing time of 12 Myr. I will describe the next steps for Chronostar, and where its limits are expected to lie. I will also briefly describe the problem of evolutionary ages for >1Gyr giant stars not part of a cluster. This is intimately connected to the controversy over the reported frequency of planets around ?retired A stars?. The combination of Gaia, long baseline interferometry and asteroseismology promises to significantly enhance our knowledge of these ages in the coming few years.

2019-05-24
15:00
Numerical experiments on star formation: mass functions and angular momenta
Lee Hartmann (UMich)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The initial mass function of stars - the number of stars N formed per interval of mass M - has long been known to be a power law, with d log N/d log M = ? = -1.3. Many explanations of this distribution have been advanced over the years, including fractal dimensions of star-forming molecular clouds and/or self-similar grouping of clouds. I will discuss simplified numerical simulations of star formation which show that gravitational accretion onto initial seed masses generates a power law mass distribution approaching ? ? -1 asymptotically, irrespective of complications of cloud structure. This mechanism can also explain the mass function of young star clusters, which also has a power law distribution with ? = -1. Finally, I will describe preliminary results concerning the origin of protostellar cloud angular momenta, including magnetic fields, with implications for the properties of protoplanetary disks that result from cloud collapse.

2019-05-17
15:00
Early-type galaxies: climbing to the top of the mass ladder
Eric Emsellem (ESO)
Königstuhl Kolloquium
MPIA lecture hall,
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Abstract
Nearby galaxies display a range of morphologies, sizes, masses, which are the results of a complex set of formation and evolution processes. In this talk, I will focus on early-type galaxies which contain about half of all the stars in our local Universe.
I will review our current knowledge of how they form, what are the most important mechanisms which shaped them, and illustrate how our understanding of these objects changed over the last decade via the use of simulations and integral-field spectroscopy. I will then focus on the most massive galaxies, and report on results from numerical simulations and an observational campaign conducted with the MUSE spectrograph, which led to some interesting surprises.

2019-05-10
15:00
What Processes Shape our Milky Way's Disk?
Hans-Walter Rix (MPIA)
Königstuhl Kolloquium
MPIA lecture hall,
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Abstract
It is often said that the Milky Way can serve as a 'model organism' to explore and understand the physical mechanism that shape galaxies from random initial fluctuations into the beautiful island universes we see today. This statement is true, but easily said and much harder to make a reality. Over the last years I have collaborated with a number of students, post-docs and visitors at MPIA combining spectral surveys and now Gaia to turn this Galactic Archeology mantra into astrophysical insights. In this talk I will synthesize some of this effort, focussing on two aspects of our Galaxy's main component, its disk:
what sets the overall radial profile of the disk, and what sets its vertical structure? The answers to both questions are linked to the question of how much dynamical memory loss our Galaxy has incurred -- despite its exceptionally quiescent history. I believe we are now considerably closer to understanding why disk galaxies look the way they do.

2019-05-03
15:00
Exocometary Science
Luca Matrà (CfA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Evidence for exocomets, icy bodies in extrasolar planetary systems, has rapidly increased over the past decade, giving rise to the budding field of exocometary science. Exocomets are detected through the gas and dust they release as they collide and grind down within their natal belts, or as they sublimate once scattered inwards to the regions closest to their host star. Most detections are in young, 10 to a few 100 Myr-old systems that are undergoing the final stages of terrestrial planet formation. This opens the exciting possibility to study exocomets at the epoch of volatile delivery to the inner regions of planetary systems.

In this talk, I will present the different lines of evidence for exocomets from UV to mm wavelengths. In particular, I will show how detection of molecular and atomic gas allows us to estimate molecular ice abundances and elemental abundances in young exocomets, enabling comparison with the Solar Nebula and Solar System comets. Finally, I will link the composition of exocometary belts to their origins in protoplanetary disks, discussing evidence for a preferential belt formation location which is dependent on the host star's luminosity.

2019-04-26
15:00
From dense cores to disk: Following the gas
Jaime Pineda (MPE)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
A detailed understanding of star-formation is important to establish the "micro-physics" involved in the galactic star-formation relations, and also to determine the initial condition for proto-planetary disks. One of the important steps in the star-formation process is the accumulation of material from the molecular cloud with supersonic turbulence into the dense cores, which have subsonic turbulence. The first direct observation of the transition between supersonic and subsonic turbulence in a nearby cloud provided the first direct constraints on this dissipation process. On the other hand, recent observations have shown that large protoplanetary disks in the early stages are relatively rare, and for those that are large, there is compelling evidence for asymmetries related to gravitational instabilities. However, little is known of the connection between the disks and the parental dense core.

In this talk, I will present some of our latest efforts on studying the dense core and molecular cloud connection, thanks to a large program at the Green Bank Telescope (~250hrs, PIs: Jaime Pineda and Rachel Friesen). This survey allows us to more accurately determine the dense core properties in a systematic fashion and across several clouds. Also, I will present interferometric observations of dense cores that will provide new insight into the core formation and the material transport down to the scales relevant for disk formation.

2019-04-12
15:00
The Brightest Stars in the Universe as Extragalactic Probes of Cosmic Abundances and Distances
Rolf-Peter Kudritzki (IFA,USM)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The determination of chemical composition and distance is crucial for investigating the formation and evolution of star-forming galaxies. Stellar absorption line studies based on quantitative spectroscopy provide an attractive alternative to the standard techniques using the strong emission lines of HII regions for chemical composition or stellar photometric methods for distances. I will introduce a number of newly developed methods
- multi-object spectroscopy of individual blue and red supergiant stars, the brightest
stars in the universe at visual and NIR wavelengths,
- NIR spectroscopy of super star clusters,
- optical spectroscopy of the integrated light of stellar populations in the disks of star
forming galaxies,
- the flux-weighted gravity luminosity relationship for distance determinations
and present results accumulated in the last two years. I will then discuss the scientific perspectives and potential of these methods for the use of future Extremely Large Telescopes (ELTs).

2019-04-05
15:00
The multi-phase ISM of radio galaxies: a spectroscopic study of ionised and warm gas
Francesco Santoro (MPIA)
Königstuhl Kolloquium
MPIA lecture hall,
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Abstract
Active galactic nuclei (AGN) are among the most powerful sources of energy in the universe. They usually resides at the centre of massive galaxies and their energy is originated by the accretion of material onto a supermassive black hole. AGN can inject a significant amount of energy in the interstellar medium (ISM) of their host galaxies in the form of radiation and/or jets of relativistic particles. The interaction between the energy emitted by an AGN and the material in the host galaxy is called 'AGN feedback' and, nowadays, is routinely included in cosmological simulations aimed at reproduction the observed properties of the current population of galaxies (e.g. the quenching of the star formation in massive galaxies).

In this talk I will address some of the open questions related to AGN feedback and to the mechanisms involved in the accretion of gas onto a supermassive black hole. This is has been done by studying the ISM of radio galaxies (i.e. AGN showing relativistic jets) spanning different evolutionary stages and by using different observational techniques, mainly in the optical and in the infrared band, to probe the warm ionised and warm molecular gas. In particular, I will focus on the effect that radio jets can have on the gas of the host galaxy and how this allows us to take a look at the many facets of the AGN feedback phenomenon.

2019-03-29
15:00
TBA
Paola Di Matteo (GEPI/Obs. de Paris)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Signature Speaker

2019-03-22
15:00
Paola Di Matteo (GEPI/Obs. de Paris)
: Signature Speaker
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2019-03-22
15:00
Paola Di Matteo (GEPI/Obs. de Paris)
: Signature Speaker
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2019-03-22
15:00
Probing the cold phase of the interstellar medium and star formation in nearby galaxies
Neven Tomicic (MPIA)
Königstuhl Kolloquium
MPIA lecture hall,
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Abstract
Properly measuring the spatial distribution of the star formation rate (SFR) in nearby galaxies helps us to understand the driving forces for the star formation in galaxies, and their effects on the interstellar medium (ISM). Additionally, it can lead to better understanding the physical factors that set the efficiency with which galaxies convert gas into stars (star formation efficiency\; SFE), and their role in galactic evolution. However, this is hindered by the uncertainties in estimating SFRs and calibrating the SFR prescriptions. Furthermore, variations in the star formation efficiency between and within galaxies are difficult to disentangle from uncertainties of their estimated SFRs. The uncertainties in estimating SFRs are caused by not properly measuring the attenuation of light, probing large spatial scales across nearby galaxies, or averaging over a large sample of galaxies.
To bypass these uncertainties, common SFR prescriptions are used, which also have large uncertainties and variations.

In this talk, I will show how we utilize optical integral field unit (IFU) observations of the nearby Andromeda galaxy, in order to properly measure the attenuation of light at high spatial resolution (100 pc), and thus properly estimate the SFRs and the SFR prescriptions. Moreover, by using the results of our optical IFU and sub-mm observations of the interacting galaxy NGC 2276, I will show how the early phase of galactic interaction affects the star formation efficiency of molecular gas across the interacting galaxy.

