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• 06.02.2026 - Shivam Joshi (Uni. Vie) & Claire Roney (Dept. of Communication, Uni Vie)

  Shivam Joshi (Uni. Vie)

  Rethinking Dust–Gas Coupling in Gas-Rich Debris Discs: The Case of HD 131488 in Scattered Light and Thermal Emission

  Abstract - Debris discs are traditionally treated as gas-poor, optically thin dust rings -- similar to our Solar systems. Yet the growing number of gas detections is forcing us to rethink how dust – gas interactions shape the structure of planetesimal belts. HD 131488 is an especially interesting case as it is a remarkably narrow, bright ring with a substantial amount of CO gas comparable to that of old protoplanetary discs. We model HD131488 in both thermal emission and scattered light in a self-consistent approach to reproducing the disc as seen by ALMA and VLT/SPHERE. Our modelling shows that the large particles seen at ALMA wavelengths and often assumed to trace the planetesimal belt might be off-set from the actual parent belt. A sufficiently dense gas component could both (i) broaden the distribution of small grains seen in scattered light and (ii) trap and pull larger grains inwards towards the pressure maximum, naturally producing the narrow ring as seen with ALMA. Our model explains the morphology of HD 131488 and highlights how strong dust–gas coupling may operate in gas-rich debris discs.

  Claire Roney (Dept. of Communication, Uni Vie)

  Tread Carefully: The Challenges of Communicating Uncertainty in Politicized Contexts

  Studies have shown that uncertainty is decreasing in science communication to public-facing audiences, from research publications to press releases and media articles. Research tells us that there are several potential reasons, among them that scientists fear uncertainties will be instrumentalized by political interest groups and public misunderstanding could brew mistrust in science. Yet, to what extent that perception holds and how scientists understand uncertainty plays a role in their communication, we do not yet fully understand. This research will present preliminary findings from two dissertation papers related to (1) our current understanding of uncertainty among disciplinarily diverse scientists and (2) the challenges scientists encounter in communicating uncertainty, summarizing findings from extant literature on how the communication of uncertainties impacts attitudes toward science.
• 30.01.2026 - Prem Kumar (Uni. Vienna) & Petra Schönfelder (Uni. Vienna)

  Prem Kumar (Uni. Vienna)

  Orbital decomposition and evolution of LEGA-C-like simulated galaxies

  Stellar orbits provide a fossil record of galaxy assembly, yet how different orbital components emerge and evolve across cosmic time remains unclear. In this seminar, I will discuss the first part of my doctorate project, using orbit-based decompositions of LEGA-C–like galaxies at z = 1 drawn from the IllustrisTNG simulation.

  Using time-averaged circularity, galaxies are decomposed into cold, warm, hot, and counter-rotating orbital components and traced to their z = 0 descendants via merger trees, allowing me to show how these components evolve from z = 1 to the present day. In particular, I will show how mergers of different types (major rich/poor, major/minor, wet/dry) affect the orbital components, especially the hot and warm components. I will further show how these evolving orbital structures help reveal the transition from rotation- to dispersion-dominated systems and establish the dynamical diversity of present-day galaxies.

  This work establishes a link between the hierarchical assembly of galaxies and the evolution of their orbital structures, laying the groundwork for applying Schwarzschild orbit-superposition models with DYNAMITE to observed z = 1 galaxies from the LEGA-C survey, thus directly bridging simulations and observations at this pivotal epoch.

  Petra Schönfelder (Uni. Vienna)

  Welcome to Team Sternwarte!

  We will have an introduction from our new institute co-ordinator and discuss our wishes for Team Sternwarte in this coming year.
• 23.01.2026 - Public Presentation of Dissertation Projects (FÖP)

  Janus Brink
  Optimising spectroscopic performance at the ELT

  Michelangelo Pantaleoni Gonzalez
  Massive stars and the interstellar medium in the context of the local Milky Way

  Louis Müller
  Interior Outgassing and Dynamo Evolution of Earth, Venus, and Mars

  Anuja Raorane
  Influence of non-thermal escape processess on the evolution of early Earth, Mars, and Venus
• 16.01.2026 - Lukas Winkler (Uni. Vienna) & Manuel Guedel (Uni. Vienna)

