Ruprecht-Karls-Universität Heidelberg

Events, Seminars, Talks

A list of all Physics & Astronomy talks and seminars taking place in Heidelberg can be found at HePhySTO.


Upcoming events


2020-12-04
15:00
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Star Formation in the Turbulent-Multiphase Interstellar Medium
Shmuel Bialy (CfA)
Königstuhl Kolloquium ( Home pageHephysto link )
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).

2020-12-08
16:00
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The genesis of the first elements
Ryan Cooke (Durham University)
Heidelberg Joint Astronomical Colloquium ( Home pageHephysto link )
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2020-12-08
16:00
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The puzzle of multiple populations in globular clusters
Nate Bastian (LJMU)
Heidelberg Joint Astronomical Colloquium ( Home pageHephysto link )
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Abstract
Globular clusters (GCs) exhibit star-to-star variations in specific elements (e.g., He, C, N, O, Na, Al) that bear the hallmark of high-temperature H-burning. These abundance variations can be observed spectroscopically and also photometrically, with the appropriate choice of filters, due to the changing of spectral features within the band pass. This phenomenon is observed in nearly all of the ancient GCs, and has recently been found in many younger clusters as well. Many scenarios have been suggested to explain this phenomenon, with most invoking multiple epochs of star formation within the cluster; however, all have failed to reproduce various key observations. I will review the state of current observations and outline the successes and failures of some of the main proposed models. The traditional idea of using the stellar ejecta from a first generation of stars to form a second generation of stars, while conceptually straightforward, has failed to reproduce an increasing number of observational constraints. I conclude that the puzzle of multiple populations remains unsolved, hence alternative theories are needed, and will present new HST and VLT/MUSE results that suggest that we may be finally closing in on origin of this enigmatic phenomenon.

2020-12-10
11:15
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Gaia Early Data Release 3
Stefan Jordan (ARI)
ARI Institute Kolloquium ( Hephysto link )
ARI, Moenchhofstrasse 12-14, Seminarraum 1, 1.OG
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Abstract
On December 3, 2020, the first (early) part of Gaia’s third star catalogue will be published. Based on 34 months of Gaia observations it contains a significant increase in the number of entries compared to Gaia DR2: position measurements of more than 1.8 billion stars as well as proper motions, parallaxes, and broad-band photometry for about 1.4 billion stars. Additionally, both the precision and accuracy of the astrometric data has significantly improved, especially the determination of proper motions. Together with the release of the star catalogue, four papers are published, impressively demonstrating the scientific potential of the Gaia EDR3 catalogue.

2020-12-11
15:00
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Stellar clustering connecting the formation and evolution of galaxies to the formation and evolution of us
Diederik Kruijssen (Heidelberg University)
Königstuhl Kolloquium ( Home pageHephysto link )
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.

2020-12-15
16:00
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Red-giant stars inside out
Saskia Hekker (HITS/Heidelberg University)
Heidelberg Joint Astronomical Colloquium ( Home pageHephysto link )
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Abstract
Did you know that we can probe the core of a red-giant star better than the core of the Sun? Actually, we do thanks to oscillations that are sensitive to the core that can be observed on the stellar surface. Over the past decade this has led to several groundbreaking discoveries. In this talk I will discuss these discoveries and explain how it is possible to look into the core of a red giant and not into the Sun.

2020-12-17
11:15
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Science Forgeries, Fraud, Fake Science Across Scientific Disciplines and Their Consequences
Eva Grebel (ARI)
ARI Institute Kolloquium ( Hephysto link )
ARI, Moenchhofstrasse 12-14, Seminarraum 1, 1.OG
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Abstract
The above was the subject of a Marsilius Project at Heidelberg University undertaken jointly by the art historian Prof. Henry Keazor and myself, triggered by my experiences in the DFG commission for investigations of scientific misconduct and his work on exposing art forgeries. I will present a summary of our findings on the different types of such misconduct across different disciplines, discuss the motivation of the perpetrators and ways of preventing misconduct, as well as talk about the consequences for science, scientific credibility, political and economic decisions, and public perception in general.

2020-12-18
15:00
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TBA
Laura Kreidberg (MPIA)
Königstuhl Kolloquium ( Home pageHephysto link )
Via zoom link. Please contact organisers if you need the zoom information.,
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2021-01-08
15:00
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Connecting the dots: Numerical models of AGN and their particle acceleration
F. Spanier (ITA)
Königstuhl Kolloquium ( Home pageHephysto link )
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?"