2019-03-22
09:45
The Milky Way as a dark matter lab
Jorge Penarrubia (ROE)
Königstuhl Kolloquium
MPIA lecture hall,

2019-03-21
09:45
A modern theoretical framework for the cosmic evolution of galactic emission lines
Michaela Hirschmann (U. Vienna, Dark Center)
Königstuhl Kolloquium
MPIA lecture hall,

2019-03-20
10:30
Numerical Structure and Galaxy Formation for Cosmological Insight
Annalisa Pillepich (MPIA)
Königstuhl Kolloquium
MPIA lecture hall (TBC),

2019-03-19
09:45
Intergalactic Signatures of Reionization and the Growth of the First Supermassive Black Holes
Frederick Davies (UC Santa Barbara)
Königstuhl Kolloquium
MPIA lecture hall,

2019-03-18
09:45
The Milky Way as a laboratory on galaxy formation and dark matter
Chervin Laporte (U. Victoria)
Königstuhl Kolloquium
MPIA lecture hall,

2019-03-15
15:00
"Milky Way dust in 3D: from local molecular clouds to the spiral arms"
Sara Rezaei Kh. (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract

Milky Way dust in 3D: from local molecular clouds to the spiral arms

Only a tiny fraction of the mass of the Galaxy is in dust, yet it plays important roles in different processes\; from the formation of stars and planets to the luminosity of the Galaxy. Attempts to map our Milky Way date back to the 18th century, but we are still struggling to find an accurate picture of our Galaxy as a result of our obscured view within the dusty disk. In this talk, I will give you a general introduction to dust and extinction, followed by a summary of the improvements in 3D dust extinction mapping. I will then introduce our new technique in mapping the 3D distribution of dust in the Milky Way using the Gaussian process that allows capturing arbitrary structures and results in smooth maps without artefacts typically seen in most other methods. I will show our results based mainly on data from Gaia and APOGEE for the local molecular clouds as well as the Galactic disk, where we unveil the distribution of the spiral arms of the Milky Way in dust.

2019-03-08
15:00
Science with VLTI+GRAVITY
Woflfgang Brandner (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
GRAVITY is a 4-telescope beam combiner for ESO's Very Large Telescope Interferometer (VLTI), working in the K-band. While the instrument design has been optimized for high-precision observations of the Milky Way's central supermassive black hole Sgr A* and its immediate environment, the unique sensitivity of VLTI+GRAVITY enable a large range of science applications.

In this talk, I will briefly describe the main capabilities and technological innovations of GRAVITY, which includes the four CIAO (one for each of the 8m-Unit Telescopes) infrared adaptive optics systems provided by MPIA, followed by a concise overview of science results obtained during GRAVITY commissioning and the first 1.5 years of regular science operations at the VLTI. The science topics range from the atmosphere of the exoplanet HR 8799e over properties of disks and outflows in the central AU of Young Stellar Objects, multiplicity of stars in the center of the Orion Nebula Cluster, resolution of microlensed images, spectral-imaging of the close environment of Eta Carinae, and observations of Galactic X-ray binaries, to the study of relativistic effects in the Galactic Center, and a direct measurement of the mass of the supermassive blackhole in the center of the quasar 3C 273.

2019-03-01
15:00
TBA
: Sara Rezaei Kh. (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2019-03-01
15:00
TBA
Marcel Neeleman (MPIA)
Königstuhl Kolloquium
MPIA lecture hall,

2019-02-22
15:00
Stellar populations in the densest stellar systems in the Universe
Nikolay Kacharov (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
In this talk I will introduce some of the open questions in the field of globular clusters and nuclear star clusters. As one part of the colloquium, I will talk about the multiple populations phenomenon in globular clusters and focus on our recent discoveries in intermediate age clusters in the Magellanic Clouds. The second part will be dedicated to the much more extended star formation histories in nuclear star clusters. I will discuss our discrete IFU spectroscopic observations of the nucleus of the tidally disrupted Sgr dSph galaxy - the massive globular cluster M54, and also integrated light spectroscopy in the nuclei of yet undisturbed nearby galaxies. I will explore and discuss possible theories for the formation of these very dense objects based on our observations.

2019-02-15
15:00
The Cosmic Evolution of Cold Molecular Gas since Redshift 6 from A3COSMOS
Daizhong Liu (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Determining the cosmic evolution of cold molecular gas in galaxies is fundamental for our understanding of galaxy evolution. However, obtaining such measurements for large samples of galaxies at z~1--6 remains challenging even in the era of ALMA. Recent studies of the cosmic gas evolution focus on redshifts below z=3 reporting conflicting results, and cosmological simulations still struggle to fit the observations. As (sub-)millimeter dust continuum has now been established as a reliable tracer of the cold gas, and it can be much more efficiently observed than line tracers (e.g. CO), we have started a concerted effort to automatically mine the public ALMA archive for the COSMOS field (A3COSMOS). A3COSMOS provides (sub-)millimeter detections and subsequent galaxy properties in a coherent, systematic way that allows us to quantify systematic biases in using dust continuum. Our database currently includes about 2000 ALMA images covering 280 sq. arcmin with over 1500 ALMA detections based on well-characterized statistics. Using rich ancillary data available we identify ~1000 galaxies with bona-fide properties lying at z~1--6. We combine this unique catalog of cold gas measurements with more than 500 local (z~0) and high-redshift (z<3) galaxies with CO and/or dust continuum detections in the literature to explore the correlations between gas mass fraction, molecular gas depletion time, redshift, stellar mass and star formation rate. Our analysis reveals a linear evolution of the gas fraction with cosmic time, in line with the evolution of the ?galaxy main sequence?. This evolution further implies a cosmic molecular gas density evolution consistent with previous works at z<1-3, but higher by a moderate factor at z>5--6 as predicted by cosmological simulations. As ALMA accumulates more observations in the future, the cold molecular gas evolution at z>5--6 will eventually be constrained by A3COSMOS.

2019-02-08
15:00
Dust Spreading in Debris Discs: Do Small Grains Cling on to Their Birth Environment?
Nicole Pawellek (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Debris discs are dusty belts of planetesimals around main-sequence stars, similar to comets and asteroids in the solar system. The planetesimals themselves cannot be observed directly, yet they produce detectable dust in mutual collisions. Observing this debris dust, we can try to infer properties of invisible planetesimals. Here we address the question of what is the best way to measure the location and extent of outer planetesimal belts, i.e., ''Kuiper belts'' that encompass extrasolar planetary systems. A standard method is using resolved images at millimetre wavelengths, which reveal dust grains of comparable sizes. This is because smaller dust particles seen in the infrared or optical are subject to a large array of non-gravitational forces that drag them away from their birth places, and so may not closely trace the parent bodies. In this study, we examine whether imaging of debris discs at shorter, far- or even mid-infrared, wavelengths might enable determining the spatial location of the exo-Kuiper belts with sufficient accuracy. We find that around M-type stars the dust best visible in the mid-infrared is efficiently displaced inward from their birth location by stellar winds, causing the discs to look more compact in the mid-infrared images than they actually are. However, around A-type stars, where the majority of debris discs is found, and even around G-type stars, discs are still the brightest at the location of the birth ring at mid-infrared wavelengths. Thus, sensitive infrared facilities with good angular resolution, such as MIRI on the James Webb Space Telescope, will enable tracing exo-Kuiper belts in nearby debris disc systems.

2019-02-01
15:00
Stellar Interiors as seen from Asteroseismology
Conny Aerts (U. Leuven)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The space age of asteroseismology brought tremendous progress in the
observational probing of stellar interiors. In this seminar, we first explain
for the non expert how asteroseismology allows to deduce the interior physics of
stars at a level that is impossible to reach in any other way. We summarise the
great asset of asteroseismic sizing, weighing, and ageing of low-mass stars,
with applications to exoplanetary science and galactic archeology. Further, we
focus on the capability to derive the interior rotation properties of various
types of stars and discuss the implications for the theory of angular momentum
transport. We also touch upon recent findings on chemical mixing in the deep
interior of single and binary stars with a convective core. We end the talk by
highlighting the major opportunities from combining space asteroseismology and
astrometry with ground-based spectroscopy of large ensembles of stars in the
Milky Way and in the Magellanic Clouds.

2019-01-25
15:00
Giant Molecular Filaments studied in different gas tracers
Yuan Wang (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Observations show that large (~100~pc) and massive (~10^5 Msun) filaments, known as giant molecular filaments (GMFs), may be linked to galactic dynamics and trace the gravitational mid-plane in the Milky Way (MW). They are the largest coherent gas structures and a central building block of the Milky Way. Yet our understanding of GMFs is still poor, limited to estimates of their occurrence, gas masses and lengths. In this talk, I will present our studies of two GMFs (GMF38a and GMF54), which are observed with different gas tracers (atomic and molecular). We studied the cold neutral media of atomic hydrogen via HI self-absorption towards the ~200pc long filament GMF38a, and compared the kinematics and column density distribution of the atomic hydrogen to the molecular gas (CO). The column density probability density functions (N-PDFs) show that the atomic gas is dominated by turbulent motions, whereas the N-PDF of the molecular gas shows a power-law tail that indicates gravitational collapse. We further mapped the dense gas of GMF54 (~45pc) with the IRAM 30m telescope, covering the common dense gas tracers HCN, HNC, HCO+ and their 13C isotopologues, as well as the cold dense gas tracer N2H+. Combining the complementary 13CO data, we studied and compared the kinematics and the density distribution of GMFs over an order of magnitude in density.