  Lukas Winkler (Uni. Vienna)

  Scaling Differentiable Simulations in Cosmology to Multiple GPUs

  A fundamental question in cosmology is how the observed large-scale structure, the cosmic web, formed from primordial perturbations. With ongoing and upcoming surveys like Euclid, LSST and DESI mapping tens of billions of galaxies, these observations allow us to solve the inverse problem of inferring cosmological parameters, models and initial conditions. One important component of this effort are fast GPU-based simulations that model large-scale structure formation using only a small number of timesteps. However, fitting the vast fields of view of galaxy surveys into simulation boxes while resolving small scales needs large resolutions whose memory footprint requires distributing the computation across many GPUs. Another important ingredient is automatic differentiation, which allows efficient computation of gradients of the simulation output with respect to the parameters and the initial noise field. Sampling from the very high-dimensional parameter space of possible initial conditions is only feasible to converge when using gradient-based inference methods like Hamiltonian Monte Carlo (HMC). On top of that, gradients also allow us to efficiently determine which parameterizations, for example for timestep spacing, optimally reproduce simulations run with more timesteps.

  Manuel Guedel (Uni. Vienna)

  Shockingly hot and shockingly cool(ing): A fresh look at the environment of DG Tau

  DG Tau is a single Young Stellar Object young enough to combine features common to embedded protostars and more evolved, optically revealed classical T Tauri stars, itself not being subject to substantial extinction. This transition object is therefore a key target to understand accretion and ejection processes. It features a Keplerian disk with a hot, water-rich and strongly variable inner region, relics of a non-Keplerian envelope, accretion streamers, and most prominently a system of co-axial molecular, atomic, and ionized disk winds over a wide range of temperatures and velocities. The most extreme winds form a high-velocity bipolar jet system detected almost down to the disk surface at radio, infrared, optical, UV and surprisingly even X-ray wavelengths. New JWST/MIRI observations reveal very strong infrared forbidden lines for which I will propose a direct link to the ~4 MK X-ray emitting plasma jet via shock heating and cooling. If successful, such a model will reveal more about the inner workings of the jet. I will discuss shock models that involve collisional and photoionization, shock self-radiation, recombination and charge exchange that are necessarily progressing out of collisional ionization equilibrium and therefore need to be evolved iteratively in time; I will address some diagnostic power of these models.
• 09.01.2026 - Stefan Meingast (Uni. Vienna) & Alena Rottensteiner (Uni. Vienna)

  Stefan Meingast (Uni. Vienna)

  Mapping Interstellar Water Ice with Broadband Photometry

  Interstellar ices are a key ingredient of the cold, dense interstellar medium and are closely linked to the chemistry and evolution of molecular clouds and star-forming regions. Observationally, water ice is most directly traced by the broad absorption feature near 3 microns, but obtaining spectra at these wavelengths for large numbers of background stars is expensive and often limited in sky coverage. In this talk I present the ice color excess method (ICE), a photometric approach that estimates the peak optical depth of the 3 micron feature using widely available infrared broadband measurements. Building on the logic of near-infrared dust color-excess techniques, ICE isolates the additional extinction component introduced by icy grain mantles. I then describe an empirical calibration of the peak optical depth versus observational using a curated literature sample of background stars with spectroscopically measured optical depths. The calibration shows a remarkably tight correlation, demonstrating that broadband photometry can recover meaningful ice optical depths for individual lines of sight. Finally, I discuss how this technique can scale to large archival catalogs to produce spatially resolved ice maps, complementing spectroscopic studies with JWST and SPHEREx and enabling new constraints on the environmental dependence of ice formation and evolution on cloud and Galactic scales.