2021-01-12
16:00
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Hot takes on cool worlds: exoplanet atmosphere characterization in the 2020s
Laura Kreidberg (MPIA)
Heidelberg Joint Astronomical Colloquium ( Home pageHephysto link )
Zoom,

2021-01-14
11:15
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The power of asteroseismology: the internal structure of stars
Saskia Hekker (HITS and LSW)
ARI Institute Kolloquium ( Hephysto link )
ARI, Moenchhofstrasse 12-14, Seminarraum 1, 1.OG
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Abstract
Over the past decade the space missions CoRoT, Kepler and TESS have revolutionised the field of asteroseismology ? the study of the internal structures of stars through their global intrinsic oscillations. A particular steep increase in our knowledge has been possible in stars cooler than ~ 6700 K, which exhibit convection in their outer layers. Oscillations are excited in these turbulent layers that allow us to probe large parts of the stars. In this talk I will present recent results of asteroseismic inferences of the stellar structure of these cool stars.

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

2021-01-19
16:00
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Space asteroseismology: the Renaissance of stellar interiors
Conny Aerts (KU Leuven)
Heidelberg Joint Astronomical Colloquium ( Home pageHephysto link )
Zoom,

2021-01-21
11:15
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Refining the picture of galaxy regulation with observations & theory
Benjamin Keller (ARI)
ARI Institute Kolloquium ( Hephysto link )
ARI, Moenchhofstrasse 12-14, Seminarraum 1, 1.OG
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Abstract
Stellar feedback connects the smallest, densest scales of the galaxy to the largest, most diffuse components of the galaxy halo. The detailed, fractal structure of the interstellar medium (ISM) and the evolution of stars sets the local coupling efficiency of energy from stellar winds, radiation and supernovae. This feedback can then drive outflows from most galaxies, removing mass and metals to the diffuse, hot circumgalactic medium. This low-density halo can act as a reservoir for material, slowly allowing it to re-accrete and fuel ongoing star formation. This in turn influences the formation of new molecular clouds within the ISM, connecting the process of star formation to all scales of the galaxy's gas content. In this talk, I will present recent results that have helped to clarify the details as to how the details of these processes can impact the overall life of galaxies, and how we can use new observational and statistical methods to constrain these details.

2021-01-22
15:00
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TBA
Trifon Trifonov (MPIA)
Königstuhl Kolloquium ( Home pageHephysto link )
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2021-01-26
16:00
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The fast rotating and low-turbulence discs of high-redshift galaxies
Filippo Fraternali (University of Groningen)
Heidelberg Joint Astronomical Colloquium ( Home pageHephysto link )
Zoom,

2021-01-28
11:15
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The role of star formation environment for planet formation
Andrew Winter (ITA)
ARI Institute Kolloquium ( Hephysto link )
ARI, Moenchhofstrasse 12-14, Seminarraum 1, 1.OG
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Abstract
The diverse architectures of discovered exoplanetary systems have provoked an equally diverse range of explanations of the processes governing their formation and evolution. However, the star formation environment is a factor that is frequently overlooked in studies that aim to synthesise the observed planet properties. I review the growing evidence suggesting that environmental feedback plays a significant role during and after planet formation. Two mechanisms that may be particularly influential are external photoevaporation due to irradiation of the protoplanetary disc by neighbouring OB stars, and subsequently star-star encounters that can generate instability in the mature planetary system. I discuss observational constraints and examples of these mechanisms caught in the act, and how they might alter a system from that which forms ?in isolation'. Finally, I contextualise the Solar System in terms of possible environmental sculpting.

2021-01-29
15:00
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Sarah Bosman (MPIA)
Königstuhl Kolloquium ( Home pageHephysto link )
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2021-02-04
11:15
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Microlensing events all over the sky - the promise of large-scale surveys
Markus Hundertmark (ARI)
ARI Institute Kolloquium ( Hephysto link )
ARI, Moenchhofstrasse 12-14, Seminarraum 1, 1.OG
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Abstract
Modern wide-field surveys will provide us with alert streams generating millions of alerts every night and by that providing a comprehensive picture of the variable sky. Traditionally, microlensing events have been found in the most crowded place in the Milky Way. Thanks to the footprint, microlensing events in the disk will play an increasingly important role. The opportunities opening up by these surveys will lead to more discoveries and the characterization of extrasolar planets (bound and unbound), black holes and insights into the binarity of stars and brown dwarfs. The most audacious surveys will certainly provide the best alert stream but some of the aforementioned science cases still require automated follow-up observations. The "fire-hose of alerts" demands cloud-based tools to trigger heterogeneous follow-up observations with a homogeneous software package - the TOM (Target and Observation Manager) Toolkit. We will show early results from the most recent observing programs running at Las Cumbres Observatory (LCO) global network using a TOM and how that can be applied to the surveys of the future.