2019-01-18
15:00
Star Formation and Galactic Environment
Eva Schinnerer (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
High angular resolution observations of nearby galaxies allow us to sample the star formation process in different galactic environments.This provides insights on the importance and role of galactic components such as bulges, stellar bars, spiral arms and active galactic nuclei (AGN) in the conversion of cold (molecular) gas into stars. New instruments can now regularly image with high quality and sensitivity large field-of-views
at the scale of individual star-forming units, namely Giant Molecular Clouds (GMCs) and HII region (complexes): ALMA is fundamental for imaging of the molecular gas properties in the star-forming disks, while the optical Integral Field Unit MUSE on the VLT is providing detailed information on the ionised gas and stellar population. I will highlight recent progress in the field and present new results from the Physics at High Angular resolution in Nearby GalaxieS (PHANGS) survey that studies a representative sample of nearby massive, normal star-forming galaxies.

2019-01-11
15:00
The Disk Substructures at High Angular Resolution Project (DSHARP)
Kees Dullemond (ITA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Abstract: DSHARP is an ALMA Large Programme aimed at obtaining high-resolution (beam ~ 30 milliarcsec) maps of 20 protoplanetary disks in band 6 (1.3 mm) in the continuum. The data were released about a month ago, along with a first set of papers. I will give an overview of the data and some of the gems hidden in them. I will then focus on the theoretical interpretation that the DSHARP team has done, and many of the still open questions that need to be addressed in the coming months.

2018-12-14
15:00
TBA
Karin Lind (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBA

2018-12-14
15:00
Lithium in the Galaxy: To Be or not to Be
Karin Lind (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The astronomical community's interest in Li continues to be vastly disproportional to its small abundance. The Li content of stars in the Galaxy links together several different research fields\; from cosmology and Big Bang nucleosynthesis, to cosmic ray spallation in the interstellar medium, to mixing processes in stellar interiors, and even the presence of exoplanets. I will describe the intricate abundance patterns found for stars in different evolutionary phases and how the fragile nature of this light element makes it an excellent diagnostic tool for late-type stellar evolution all they way from the pre-main sequence to the tip of the asymptotic giant branch. I will further discuss some famous problems related to Li production and depletion and potential solutions in the light of improved models of stars and their spectra.

2018-12-07
15:00
TBD
HHSF18
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2018-12-07
15:00
The Square Kilometer Array
Tyler Bourke (SKAO)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The Square Kilometre Array (SKA) is a global effort to build the World's largest radio telescopes, which will transform our understanding in many areas of astrophysics, including the history of our Universe and the emergence of the first stars and galaxies\; the merger of super-massive black-holes and their release of gravitational waves, as tests of General Relativity\; the enigmatic powerful bursts of radio emission (Fast Radio Bursts) whose origin and nature remain controversial\; the formation of planets and search for extraterrestrial life\; and many other areas of great interest to astronomers worldwide.

The past few years have seen great progress toward the realization of the SKA, with construction of Phase 1 (SKA1) to start in 2020 and science operations anticipated to begin in 2026. In this presentation I will provide a status update on SKA activities, with a focus on the science it will enable and the progress toward construction.

2018-11-30
15:00
Patzer Colloquium
TBA (TBA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2018-11-30
15:00
Three award winners
Patzer Colloquium (MPIA+ZAH)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2018-11-23
15:00
TBD
Bertram Bitsch (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2018-11-23
15:00
Planet formation in evolving protoplanetary discs
Bertram Bitsch (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Observations of exoplanets have revealed a complex diversity in planetary systems regarding their masses, orbital configurations and number of planets. For example it has been shown that super-Earth planets are the most common planets in our galaxy even though we have no super-Earth in our own solar systems and that these planets are mostly in multiple systems. Hot Jupiters, on the other hand, are easy to detect, but are actually very rare objects. In addition new observations give indications about the chemical compositions of these planets. All these constraints have to be matched by theories of planet formation.

The formation of planetary cores of several Earth masses can be greatly accelerated by accreting objects of mm-cm size, so called pebbles. When the planetary cores have reached masses around 10 Earth masses, they can start to accrete gas from the protoplanetary disc and eventually form gas giants, like Jupiter and Saturn in our own solar system. During their formation, the planetary cores interact gravitationally with the disc and migrate through it. At the same time the protoplanetary disc evolves so that its temperature decreases, resulting in an inward movement of the water ice line. Previous simulations have also mostly followed the evolution of single planets, where multi-body dynamics have been ignored.

I will present here our new framework of planet formation that features a complex interplay between N-body dynamics, pebble accretion, planet migration, disc evolution and planetary instabilities after the gas disc phase. I will highlight the results of our new simulations and point to open questions that need to be answered in order to constrain planet formation theories even further.

2018-11-16
15:00
TBD
Rowan Smith (University of Manchester)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2018-11-16
15:00
Filaments all the way down: Simulating molecular gas in the Milky Way
Rowan Smith (University of Manchester)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The process of star formation and galaxy evolution are inseparably linked. Stars feed back energy and momentum into the ISM, but galactic scale forces will help determine where dense star-forming molecular clouds can form. Previously star formation was simulated only in isolation, and galaxy scale models did not resolve star forming clouds, however recent simulation efforts have begun to unite these important physical processes. Observations have also shown us that molecular clouds are far from the abstracted collapsing spherical clouds or periodic turbulent boxes used to model them previously. Instead many clouds take the form of long filaments with extremely coherent velocities.

In this talk I present simulations exploring the morphology and star formation in filamentary molecular clouds from spiral galaxy simulations with AREPO. The clouds are resolved down to sub-parsec scales in the original simulation meaning, uniquely, that both galactic-scale forces and internal cloud substructure can be studied at the same time. The simulations include supernovae feedback, self-gravity, time-dependent chemistry and sinks particles to represent sites of star formation. This allows us to study the evolution of the CNM, where gas will be bright in CII or CO emission, and where there will be CO dark gas.

Using this dataset we can extract filamentary clouds and compare their lengths and widths against observations of arm and inter-arm filaments observed in our Galaxy. Within our simulated clouds we identify networks of dense filaments connecting star forming gas cores. Previous analysis of such networks of filaments in isolated turbulent molecular cloud cores. has shown that the mass flows along filaments play a key role in building up a stellar initial mass function, and in growing massive stars.

2018-11-09
15:00
The base material of terrestrial planets - investigating the dust in the inner region of protoplanetary disks
Lucia Klarmann (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The inner regions of protoplanetary disks are where terrestrial planets and super-Earths form and/or migrate to. The small spatial extend of this region makes direct observations difficult. But interferometric observations and dust modeling can put constraints on the base material of terrestrial planet formation.

We self-consisently calculate the expected rim structure for a wide range of possible dust compositions. Synthetic observations of these radiative transfer models show that the rim position can be well constrained using NIR interferometry. Comparing our rim positions with observations from Lazareff+17, we find that the observed positions can be explained by a power law grain size distribution, but also the presence of highly refractory grains.

Motivated by the low carbon fraction in the Earth, we investigate how to sustain a low fraction of refractory carbon in the inner disk. We find that radial dust transport in the disk must be significantly reduced during parent body formation, possibly by a quickly formed giant planet core. Otherwise grains from the outer disk region will replenish refractory carbon very efficiently within the grain drift timescale.

2018-10-26
15:00
TBD
Mario Flock (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2018-10-26
15:00
The Inner Regions of Protoplanetary Disks: 3D Radiation Magneto-Hydrodynamical Models
Mario Flock (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Many planets orbit within an AU of their stars, raising questions about their origins. Particularly puzzling are the planets found near the silicate sublimation front. We investigate conditions near the front in the protostellar disk around a young intermediate-mass star, using the first global 3D radiation non-ideal MHD simulations in this context.

The results show magnetorotational turbulence around the sublimation front at 0.5 AU. Beyond 0.8 AU is the dead zone, cooler than 1000 K and with turbulence orders of magnitude weaker. A local pressure maximum just inside the dead zone concentrates solid particles, allowing for efficient growth. Over many orbits, a vortex develops at the dead zone's inner edge, increasing the disk's thickness locally by around 10%.

We synthetically observe the results using Monte Carlo transfer calculations, finding the sublimation front is bright in the near-infrared. The models with vertical magnetic flux develop extended, magnetically-supported atmospheres that reprocess extra starlight, raising the near infrared flux 20%. The vortex throws a non-axisymmetric shadow on the outer disk.

Radiation-MHD models of the kind we demonstrate open a new window for investigating protoplanetary disks' central regions. They are ideally suited for exploring young planets' formation environment, interactions with the disk, and orbital migration, in order to understand the origins of the close-in exoplanets.