  Alena Rottensteiner (Uni. Vienna)

  Kinematics of young stellar objects in NGC 2024 based on infrared proper motions

  The most recently formed young stellar objects (YSOs) in active star forming regions are excellent tracers of their parent cloud motion. Their positions and dynamics provide insight into cluster formation and constrain kinematic decoupling timescales between stars and gas. However, because of their strong extinction and young age, embedded YSOs are mainly visible at infrared wavelengths and thus absent from astrometric surveys such as Gaia. We measured the proper motions of 6,769 sources toward the NGC 2024 cluster in the Flame Nebula using multi-epoch near-infrared observations from three ESO public surveys: VISIONS, VHS, and the VISTA/VIRCAM science verification program. Cross-validation of our results with Gaia using optically visible stars shows excellent agreement, with uncertainties on the same order of magnitude. For 362 YSO candidates identified from the literature, we derived proper motions on the order of <5 mas/yr with mean measurement uncertainties of ~0.22 mas/yr. This is the first homogeneous proper motion measurement of this quality for more than half of these stars. For Class I and flat-spectrum sources, our results provide a >13-fold increase in available proper motion measurements. We analyzed the positional and kinematic differences between YSO classes and confirmed a previously reported inside-out age segregation from younger to older stars, likely driven by an outward movement of older stars. No evidence of prolonged hierarchical assembly was found. Instead, the results support a rapid (<1 Myr) cluster collapse. This scenario also accounts for the observed slightly higher 1D velocity dispersion of Class I sources relative to Class flat objects. YSO radial velocities generally align with the gas velocities measured from 12CO(3-2), HNC(1-0), HCN(1-0), and show a weaker correlation with N_2H+(1-0). Some Class II and III objects appear to be already decoupling.
• 19.12.2025 - Efrem Maconi (Uni. Vienna) & The West Dome Team

  Efrem Maconi (Uni. Vienna)

  The late Miocene Beryllium-10 anomaly and the possibility of a supernova

  As the Earth and the other planets orbit around the Sun, the Solar System itself revolves around the center of the Milky Way, which is far from being a static and homogeneous environment. This constantly evolving environment, combined with the Sun’s peculiar velocity relative to the average velocity of the surrounding gas and stars, causes the Solar System to pass through diverse Galactic regions and occasionally come into the vicinity of supernova events. Recently, a Beryllium-10 anomaly has been identified in multiple ferromanganese crusts from the central and northern Pacific deep ocean. The anomaly spans the period from 9 to 11.5 Myr ago (Late Miocene), peaking around 10 Myr ago. Its origin remains uncertain: it may be terrestrial, or it could be related to an astrophysical event, such as a temporary increase in the Galactic cosmic-ray flux triggered by a nearby supernova. Interestingly, during this period the Solar System was leaving behind the active Orion star forming region. In this talk, I will present the observed Beryllium-10 anomaly and discuss the possibility that it was caused by a supernova, whose progenitor may have belonged to one of a few candidate clusters we identified.

  The West Dome Team: Peter Sterzinger, Hans Jasicek, Michael Grünanger, Andreas Kreutzer & Benjamin Werner

  Introducing the West Dome Team

  Next year, the West Dome 12“ Clark Refractor of the Vienna University Observatory celebrates its 150th anniversary. The telescope (est. 1876) still retains its original mechanics and high quality optics. For over 50 years, this historic and valuable instrument has been operated by a group of experienced amateurs. Today, several restoration and repair projects are necessary (e.g. for the tube assembly, finderscope and mounting) for a variety of reasons (e.g. damage, dirt, corroded parts). All of this work is carried out thanks to the initiative of the West Dome group. In this talk, we will introduce ourselves and describe our work in the West Dome.
• 05.12.2025 - Simon Schleich (Uni. Vienna) & Anuja Raorane (Uni. Vienna)

  Simon Schleich (Uni. Vienna)

  How much do you trust this atmosphere? Sensitivity of atmospheric retrievals to perturbations in data

  The James Webb Space Telescope (JWST) is providing us with exoplanet atmospheric spectra of unprecedented quality. This improved data presents new challenges in retrieving exo-atmospheric properties. One of these is determining the reliability of atmospheric signals from observations. Reliable signal extraction is crucial for robust atmospheric characterisation. I will present an investigation into the impact of small-scale variations in spectroscopic data on the retrieval of exoplanetary atmospheric properties, using the hot Jupiter WASP-39 b as a case study. We compared results from homogenised atmospheric retrievals performed on three transmission spectra, all produced with the same data reduction pipeline. The resulting parameter estimates can be classified into several groups, based on their stability under perturbations of the data. These findings underscore the importance of assessing the stability and sensitivity of atmospheric parameter inferences. Stable, robust frameworks are essential for reliable population-level characterisation of exoplanetary systems.