2021-02-05
15:00
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Gaia & the fingerprints of the Galactic bar ? a dynamical Milkay Way mystery
Wilma Trick (MPA)
Königstuhl Kolloquium ( Home pageHephysto link )
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2021-02-11
11:15
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Ready for the next gravitational million-body simulations: Evolution of single and binary stars in NBODY6++GPU and MOCCA
Albrecht Kamlah (ARI)
ARI Institute Kolloquium ( Hephysto link )
ARI, Moenchhofstrasse 12-14, Seminarraum 1, 1.OG
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Abstract
Direct N-body simulations are the only simulation method capable of properly resolving dense star clusters from the scales between close interacting stars in a binary all the way up to their interaction with distant halo stars. Nevertheless, they are frequently complemented with approximate Monte-Carlo methods, because these are much quicker computationally. Recently, there have been a number of code advances concerning the stellar evolution. This is crucial, as the evolution of individual stars has a huge effect on the overall dynamical evolution of a star cluster and thus amongst others the formation of gravitational wave emitting sources that may be detectable with LIGO and VIRGO. In this talk, I will highlight the state of stellar evolution routines in the direct N-body code NBODY6++GPU and the Henon-type Monte-Carlo code MOCCA by comparing the results of small star cluster simulations performed with both. The results of these are important groundwork to ensure that the upcoming million-body simulations of globular and nuclear star clusters are astrophysically up-to-date.

2021-02-12
15:00
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Dominika Wylezalek (ZAH/ARI)
Königstuhl Kolloquium ( Home pageHephysto link )
Max-Planck-Institut für Astronomie, Level 3 Lecture Hall (301)
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2021-02-16
16:00
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Cosmic alchemy in the era of gravitational wave astronomy
Enrico Ramirez-Ruiz (UC Santa Cruz)
Heidelberg Joint Astronomical Colloquium ( Home pageHephysto link )
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The source of about half of the heaviest elements in the Universe has been a mystery for a long time. Although the general picture of element formation is well understood, many questions about the astrophysical details remain to be answered. Here I focus on recent advances in our understanding of the origin of the heaviest and rarest elements in the Universe.

2021-02-18
11:15
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Breaching the barrier: dynamical formation of the first intermediate-mass black hole discovered by LIGO-Virgo
Manuel Arca Sedda (ARI)
ARI Institute Kolloquium ( Hephysto link )
ARI, Moenchhofstrasse 12-14, Seminarraum 1, 1.OG
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Abstract
On September 2nd 2020, the LIGO-Virgo collaboration announced the detection of GW190521, a gravitational wave source associated with the merger of two black holes (BHs), 66 and 85 Mo masses, which left behind an intermediate-mass black hole (IMBH) with a mass of 142 Mo. This binary merger is peculiar because its primary mass falls in the so-called upper mass-gap, a region of stellar masses where modern stellar evolution predicts the absence of remnants, and the final remnant represents the first specimen of a "light" IMBH. In this seminar, I will describe a novel channel suitable to explain the properties of GW190521, namely a sequence of three mergers among stellar mass black holes. We discovered serendipitously such a process in a high-resolution N-body model of a dense star cluster. We combine these simulations with an analysis based on numerical relativity fitting formulae and on observed properties of globular, young, and nuclear clusters, to show that if GW190521 originated via such a mechanism its observation gives us insights on the distribution of stellar BH natal spins and on the environment that harboured such a system, most likely a dense and young star cluster.

2021-02-25
11:15
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Formation and evolution of supermassive black holes.
Melanie Habouzit (MPIA and LSW)
ARI Institute Kolloquium ( Hephysto link )
ARI, Moenchhofstrasse 12-14, Seminarraum 1, 1.OG
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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 are crucial to understand BH growth and their interplay with their host galaxies. We recently compared the black hole population of six of these large-scale cosmological simulations (Illustris, TNG100, TNG300, Horizon-AGN, EAGLE, and SIMBA) and I will review 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, and LISA. I will present how we can use cosmological simulations to prepare these missions and maximize their scientific return.

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

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