2018-10-19
15:00
TBD
Michael Rugel (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
TBD

2018-10-19
15:00
OH abundance and feedback from star clusters with the THOR survey
Michael Rugel (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
In this colloquium, I present characterizations of molecular cloud properties with the THOR survey (The HI, OH and Radio Recombination Line (RRL) survey of the Milky Way). We analyze OH absorption at 18 cm within THOR and follow-up observations. We derive the abundance with respect to molecular hydrogen and the total number of hydrogen nuclei: 1) We find a decreasing OH abundance with increasing column density of molecular hydrogen. 2) Due to significant column densities of atomic hydrogen at low OH column density, the OH abundance with respect to the column density of hydrogen nuclei is approximately constant. 3) We detect OH components which are associated with gas that is not predominantly molecular or even CO-dark. We conclude that OH is a potential tracer for diffuse gas.
Regarding the impact of star clusters on molecular clouds, we detect signatures of feedback in RRL emission in the star forming region W49A. A comparison to the WARPFIELD models (one-dimensional models of feedback-driven shells) indicates that feedback is not yet strong enough to disperse its molecular cloud and that the shell is either in process of re-collapsing to initiate a new event of star formation or has already re-collapsed. This suggests that at least parts of the star formation in W49A is regulated by feedback.

2018-10-12
15:00
TBD
Fei Yan (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2018-10-12
15:00
Transit spectroscopy of exoplanet atmospheres
Fei Yan (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
With almost 4000 exoplanets been discovered, characterizing their atmospheres becomes a rapidly expanding branch in exoplanet research. In this talk, I will focus on transit spectroscopy ? the most commonly used method for atmosphere observations. This method has been successfully applied to discover various chemical species (e.g. water, carbon monoxide, sodium) as well as to characterize psychical conditions like temperature profile and wind. I will present results of our transit observations with CARMENES and MODS/LBT spectrographs, including probing the atmosphere of the hottest exoplanet - KELT-9b. In addition, I will also talk about how the variation of stellar line profiles during transit will affect exoplanet atmosphere observations.

2018-10-05
15:00
TBA
PSF signature speaker Sarah Hörst (JHU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2018-10-05
15:00
Exploring Planetary Atmospheres in a Lab
PSF signature speaker Sarah Hörst (JHU) : Planets in a Bottle
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
From exoplanets, with their surprising lack of spectral features, to Titan and its characteristic haze layer, numerous planetary atmospheres may possess photochemically produced particles of "haze". With few exceptions, we lack strong observational constraints (in situ or remote sensing) on the size, shape, density, and composition of these particles. Photochemical models, which can generally explain the observed abundances of smaller, gas phase molecules, are not well suited for investigations of much larger, solid phase particles. Laboratory investigations of haze formation in planetary atmospheres therefore play a key role in improving our understanding of the formation and composition of haze particles. I will discuss a series of experiments aimed at improving our understanding of the physical and chemical properties of planetary atmospheric hazes on Titan, Pluto, super-Earths, and mini-Neptunes.

2018-09-28
15:00
The Intricate Role of Cold Gas and Dust in Galaxy Evolution at Early Cosmic Epochs
Dominik Riechers (Cornell, MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Great progress has been made over the past two decades in constraining
the star formation history of the universe, but our understanding of
how cosmic star formation is fuelled by cold gas at high redshift is
currently informed primarily by specific, and potentially biased
samples of galaxies. To overcome these limitations, we have carried
out the CO Luminosity Density at High Redshift (COLDz) survey, a large
blind volume search for cold molecular gas in galaxies at redshifts
2-3 and 5-7 with the Karl G. Jansky Very Large Array (VLA). The
resulting measurement of the "cold gas history of the universe" near
the peak epoch of cosmic star formation and in the first billion years
of cosmic time provides important information on the fuelling
mechanisms that drive cosmic star formation. Surveys like COLDz set
the necessary broader context for targeted in-depth studies of the
physical properties of star formation in different galaxy populations
back to the earliest epochs with the Atacama Large sub/Millimeter
Array (ALMA). Such studies fundamentally enhance our picture of early
galaxy evolution by providing a better understanding of the stellar
mass buildup, and they are a critical pathfinder toward galaxy surveys
in the early universe with upcoming large facilities, in particular
the next generation Very Large Array (ngVLA).

2018-09-28
15:00
Evolution of Gas Content Through Cosmic History
Fabian Walter (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The temporal evolution of the cosmic star formation rate density is now well established out to high redshift. This star formation rate density shows a clear peak at z~1-2 that is about one order of magnitude higher than today. The cause for this behavior must be driven by the properties of the underlying reservoir of molecular gas, the fuel for star formation galaxies. The last decade has seen dramatic progress in quantifying the molecular gas content in galaxies through cosmic times, through various observational camapigns. I will summarize our current view of the molecular gas content in distant galaxies. This will include some of the recent results emerging from ASPECS: The ALMA SPECtroscopic Survey in the Hubble Ultra-Deep Field (UDF). This ALMA large program provides a census of molecular gas in high-redshift galaxies through full frequency scans at approximately uniform line sensitivity. The resulting cosmic molecular gas density as a function of redshift shows a factor 3-10 decrease from z=2 to z=0. The cosmic star formation history therefore appears to be at least partly driven by the increased availability of molecular gas reservoirs at the peak of cosmic star formation (z~2).

2018-09-21
15:00
The World Beyond the Snow Line: Microlensing Comes of Age
Andy Gould (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Microlensing is orthogonal to all other planet-search techniques. First, its sensitivity to planets peaks just beyond the snowline, where planets are thought to be most common. Second, it is roughly equally sensitive to planets around all stars, independent of their luminosity, and even to planets that have no host. Third, it is roughly equally sensitive to planets at a range of distances from 1 to 8 kpc. These features potentially enable microlensing to cast a radically different light on planetary demographics. I discuss how the 10-fold increase in microlensing data provided by the Korea Microlensing Telescope Network (KMTNet) and "microlens parallax" observations with the Spitzer Space Telescope are rapidly unleashing this potential.

2018-09-21
15:00
The World Beyond the Snow Line: Microlensing Comes of Age
Andy Gould (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Microlensing is orthogonal to all other planet-search techniques. First, its sensitivity to planets peaks just beyond the snowline, where planets are thought to be most common. Second, it is roughly equally sensitive to planets around all stars, independent of their luminosity, and even to planets that have no host. Third, it is roughly equally sensitive to planets at a range of distances from 1 to 8 kpc. These features potentially enable microlensing to cast a radically different light on planetary demographics. I discuss how the 10-fold increase in microlensing data provided by the Korea Microlensing Telescope Network (KMTNet) and "microlens parallax" observations with the Spitzer Space Telescope are rapidly unleashing this potential.

2018-09-14
15:00
Quantifying and understanding variations in star formation
Sami Dib (NBI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Star formation is a multi-physics, multi-scale process. The multiplicity of physical processes and scales can generate a significant amount of scatter in the outcome of star formation, in particular in terms of key quantities such as the stellar initial mass function (IMF), the star formation rate (SFR), and the star formation efficiency (SFE). By analyzing large data sets that are becoming increasingly available, one can now assess whether variations do actually exist, quantify them, and attempt to explain them via a comparison with (a range of) theoretical models. I will illustrate this by presenting examples related to the IMF in young Galactic stellar clusters and to the star formation scaling relations in nearby galaxies. I will show that current data argues against a universal IMF in Galactic stellar clusters. I will also argue that the star formation scaling relations on galactic scales should include a description of the role of several other physical quantities, instead of being understood in terms of a mere dependence of the SFR on the density of the star forming gas.

2018-09-14
15:00
Quantifying and understanding variations in star formation
Sami Dib (NBI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Star formation is a multi-physics, multi-scale process. The multiplicity of physical processes and scales can generate a significant amount of scatter in the outcome of star formation, in particular in terms of key quantities such as the stellar initial mass function (IMF), the star formation rate (SFR), and the star formation efficiency (SFE). By analyzing large data sets that are becoming increasingly available, one can now assess whether variations do actually exist, quantify them, and attempt to explain them via a comparison with (a range of) theoretical models. I will illustrate this by presenting examples related to the IMF in young Galactic stellar clusters and to the star formation scaling relations in nearby galaxies. I will show that current data argues against a universal IMF in Galactic stellar clusters. I will also argue that the star formation scaling relations on galactic scales should include a description of the role of several other physical quantities, instead of being understood in terms of a mere dependence of the SFR on the density of the star forming gas.

2018-09-07
15:00
Magnetic Fields ? Polarization ? Disks
Gesa Bertrang (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Magnetic fields are predicted to be an important factor for a wide range of physical processes in protoplanetary disks. In the classical picture, (sub-)mm continuum polarization is the tracer for magnetic fields in disks. Aspherical dust grains, whose thermal emission is intrinsically polarized, get aligned by the magnetic field due to radiative torques. In recent years, however, this picture has been challenged. New theoretical studies show that (sub-)mm continuum polarization can also be created by scattering of the thermal dust emission or arise from aspherical grains which are aligned by the radiation field rather than the magnetic field. These three mechanisms trace fundamentally different physics in protoplanetary disks, yet, their polarization predictions are not clearly distinguishable. In this talk, I will highlight the role of magnetic fields in protoplanetary disks, present already achieved (indirect) observational constraints, and give an outlook on how to disentangle the sources of continuum polarimetry with ALMA by applying spectro-polarimetry.