   

  Anuja Raorane (Uni. Vienna)

  Non-thermal Escape of Atmospheres

  The three rocky planets of our Solar System, Earth, Venus, and Mars, each once had the potential to sustain habitable conditions, yet today only Earth remains habitable. Planetary habitability is closely linked to the composition and surface pressure of an atmosphere, both of which are significantly influenced by atmospheric escape processes. Among these, non-thermal escape plays a key role and is primarily driven by interactions between a planet’s upper atmosphere (magnetosphere) and the solar (stellar) wind.

  Today, atmospheric loss from all three terrestrial planets is dominated by non-thermal escape processes. These mechanisms differ significantly from one planet to another, as they depend sensitively on the planet’s magnetic state and the level of solar activity. This makes studying them challenging. In this seminar, I will focus on key non-thermal escape processes, namely, solar wind charge exchange and polar outflow on Earth, and ion pickup on Venus. While present-day escape rates on Earth, Venus, and Mars are too low to substantially cause thinning of atmosphere, these processes were likely far more efficient earlier in Solar System history. Their cumulative effects may have played an important role in shaping the evolution, composition, and climate of the rocky planets.
• 28.11.2025 - Sylvia Ploeckinger (Uni.Vienna) & Janus Brink (Uni. Vienna)

  Sylvia Ploeckinger (Uni.Vienna)

  The first results from the COLIBRE project

  The COLIBRE project (http://colibre-simulations.org) is a brand-new (Schaye et al. 2025, arXiv:2508.21126) large cosmological simulation project. The flagship simulations include cosmological cubic volumes with side lengths of 400 Mpc and 200 Mpc resolved with a particle mass (dark matter and baryons) of 10^7 and 10^6 solar masses, respectively, as well as smaller volumes (25, 50, and in a second stage 100 Mpc) with a particle mass of 10^5 solar masses. I will present the first results from the COLIBRE project, which includes the evolution of the galaxy stellar mass function between redshifts 0 and 17, and compare the agreement to observations to previous simulation projects, such as EAGLE, IllustrisTNG, and Firebox. 

  Janus Brink (Uni. Vienna)

  A SALT road travelled - my journey in astronomical instrumentation development

  As I "recently" joined the Institute I would like to use this talk to introduce myself, but more importantly introduce my previous place of work and illustrate how it may be of scientific relevance to you! Without giving too much away here, my talk will include a bit of background on SALT, discuss my involvement in a number of projects there over the last two decades and highlight the instrument and science capabilities of the facility.  If your research involves solar system, exoplanetary, galactic, extra-galactic or time-domain observational astronomy there may well be collaboration opportunities to explore!
• 21.11.2025 - Michael Cecil (MPIA) & Werner Weiss (Uni. Vienna)

  Michael Cecil (MPIA)

  Structure, Evolution and (In)stability of the inner regions of protoplanetary disks

  The inner protoplanetary disk is the cradle of the terrestrial planets in our Solar System, as well as a large number of exoplanets that have been detected to date. The small spatial scales and the conglomeration of numerous physical processes pose extraordinary challenges to studying these inner regions and the origin of planets close to their host star from both observational and modelling perspectives. We intend to put several puzzle-pieces into place by employing radiation-hydrodynamic simulations of these elusive regions to investigate their evolution and long-term stability. Our models show the emergence of large-scale instability mechanisms, that periodically reshape the structure of the inner disk and lead to observable variability of accretion onto the central star on various scales. I will discuss the physical foundations of the inner disk structure and explore the origins of these instabilities together with the potential consequences for the formation of planets or planetesimals in the inner disk. In addition to producing a variety of accretion burst signatures, such numerical simulations represent another step forward in sorting out the complexities of the evolution of planetary birthplaces.

