Ruprecht-Karls-Universität Heidelberg

Königstuhl Kolloquium


Upcoming events


2018-11-16
15:00
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Rowan Smith (University of Manchester)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2018-11-16
15:00
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Rowan Smith (University of Manchester)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2018-11-23
15:00
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Bertram Bitsch (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2018-11-23
15:00
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Bertram Bitsch (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2018-11-30
15:00
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Patzer Colloquium
TBA (TBA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2018-11-30
15:00
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Patzer Colloquium
TBA (TBA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2018-12-07
15:00
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HHSF18
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2018-12-07
15:00
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HHSF18
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2018-12-14
15:00
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Karin Lind (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2018-12-14
15:00
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Karin Lind (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2019-01-18
15:00
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Jeroen Bouwman (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2019-01-18
15:00
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Jeroen Bouwman (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)

2019-01-25
15:00
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Yuan Wang (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2019-01-25
15:00
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Yuan Wang (MPIA)
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2019-03-22
15:00
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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
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Paola Di Matteo (GEPI/Obs. de Paris)
: Signature Speaker
Königstuhl Kolloquium
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)


Past events


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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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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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)
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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.

2018-08-03
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)
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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.

2018-07-13
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)
Show/hide abstract

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)
Show/hide abstract

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)
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.

2018-06-29
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)
Show/hide abstract

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)
Show/hide abstract

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)
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.

2018-06-15
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)
Show/hide abstract

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)
Show/hide abstract

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)
Show/hide abstract

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)
Show/hide abstract

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)
Show/hide abstract

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)
Show/hide abstract

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)
Show/hide abstract

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)
Show/hide abstract

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)
Show/hide abstract

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)
Show/hide abstract

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)
Show/hide abstract

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)
Show/hide abstract

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)
Show/hide abstract

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)
Show/hide abstract

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)
Show/hide abstract

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)
Show/hide abstract

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)
Show/hide abstract

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)
Show/hide abstract

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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