2018-09-07
15:00
Magnetic Fields ? Polarization ? Disks
Gesa Bertrang (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Magnetic fields are predicted to be an important factor for a wide range of physical processes in protoplanetary disks. In the classical picture, (sub-)mm continuum polarization is the tracer for magnetic fields in disks. Aspherical dust grains, whose thermal emission is intrinsically polarized, get aligned by the magnetic field due to radiative torques. In recent years, however, this picture has been challenged. New theoretical studies show that (sub-)mm continuum polarization can also be created by scattering of the thermal dust emission or arise from aspherical grains which are aligned by the radiation field rather than the magnetic field. These three mechanisms trace fundamentally different physics in protoplanetary disks, yet, their polarization predictions are not clearly distinguishable. In this talk, I will highlight the role of magnetic fields in protoplanetary disks, present already achieved (indirect) observational constraints, and give an outlook on how to disentangle the sources of continuum polarimetry with ALMA by applying spectro-polarimetry.

2018-08-10
15:00
Fitting a model to data, 2018 edition
David Hogg (NYU, MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
I use examples from the Gaia Mission to illustrate ideas behind the theory and best practices for fitting a model to data. I will address (a) accounting for noisy data and selection effects, (b) dealing with outliers, and (c) model selection and deciding among models. I use very simple models (like straight lines!) and Gaia data for my examples, but the rules I give ? which are designed to minimize the loss of information ? are applicable at all model complexities and in all domains.

2018-08-10
15:00
Fitting a model to data, 2018 edition
David Hogg (NYU, MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
I use examples from the Gaia Mission to illustrate ideas behind the theory and best practices for fitting a model to data. I will address (a) accounting for noisy data and selection effects, (b) dealing with outliers, and (c) model selection and deciding among models. I use very simple models (like straight lines!) and Gaia data for my examples, but the rules I give ? which are designed to minimize the loss of information ? are applicable at all model complexities and in all domains.

2018-08-03
15:00
Mind the gap: swimming the channels between islands of popular star formation research
Joe Mottram (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Like most sub-fields, star formation research has it's popular topics for research. Current examples include searching for structure in disks around low or high-mass protostars, and studying filaments in molecular clouds. I will present research from three projects, each of which aimed to make progress on our broader understanding of the star formation process and ISM lifecycle by exploring the space between these popular islands of research. First, I will present studies of thermal H2O and CO transitions observed towards a sample of low, intermediate and high-mass young stellar objects in order to explore the differences and similarities between low and high-mass protostars. This project ultimately led to a surprising alternative explanation for the emission in such transitions from external galaxies. Second, I will show observational studies of ionised pillars with CARMA, ALMA and MUSE, and how these are helping to constrain models of how these iconic structures are formed. Finally, I will discuss part of my work here at the MPIA combining single-dish and interferometric data to link sites of high-mass star formation with their surroundings. Taken together, these projects reveal the value of striking our into new territory by exploring the space between our islands of knowledge.

2018-08-03
15:00
Mind the gap: swimming the channels between islands of popular star formation research
Joe Mottram (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Like most sub-fields, star formation research has it's popular topics for research. Current examples include searching for structure in disks around low or high-mass protostars, and studying filaments in molecular clouds. I will present research from three projects, each of which aimed to make progress on our broader understanding of the star formation process and ISM lifecycle by exploring the space between these popular islands of research. First, I will present studies of thermal H2O and CO transitions observed towards a sample of low, intermediate and high-mass young stellar objects in order to explore the differences and similarities between low and high-mass protostars. This project ultimately led to a surprising alternative explanation for the emission in such transitions from external galaxies. Second, I will show observational studies of ionised pillars with CARMA, ALMA and MUSE, and how these are helping to constrain models of how these iconic structures are formed. Finally, I will discuss part of my work here at the MPIA combining single-dish and interferometric data to link sites of high-mass star formation with their surroundings. Taken together, these projects reveal the value of striking our into new territory by exploring the space between our islands of knowledge.

2018-07-27
15:00
Reconstruction of the Milky Way with tidal streams
Ana Bonaca (CfA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The arduous quest of reconstructing the distribution of matter in the Galaxy has been reinvigorated in the months following the second data release from the Gaia mission. Studies of cold stellar streams -- remnants of tidally disrupted globular clusters which trace the underlying gravitational potential -- received a particular boost thanks to the Gaia proper motions. Employing the Fisher information approach, we show that the mean track of a stream's 6D positions and velocities intrinsically constrains the total enclosed mass at the stream's current position. Furthermore, Gaia's view of the longest cold stream, GD-1, uncovered significant density variations along the stream and stars offset from the main track -- likely signatures of a perturbed past. Using multiple streams to measure the enclosed mass in different regions of the Milky Way, and GD-1 to test for the presence of low-mass dark matter subhalos, we should produce a 3D map of the Milky Way halo that can distinguish between competing cosmological models.

2018-07-27
15:00
Reconstruction of the Milky Way with tidal streams
Ana Bonaca (CfA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The arduous quest of reconstructing the distribution of matter in the Galaxy has been reinvigorated in the months following the second data release from the Gaia mission. Studies of cold stellar streams -- remnants of tidally disrupted globular clusters which trace the underlying gravitational potential -- received a particular boost thanks to the Gaia proper motions. Employing the Fisher information approach, we show that the mean track of a stream's 6D positions and velocities intrinsically constrains the total enclosed mass at the stream's current position. Furthermore, Gaia's view of the longest cold stream, GD-1, uncovered significant density variations along the stream and stars offset from the main track -- likely signatures of a perturbed past. Using multiple streams to measure the enclosed mass in different regions of the Milky Way, and GD-1 to test for the presence of low-mass dark matter subhalos, we should produce a 3D map of the Milky Way halo that can distinguish between competing cosmological models.

2018-07-20
15:00
Science with the Stratospheric Observatory for Infrared Astronomy (Sofia)
Maja Kazmierczak-Barthel (DSI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The infrared is a key part of the electromagnetic spectrum for studying star formation and evolution, galaxies, planets, and the interstellar medium. As most infrared wavelengths are absorbed by the water vapor of our planet's atmosphere, except for a few narrow spectral windows, astronomical infrared observations have been limited to space-, balloon-, or aircraft-observatories. SOFIA is the last remaining observatory from a truly "Golden Age" for Mid- and Far-Infrared Astronomy, that included space missions like IRAS, ISO, Spitzer, and Herschel. At least for another decade or two SOFIA will be the only observatory that can regularly access the Mid-and Far-Infrared sky.

SOFIA consists of a 2.7m telescope (effective 2.5m), that is lifted by a heavily modified Boeing 747-SP into the stratosphere above more than 99% of the atmosphere's water vapor. A full complement of instruments provides imaging, spectroscopic, and polarimetric capabilities, to follow up and extend many discoveries of past infrared space missions that ended due to a limited supply of cryogen. In addition, it provides for more progress, as very new state of the art instrumentation can be used, returned to the lab, and further improved. The mobility of the facility gives rise to even more observational opportunities like stellar occultations and other targets of opportunity.

The presentation will give an overview over the capabilities of the observatory, including a few illustrative scientific applications. We will discuss the wavelength coverage, sensitivities, and observing modes, as well as limitations that arise from the specifics of an observational platform on-board of an aircraft. Particular emphasis will be given to the recently released "Cycle 7 Call for Proposals", the specific tools necessary for proposal generation, and how to successfully compete for observing time on SOFIA.

2018-07-20
15:00
Science with the Stratospheric Observatory for Infrared Astronomy (Sofia)
Maja Kazmierczak-Barthel (DSI)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
The infrared is a key part of the electromagnetic spectrum for studying star formation and evolution, galaxies, planets, and the interstellar medium. As most infrared wavelengths are absorbed by the water vapor of our planet's atmosphere, except for a few narrow spectral windows, astronomical infrared observations have been limited to space-, balloon-, or aircraft-observatories. SOFIA is the last remaining observatory from a truly "Golden Age" for Mid- and Far-Infrared Astronomy, that included space missions like IRAS, ISO, Spitzer, and Herschel. At least for another decade or two SOFIA will be the only observatory that can regularly access the Mid-and Far-Infrared sky.

SOFIA consists of a 2.7m telescope (effective 2.5m), that is lifted by a heavily modified Boeing 747-SP into the stratosphere above more than 99% of the atmosphere's water vapor. A full complement of instruments provides imaging, spectroscopic, and polarimetric capabilities, to follow up and extend many discoveries of past infrared space missions that ended due to a limited supply of cryogen. In addition, it provides for more progress, as very new state of the art instrumentation can be used, returned to the lab, and further improved. The mobility of the facility gives rise to even more observational opportunities like stellar occultations and other targets of opportunity.

