Events, Seminars, Talks

Abstract
Hot massive stars are observed both individually in the Galaxy and in its nearest neighbors, as well as in the integrated light of galaxies at cosmic dawn. In this talk I focus on massive stars and populations in galaxies at distance of a few to hundreds of Mpc. These “Local” galaxies are at a sweet spot where detailed studies of stellar properties are still feasible but at the same time global galaxy properties are available as well. Local galaxies can therefore serve as bridges between stellar astrophysics and observational cosmology. I will discuss our ongoing research on these galaxies and present new results on the stellar properties, chemical abundances and evolution, galactic outflows and escaping ionizing radiation into the intergalactic medium. Those unable to attend the colloquium in person are invited to participate online through Zoom (Meeting ID: 942 0262 2849, passcode 792771) using the link: https://eu02web.zoom-x.de/j/94202622849?pwd=dGlPQXBiUytzY1M2UE5oUDRhbzNOZz09 During his visit to Heidelberg, Dr. Leitherer will be available for meetings by arrangement with his host, Andreas Sander (andreas.sander@uni-heidelberg.de).

Abstract
Supermassive black holes are thought to exist in the centres of most massive galaxies and their masses have been found to correlate strongly with the properties of their host galaxies like overall luminosity or central velocity dispersion. Yet it is unknown what processes have established these correlations and if and how they continue towards lower mass systems. In my talk I will present results from our search for massive black holes in ultra-compact dwarf galaxies and in massive globular clusters of the Milky Way.

Abstract
TBA

Abstract
Polycyclic Aromatic Hydrocarbons (PAHs) have been implicated as a large reservoir of reactive carbon in the interstellar medium since the 1980s.  PAHs have been widely attributed as the carriers of the unidentified infrared bands where their aggregate vibrational emission spectra are extremely well matched to the observed line signals.  Only in the last year have individual PAHs been detected in the ISM for the first time, however, allowing us to begin to investigate the detailed chemical pathways for the formation and destruction of these molecules.  In this talk, I will discuss our detections of PAH molecules via their rotational transitions using Green Bank Telescope observations of TMC-1 from the GOTHAM collaboration.  I will discuss the efforts to model the chemistry of these PAHs, our application of novel machine learning approaches to exploring the chemical inventory in TMC-1, and finally the benefits of unbiased reaction screening studies in the laboratory with Microwave Spectral Taxonomy.

Abstract
The processes regulating star formation in galaxies act across many orders of magnitude in spatial scale. Thus, a key challenge in understanding star formation is bridging the small-scale physics within molecular clouds and the large-scale structure of spiral galaxies. Fully constraining the physics of star formation across these scales requires constraints on both the 3D spatial structure and dynamical state of the interstellar medium (ISM), the combination of which has been an essentially unknown quantity in the field of star formation research. In this talk, I will discuss ongoing efforts to construct high-dimensional models of the ISM in the solar neighborhood by combining data science and visualization techniques with wide-field photometric, astrometric, and spectroscopic surveys. On kiloparsec scales, I will discuss how "3D dust mapping" has enabled constraints on the global distribution of molecular clouds, revealing new links between clouds long thought to be isolated and challenging fundamental assumptions about the shape and position of a nearby spiral arm. On parsec scales, I will show how combining 3D dust mapping with the 3D space motions of young stars can explain the origin of local star formation as being driven by the expansion of the Local Bubble, the nearest superbubble to the Sun. Finally, on au-scales, I will discuss the implications that the Sun’s trajectory through the ISM has for the properties of the heliosphere and the geological record here on Earth. I will conclude by previewing the opportunities enabled by future infrared surveys, including SDSS-V and Roman, which together will pave the way for a unified understanding of the multi-scale physical processes shaping star formation in diverse environments across the Milky Way’s disk. Those unable to attend the colloquium in person are invited to participate online through Zoom (Meeting ID: 942 0262 2849, passcode 792771) using the link: https://eu02web.zoom-x.de/j/94202622849?pwd=dGlPQXBiUytzY1M2UE5oUDRhbzNOZz09 During her visit to Heidelberg, Professor Zucker will be available for meetings by arrangement with her host, Ralf Klessen (klessen@uni-heidelberg.de)

Abstract
Identifying and characterizing the processes that transform galaxies from star-forming to quiescent is a fundamental goal of extragalactic astronomy. One critical transformation mechanism is galactic-scale feedback due to active nuclei (AGN). In an ongoing collaboration between Brazil (UFSM - Santa Maria, UFRGS - Porto Alegre and UNIVAP - São José dos Campos) and Germany (ARI - Heidelberg, AIP - Potsdam), our goal is to investigate the impact of AGN feedback in galaxy through the study the properties of multi-gas phase AGN winds, stellar populations, environmental effects, and chemical abundances of AGN hosts. In this talk, I will introduce the collaboration and present previous results obtained by our group. We have been studying the AGN feeding and feedback processes over 15 years, using optical and near-infrared integral field spectroscopy of inner kiloparsec of nearby active galaxies obtained with large telescopes. These observations are used to spatially resolve the molecular and ionized gas emission structure and kinematics. We find that while outflows in ionized gas are seen in most objects studied, in molecular gas they are less common, which usually is dominated by rotation in the disk of galaxies and shows inflows in some cases. The observed ionized outflows are not powerful enough to effectively quench star formation in the AGN host galaxies in most cases.

Abstract
TBA

Abstract
TBA

Abstract
tba

Abstract
TBD

Abstract
TBD

Abstract
TBA

Abstract
TBA

Abstract
TBA

Abstract
tbd

Abstract
tbd

Abstract
TBA

Abstract
TBD

Abstract
TBD

Abstract
TBD

Abstract
TBA

Abstract
TBD

Abstract
TBD

Abstract
TBD