The presentation will give an overview over the capabilities of the observatory, including a few illustrative scientific applications. We will discuss the wavelength coverage, sensitivities, and observing modes, as well as limitations that arise from the specifics of an observational platform on-board of an aircraft. Particular emphasis will be given to the recently released "Cycle 7 Call for Proposals", the specific tools necessary for proposal generation, and how to successfully compete for observing time on SOFIA.

2018-07-13
15:00
From VLT to ELT
Signature Speaker Michele Cirasuolo (ESO)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
In this presentation I will discuss three topics: some recent results obtained with KMOS on the physics and dynamics of high galaxies\; the current status of the MOONS instrument and the unprecedented capabilities of the new Extremely Large Telescope (ELT).

First I will discuss the latest results we have obtained from a Large Programme with KMOS called KLEVER. The programme is designed to observe and spatially resolve a sample of ~100 galaxies at 1<\;z<\;2.5 with full near-IR wavelength coverage (YJ,H,K) delivering the (nearly) full set of rest-frame optical nebular lines and therefore an extraordinary diagnostic power.

I will then present a scientific and technical overview of the MOONS instrument, a new multi-object spectrograph for the Very Large Telescope. The combination of high multiplex (1000 targets) and wide simultaneous wavelength coverage (0.64 - 1.8 microns) of MOONS will provide the astronomical community with a powerful, world-leading instrument able to serve a wide range of Galactic and Extragalactic studies.

Finally I will highlight the key science drivers of the new ESO's flagship facility: the Extremely Large Telescope.
The E-ELT is now under construction and with its 39-metre primary mirror it will be the largest optical/near-IR telescope in the world. I will present an overview of the E-ELT Programme, focusing on the latest status of the telescope, its instrumentation and the scientific synergies.

2018-07-13
15:00
From VLT to ELT
Signature Speaker Michele Cirasuolo (ESO)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
In this presentation I will discuss three topics: some recent results obtained with KMOS on the physics and dynamics of high galaxies\; the current status of the MOONS instrument and the unprecedented capabilities of the new Extremely Large Telescope (ELT).

First I will discuss the latest results we have obtained from a Large Programme with KMOS called KLEVER. The programme is designed to observe and spatially resolve a sample of ~100 galaxies at 1<\;z<\;2.5 with full near-IR wavelength coverage (YJ,H,K) delivering the (nearly) full set of rest-frame optical nebular lines and therefore an extraordinary diagnostic power.

I will then present a scientific and technical overview of the MOONS instrument, a new multi-object spectrograph for the Very Large Telescope. The combination of high multiplex (1000 targets) and wide simultaneous wavelength coverage (0.64 - 1.8 microns) of MOONS will provide the astronomical community with a powerful, world-leading instrument able to serve a wide range of Galactic and Extragalactic studies.

Finally I will highlight the key science drivers of the new ESO's flagship facility: the Extremely Large Telescope.
The E-ELT is now under construction and with its 39-metre primary mirror it will be the largest optical/near-IR telescope in the world. I will present an overview of the E-ELT Programme, focusing on the latest status of the telescope, its instrumentation and the scientific synergies.

2018-07-06
15:00
Gamma Rays from The Galactic Centre - an indirect sign for dark matter?
Johannes King (LSW)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Gamma-ray astronomy is an established tool for studying the most energetic, non-thermal processes in the Universe. These processes are typically linked to the acceleration of cosmic rays, which in turn emit gamma-rays for example via inverse compton scattering or the decay of neutral pions. Another process that potentially yields a detecable gamma-ray signal is the annihilation or decay of dark matter particles. Since such a signal is proportional to the dark matter densitiy the Galactic Centre is the ideal place for indirect dark matter searches.

I will present recent studies of the gamma radiation from the Galactic Centre based on observations with H.E.S.S., an array of five imaging atmospheric Cherenkov telescopes located in Namibia. H.E.S.S. plays a major role in the indirect search for dark matter and will continue to do so in the coming years.

2018-07-06
15:00
Gamma Rays from The Galactic Centre - an indirect sign for dark matter?
Johannes King (LSW)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Gamma-ray astronomy is an established tool for studying the most energetic, non-thermal processes in the Universe. These processes are typically linked to the acceleration of cosmic rays, which in turn emit gamma-rays for example via inverse compton scattering or the decay of neutral pions. Another process that potentially yields a detecable gamma-ray signal is the annihilation or decay of dark matter particles. Since such a signal is proportional to the dark matter densitiy the Galactic Centre is the ideal place for indirect dark matter searches.

I will present recent studies of the gamma radiation from the Galactic Centre based on observations with H.E.S.S., an array of five imaging atmospheric Cherenkov telescopes located in Namibia. H.E.S.S. plays a major role in the indirect search for dark matter and will continue to do so in the coming years.

2018-06-29
15:00
Stellar Forensics with the Most Powerful Explosions in the Universe
Maryam Modjaz (NYU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Supernovae (SNe) and Gamma-ray Bursts (GRBs) are exploding stars and constitute the most powerful explosions in the universe. Since they are visible over large cosmological distances, release almost all elements heavier than Helium, and leave behind extreme remnants such as black holes, they are fascinating objects, as well as crucial tools for many areas of astrophysics, including cosmology. However, for many years the fundamental question of which stellar systems give rise to which kinds of explosions has remained outstanding, for both Type Ia SNe used for cosmology as well as for Superluminous SNe and long-duration GRBs that must originate from special kinds of massive stars. I will discuss the exciting recent progress that we have made on this question in key areas by publishing and thoroughly analyzing the largest data sets in the world. I will conclude with an outlook on how the most promising venues of research - using the existing and upcoming innovative large time-domain surveys such as ZTF and LSST - will shed new light on the diverse deaths of stars.

2018-06-29
15:00
Stellar Forensics with the Most Powerful Explosions in the Universe
Maryam Modjaz (NYU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
Supernovae (SNe) and Gamma-ray Bursts (GRBs) are exploding stars and constitute the most powerful explosions in the universe. Since they are visible over large cosmological distances, release almost all elements heavier than Helium, and leave behind extreme remnants such as black holes, they are fascinating objects, as well as crucial tools for many areas of astrophysics, including cosmology. However, for many years the fundamental question of which stellar systems give rise to which kinds of explosions has remained outstanding, for both Type Ia SNe used for cosmology as well as for Superluminous SNe and long-duration GRBs that must originate from special kinds of massive stars. I will discuss the exciting recent progress that we have made on this question in key areas by publishing and thoroughly analyzing the largest data sets in the world. I will conclude with an outlook on how the most promising venues of research - using the existing and upcoming innovative large time-domain surveys such as ZTF and LSST - will shed new light on the diverse deaths of stars.

2018-06-22
13:15
The production of dust in galaxies
Ciska Kemper (ASIAA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The evolution of interstellar dust reservoirs, and the evolution of galaxies themselves go hand-in-hand, as the presence of dust alters evolutionary drivers, such as the interstellar radiation field and the star formation history, while at the same time, the dust is being formed and altered by processes taking place in galaxies. Indeed, dust can often even be used as a tracer of physical conditions. The exact mineralogical composition, the size and the shape of dust grains, are all affected by the physical conditions. Due to the more permanent nature of solids, dust grains provide a historical record of its processing history, while interstellar gas will only ever probe the
present conditions.

I will discuss our recent results on the Magellanic Clouds, Local Group galaxies, the Milky Way, AGN tori, and starburst galaxies, and highlight future observational opportunities open to astronomers to continue the study of interstellar dust in galaxies.

2018-06-22
13:15
The production of dust in galaxies
Ciska Kemper (ASIAA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The evolution of interstellar dust reservoirs, and the evolution of galaxies themselves go hand-in-hand, as the presence of dust alters evolutionary drivers, such as the interstellar radiation field and the star formation history, while at the same time, the dust is being formed and altered by processes taking place in galaxies. Indeed, dust can often even be used as a tracer of physical conditions. The exact mineralogical composition, the size and the shape of dust grains, are all affected by the physical conditions. Due to the more permanent nature of solids, dust grains provide a historical record of its processing history, while interstellar gas will only ever probe the
present conditions.

I will discuss our recent results on the Magellanic Clouds, Local Group galaxies, the Milky Way, AGN tori, and starburst galaxies, and highlight future observational opportunities open to astronomers to continue the study of interstellar dust in galaxies.

2018-06-15
15:00
The chemical evolution of the Sculptor dwarf spheroidal galaxy (and what we can learn from it!)
Ása Skuladottir (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
At current date the Milky Way has over 50 known satellite galaxies, each
with unique properties. Sculptor is one of the classical dwarf spheroidal
galaxies, with a total mass on the order of ~3x10^8 Msun, and a relatively
high stellar mass for a Local Group dwarf galaxy system: ~8x10^6 Msun.
This galaxy is dominated by an old stellar population (>10 Gyr) and is
therefore an ideal system to study early chemical evolution. Currently we
have available detailed chemical abundances (up to 20 different elements)
for over 100 stars, covering the large metallicity range -4.0<[Fe/H]<-0.9,
(as well as less detailed abundances for ~400 stars), making this one of
the best chemically studied galaxy outside of the Milky Way. From the
details of Sculptor's chemical evolution history, we can therefore learn
valuable lessons about dwarf galaxies in general, as well as larger
systems.

2018-06-15
15:00
The chemical evolution of the Sculptor dwarf spheroidal galaxy (and what we can learn from it!)
Ása Skuladottir (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
Show/hide abstract

Abstract
At current date the Milky Way has over 50 known satellite galaxies, each
with unique properties. Sculptor is one of the classical dwarf spheroidal
galaxies, with a total mass on the order of ~3x10^8 Msun, and a relatively
high stellar mass for a Local Group dwarf galaxy system: ~8x10^6 Msun.
This galaxy is dominated by an old stellar population (>10 Gyr) and is
therefore an ideal system to study early chemical evolution. Currently we
have available detailed chemical abundances (up to 20 different elements)
for over 100 stars, covering the large metallicity range -4.0<[Fe/H]<-0.9,
(as well as less detailed abundances for ~400 stars), making this one of
the best chemically studied galaxy outside of the Milky Way. From the
details of Sculptor's chemical evolution history, we can therefore learn
valuable lessons about dwarf galaxies in general, as well as larger
systems.

2018-06-08
15:00
Asteroseismology in the Gaia Era
Marc Pinsonneault (OSU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Stellar oscillations are powerful tools for understanding the structure and evolution of stars. With the advent of time domain space missions they can now be measured for large samples of evolved cool stars. The combination of this asteroseismic data, astrometry from Gaia, and large spectroscopic surveys is transforming our understanding of stellar populations and stellar physics. In this talk I review the current state of the art in red giant asteroseismology: both how well we can measure stellar properties using it and how it has changed our understanding of stellar populations. I will also discuss the powerful combination of asteroseismology and

2018-06-08
15:00
Asteroseismology in the Gaia Era
Marc Pinsonneault (OSU)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Stellar oscillations are powerful tools for understanding the structure and evolution of stars. With the advent of time domain space missions they can now be measured for large samples of evolved cool stars. The combination of this asteroseismic data, astrometry from Gaia, and large spectroscopic surveys is transforming our understanding of stellar populations and stellar physics. In this talk I review the current state of the art in red giant asteroseismology: both how well we can measure stellar properties using it and how it has changed our understanding of stellar populations. I will also discuss the powerful combination of asteroseismology and

2018-06-01
15:00
The Lowest-Mass Galaxies in the Early Universe: Insights from the Local Group
Dan Weisz (UC Berkeley)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The Local Group is home to ~100 galaxies less massive than the Small Magellanic Cloud (10^8 Msun). Such low-mass galaxies have become increasingly relevant to a broad range of astrophysics from cosmic reionization to deciphering the nature of dark matter. Yet, they are simply too faint to be directly detected at any appreciable redshift, compromising our ability to place them into a cosmological context. In this talk, I will describe how observations of resolved stellar populations in Local Group galaxies enable the measurement of detailed star formation histories, which provide the only avenue for tracing the evolution of low-mass galaxies across cosmic time. I will review our current knowledge of low-mass galaxy evolution over 6 decades in stellar mass, with a particular emphasis on the early Universe. I will illustrate how local observations of stars and galaxies can be used in tandem with high-redshift studies to improve our understanding of cosmic reionization. I will conclude by discussing prospects for increased synergy between near-field and far-field galaxy studies in the JWST era.

2018-06-01
15:00
The Lowest-Mass Galaxies in the Early Universe: Insights from the Local Group
Dan Weisz (UC Berkeley)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The Local Group is home to ~100 galaxies less massive than the Small Magellanic Cloud (10^8 Msun). Such low-mass galaxies have become increasingly relevant to a broad range of astrophysics from cosmic reionization to deciphering the nature of dark matter. Yet, they are simply too faint to be directly detected at any appreciable redshift, compromising our ability to place them into a cosmological context. In this talk, I will describe how observations of resolved stellar populations in Local Group galaxies enable the measurement of detailed star formation histories, which provide the only avenue for tracing the evolution of low-mass galaxies across cosmic time. I will review our current knowledge of low-mass galaxy evolution over 6 decades in stellar mass, with a particular emphasis on the early Universe. I will illustrate how local observations of stars and galaxies can be used in tandem with high-redshift studies to improve our understanding of cosmic reionization. I will conclude by discussing prospects for increased synergy between near-field and far-field galaxy studies in the JWST era.

2018-05-18
15:00
detecting optimal targets for characterization & understanding
Nestor Espinoza (MPIA) : Transiting exoplanets
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Transiting exoplanets are exciting objects to study because, with sufficient follow-up, they can be almost completely characterized. From bulk and atmospheric compositions to a plethora of orbital information, these exoplanets can provide key information that, in principle, enable us to build (and test) models to understand how they are shaped to their present-day forms. However, only a handful of transiting exoplanets "optimal" for characterization exist, despite the large number of confirmed transiting exoplanets detected to date\; their detection and characterization is thus an important challenge on its own. In this talk, I will present our on-going efforts with the K2-CL collaboration to find new, interesting characterizable systems with the K2 mission, how and why these have to be followed up after their discovery to keep their ephemerides up to date, and our efforts within the ACCESS survey, with which we are exploring exoplanet atmospheres of interesting targets in the optical window, which is key to unveil what their atmospheres are made of, specially if combined with HST/WFC3 data. Lessons learned and natural transitions of these projects in light of the upcoming TESS and JWST missions will be discussed.

2018-05-18
15:00
detecting optimal targets for characterization & understanding
Nestor Espinoza (MPIA) : Transiting exoplanets
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Transiting exoplanets are exciting objects to study because, with sufficient follow-up, they can be almost completely characterized. From bulk and atmospheric compositions to a plethora of orbital information, these exoplanets can provide key information that, in principle, enable us to build (and test) models to understand how they are shaped to their present-day forms. However, only a handful of transiting exoplanets "optimal" for characterization exist, despite the large number of confirmed transiting exoplanets detected to date\; their detection and characterization is thus an important challenge on its own. In this talk, I will present our on-going efforts with the K2-CL collaboration to find new, interesting characterizable systems with the K2 mission, how and why these have to be followed up after their discovery to keep their ephemerides up to date, and our efforts within the ACCESS survey, with which we are exploring exoplanet atmospheres of interesting targets in the optical window, which is key to unveil what their atmospheres are made of, specially if combined with HST/WFC3 data. Lessons learned and natural transitions of these projects in light of the upcoming TESS and JWST missions will be discussed.

2018-05-11
15:00
Exploring the Evolution of Circumstellar Disks with ALMA
John Carpenter (Joint ALMA Observatory)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
ALMA is providing new opportunities to explore the evolution of circumstellar disks. From snapshot surveys of protoplanetary disks in nearby star forming regions, to sensitive high-resolution images of young disks, and to surveys of old debris disks, ALMA is tracing the structure and properties of disks at all evolutionary stages. This talk will present recent ALMA observations that are contributing to our understanding of the properties of protoplanetary and debris disks. I will first summarize the results from recent ALMA surveys that are establishing the demographics of protoplanetary disks between ages of 1 and 10 Myr. I will also present new high-resolution images of 20 protoplanetary disks from an ALMA Large Program that is designed to determine the prevalence of substructure (e.g., rings, spirals, and gaps) in young protoplanetary disks. Finally, I will present new ALMA data for a debris disk around a ~ 100 Myr old solar analog and discuss the implications for planet formation in this system.

2018-05-11
15:00
Exploring the Evolution of Circumstellar Disks with ALMA
John Carpenter (Joint ALMA Observatory)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
ALMA is providing new opportunities to explore the evolution of circumstellar disks. From snapshot surveys of protoplanetary disks in nearby star forming regions, to sensitive high-resolution images of young disks, and to surveys of old debris disks, ALMA is tracing the structure and properties of disks at all evolutionary stages. This talk will present recent ALMA observations that are contributing to our understanding of the properties of protoplanetary and debris disks. I will first summarize the results from recent ALMA surveys that are establishing the demographics of protoplanetary disks between ages of 1 and 10 Myr. I will also present new high-resolution images of 20 protoplanetary disks from an ALMA Large Program that is designed to determine the prevalence of substructure (e.g., rings, spirals, and gaps) in young protoplanetary disks. Finally, I will present new ALMA data for a debris disk around a ~ 100 Myr old solar analog and discuss the implications for planet formation in this system.

2018-05-04
15:00
Jupiter's Jet-Streams and interior revealed by Juno
Yamila Miguel (Leiden)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract

Giant planets were the first planets to form and the most influential ones. Their interiors and atmospheres have crucial information to understand the origins of the solar system and of our own Earth.  \;

With the aim to reach a deeper understanding of Jupiter's interior and atmosphere, the Juno spacecraft was sent to the biggest giant in the solar system, and its first results have fundamentally changed our understanding of this planet. \;


In this seminar I will show the models we use to understand Jupiter's interior and our latest Juno results -including a much deeper understanding of Jupiter's interior and jet streams-, that will help us to reach a better understanding of Jupiter formation history.


2018-05-04
15:00
Jupiter's Jet-Streams and interior revealed by Juno
Yamila Miguel (Leiden)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract

Giant planets were the first planets to form and the most influential ones. Their interiors and atmospheres have crucial information to understand the origins of the solar system and of our own Earth.  \;

With the aim to reach a deeper understanding of Jupiter's interior and atmosphere, the Juno spacecraft was sent to the biggest giant in the solar system, and its first results have fundamentally changed our understanding of this planet. \;


In this seminar I will show the models we use to understand Jupiter's interior and our latest Juno results -including a much deeper understanding of Jupiter's interior and jet streams-, that will help us to reach a better understanding of Jupiter formation history.


2018-04-27
15:00
Neutron star mergers and the high-density equation of state
Andreas Bauswein (HITS)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
In August 2017 the LIGO-Virgo network detected for the first time gravitational waves from a neutron star merger. The event, dubbed GW170817, was followed by electromagnetic radiation. Various emission mechanisms produced radiation at different wavelengths throughout the electromagnetic spectrum from gamma rays to radio. The gravitational and electromagnetic radiation has provided a wealth of information on the physics of neutron star mergers. In particular, it was possible to infer constraints on stellar properties of neutron stars and the only incompletely known equation of state of high-density matter. Specifically, bounds on neutron star radii have been derived from this very first observation of a neutron star merger. Future detections with increased sensitivity promise accurate and robust measurements of neutron star properties and thus to elucidate properties of high-density matter.

2018-04-27
15:00
Neutron star mergers and the high-density equation of state
Andreas Bauswein (HITS)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
In August 2017 the LIGO-Virgo network detected for the first time gravitational waves from a neutron star merger. The event, dubbed GW170817, was followed by electromagnetic radiation. Various emission mechanisms produced radiation at different wavelengths throughout the electromagnetic spectrum from gamma rays to radio. The gravitational and electromagnetic radiation has provided a wealth of information on the physics of neutron star mergers. In particular, it was possible to infer constraints on stellar properties of neutron stars and the only incompletely known equation of state of high-density matter. Specifically, bounds on neutron star radii have been derived from this very first observation of a neutron star merger. Future detections with increased sensitivity promise accurate and robust measurements of neutron star properties and thus to elucidate properties of high-density matter.

2018-04-20
15:00
10 years of Galaxy Evolution
Arjen van der Wel (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
To conclude my ~10-year stay at MPIA I will give an overview of the progress in understanding the formation and evolution of galaxies that we have made over the past decade. This summary will be broad, ranging from theory and simulations to the observations of distant star-bursting dwarf galaxies, but from the specific perspective provided by large optical/near-IR surveys. I will describe how MPIA has stood at the forefront of the transition from an era of discovery -- which showed where the stars in the universe are and when they formed --  \;to an era of concrete physical insight in to the galaxy evolution process.

2018-04-20
15:00
10 years of Galaxy Evolution
Arjen van der Wel (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
To conclude my ~10-year stay at MPIA I will give an overview of the progress in understanding the formation and evolution of galaxies that we have made over the past decade. This summary will be broad, ranging from theory and simulations to the observations of distant star-bursting dwarf galaxies, but from the specific perspective provided by large optical/near-IR surveys. I will describe how MPIA has stood at the forefront of the transition from an era of discovery -- which showed where the stars in the universe are and when they formed --  \;to an era of concrete physical insight in to the galaxy evolution process.

2018-04-13
15:00
High-resolution cosmological simulations of Milky Way mass galaxies"
Tobias Buck (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The Milky Way and its dwarf galaxy companions are among the most well studied galaxy we know.
Current very high-resolution zoom-in baryonic simulations of the formation of Milky Way mass galaxies are in incredible
agreement with observed properties our Milky Way. First, I will introduce the new high-resolution set of simulations from the NIHAO project and discuss the formation of the Milky Way. I will cover the early phases of violent star formation and the accretion of its satellites providing observational constraints on the effect of environment dwarf galaxy properties. I will further discuss the (kinematic) structure and evolution of the stellar disc and the morphology and abundance patterns of the Milky Way's central region - its bar and boxy/peanut bulge. Using these simulations I am able to provide a theoretical understanding of the formation of the Milky Way in the era of Gaia.

2018-04-13
15:00
High-resolution cosmological simulations of Milky Way mass galaxies"
Tobias Buck (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
The Milky Way and its dwarf galaxy companions are among the most well studied galaxy we know.
Current very high-resolution zoom-in baryonic simulations of the formation of Milky Way mass galaxies are in incredible
agreement with observed properties our Milky Way. First, I will introduce the new high-resolution set of simulations from the NIHAO project and discuss the formation of the Milky Way. I will cover the early phases of violent star formation and the accretion of its satellites providing observational constraints on the effect of environment dwarf galaxy properties. I will further discuss the (kinematic) structure and evolution of the stellar disc and the morphology and abundance patterns of the Milky Way's central region - its bar and boxy/peanut bulge. Using these simulations I am able to provide a theoretical understanding of the formation of the Milky Way in the era of Gaia.

2018-04-06
15:00
The second Gaia data release
Coryn Bailer-Jones (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract

On 25 April the Gaia Consortium will make its second data release based
on 22 months of mission data. The release will contain five-parameter
astrometry and three-band photometry for over 1 billion stars down to
G=20.7, radial velocities for 7 million stars, variability
classification for several hundred thousand stars, plus basic stellar
parameters for up to 160 million stars. I will give an overview of the
content, precision, and coverage of this release plus some tips on how
(not) to use the data.

2018-04-06
15:00
The second Gaia data release
Coryn Bailer-Jones (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract

On 25 April the Gaia Consortium will make its second data release based
on 22 months of mission data. The release will contain five-parameter
astrometry and three-band photometry for over 1 billion stars down to
G=20.7, radial velocities for 7 million stars, variability
classification for several hundred thousand stars, plus basic stellar
parameters for up to 160 million stars. I will give an overview of the
content, precision, and coverage of this release plus some tips on how
(not) to use the data.

2018-03-23
15:00
The Role of Environment in Shaping Molecular Cloud Structure and Star Formation
Chris Faesi (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Giant Molecular Clouds (GMCs) are the cradles of stellar birth across the universe and thus play a key role in the baryon cycle within galaxies. GMCs in the Milky Way show a high degree of uniformity in their physical structure, but recent observations of nearby galaxies have suggested that their properties may vary systematically with environment. To explore the question of universality vs. environment, I have undertaken a series of high-resolution, high-sensitivity studies of molecular gas and star formation in NGC 300, a low mass, star forming spiral galaxy that at a distance of 2 Mpc provides an ideal laboratory for resolved GMC studies and comparison to our own Galaxy. I will describe the results of a campaign of multiwavelength observations of NGC 300 culminating in an ALMA study that achieves 10 pc resolution, fully resolving GMC scales in a sample of 250 clouds. I will show that despite large differences between global properties of the Milky Way and NGC 300, their GMC populations appear to be remarkably similar. Furthermore, the relationship between star formation and molecular gas identified in the Milky Way also holds in NGC 300. I will demonstrate that local physical properties such as midplane disk pressure of the interstellar medium, which is similar between the Milky Way and NGC 300, may explain observed differences in GMC properties in other galaxies such as M51, as well as in more extreme physical environments such as the Galactic Center. I will conclude by describing the ongoing campaign to link small-scale interstellar medium physics with large-scale galaxy properties under the auspices of the PHANGS (Physics at High Angular resolution in Nearby GalaxieS) collaboration. We have in-progress large programs with both ALMA and MUSE to measure molecular gas and tracers of star formation at arcsecond resolution across the disks of tens of galaxies, providing improved statistics and greatly expanding the parameter space for GMC-scale analyses in a range of environments.

2018-03-16
15:00
Crowded field 3D spectroscopy in NGC300 - spectacular details of resolved stellar populations revealed through the combination of ACS with MUSE
Martin Roth (AIP)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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Abstract
Already a decade ago, the Advanced Camera for Surveys Nearby Galaxy survey Treasury (ANGST) has provided images and photometry of individual stars in nearby galaxies, thus furnishing the hope to provide deep insight into star formation histories and the chemical evolution of galaxies. However, the known limitations of photometry have remained an obstacle to fully exploit the angular resolution of HST in analyzing stellar populations in galaxies such as the sculptor group galaxy NGC300. We have selected NGC300 as the target of our MUSE GTO program at the VLT UT4 to explore the potential of IFUs for crowded field 3D spectroscopy, utilizing PSF-fitting techniques that have become a standard for imaging data in the optical and NIR already for some time (DAOPHOT etc.). With the input of stellar centroids obtained from the ANGST catalogue, we are demonstrating that the PampelMuse PSF-fitting tool is capable to extract more than 500 spectra for individual stars of luminosity class I?III from a single MUSE pointing (1.5 h exposure time). These spectra are well deblended and allow for spectral type classification as well as the measurement of radial velocities. Next to stars of spectral types O?M, we find numerous carbon stars, blue emission line stars, and LBV and symbiotic star candidates. The excellent image quality and sensitivity of MUSE has also enabled the discovery of extremely faint HII regions, planetary nebulae, supernova remnants, and substructure of the diffuse ionized gas (DIG).

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