  Werner Weiss (Uni. Vienna)

  The BRITE-Constellation

  UniBRITE and BRITE-Austria are the first satellites listed for Austria in the UN space register. UniBRITE was funded by the Science-Ministry in 2005 as part of a program dedicated to develop Austrian Universities. A  year later, a joint proposal of the Technical University of Graz and the University of Vienna was accepted by the FFG, which triggered BRITE-Austria. These two BRIght Target Explorer cubesats (BRITE) triggered a cooperation with Canda and Poland, which resulted in an ensemble of six similar cubesats devoted to astrophysics, in particular to asteroseismology. This ensemble is known as BRITE-Constellation.

  Cubesats were originally intended as testing tools for technical components in space and as a learning tool for students. But BRITE cubesats are the first, which explicitly were devoted to astrophysical research. Specified for a lifetime of 2 years, data are still produced after 10 years of operation and resulted meanwhile in more then 200 papers. Spectacular research highlights are, e.g., observations of a nova with high time resolution, starting before it became visible from ground, or discovering the onset of pulsation during periastron passages of very eccentric binaries. Another first and highlight is a new method for determining the stellar mass' of RG stars from the granulation signal which is buried in their Fourier spectrum.
• 14.11.2025 - Ivan Stanković (Uni. Vienna) & Sudeshna Boro Saikia (Uni. Vienna)

  Ivan Stanković (Uni. Vienna)

  How does chemistry control exoplanet atmospheric stability?

  Exoplanet atmospheres are very chemically diverse. Parameters like metallicity and the C/O ratio are often used to describe them, but while these work relatively well for hydrogen-rich gas giants, they are not suited for describing rocky planets. To identify better metrics and explore which compositions are actually stable and which are more susceptible to loss, I investigate how different elemental mixtures behave over long timescales against thermal escape using our atmospheric model, Kompot.

  I construct a grid of upper atmospheric compositions for an Earth-like planet by varying the amounts of H, C, N, O, and S. This extends previous applications of our model, which focused on CO2-N2 atmospheres, to a broader chemical space.

  I will show that atmospheric lifetime depends strongly on the bulk elemental composition: it increases with oxygen and carbon content, but decreases with the amount of nitrogen. In terms of elemental ratios, the mass loss is correlated with H/O, H/S, C/O, and N/O, in that order. Sulfur shows little effect on its own, while the role of hydrogen requires further exploration, as the current model set only covers low-H cases.

  Sudeshna Boro Saikia (Uni. Vienna)

  Titan as a laboratory for exoplanet chemistry

  Saturn’s moon Titan is the only other body in the solar system with surface liquids and a thick atmosphere rich in organic compounds. In addition to its huge astrobiological potential, it also possesses the only nitrogen-rich atmosphere besides Earth. Understanding its complex atmospheric composition is essential for identifying similar chemical signatures in distant exoplanets. In this talk, I will discuss simulations of the thermal and chemical structure of Titan's upper atmosphere using the Kompot code, and provide observational context from Cassini and ground-based data. I will also highlight how self-consistent modeling helps resolve current degeneracies between observations and theory, offering a more robust framework for interpreting atmospheric chemistry in the Solar System and beyond.
• 07.11.2025 - Christoph Saulder (MPE) & Chiara Buttitta (INAF Naples)

  Christoph Saulder (MPE)

  Cosmology with the DESI peculiar velocity survey

  While the main science goal of DESI is to measure the expansion rate of the universe using Baryon Acoustic Oscillations, the incredible amount of spectra collected by the instrument allows for additional cosmological measurements using other probes. The DESI peculiar velocity survey derives peculiar velocities using the fundamental plane and Tully-Fisher relation and it will provide the largest peculiar velocity sample every observed. This unique and vast dataset will allow us to measure the strength of gravity via the growth rate of structure at unprecedented precision. I will present the results from the early DESI data, as well as provide an outlook on the upcoming DESI DR1 analysis of peculiar velocity and the scope of DESI DR2 peculiar velocity key project.

  Chiara Buttitta (INAF - Osservatorio Astronomico di Capodimonte, Naples)

  Probing the limits of spectroscopy in the low-surface brightness Universe with LEWIS

  In the standard cosmological framework of ΛCDM, low-surface brightness (LSB) galaxies are the building blocks of the Universe. Ultra-diffuse galaxies (UDGs) play a crucial role. This class of extreme galaxies have a central surface brightness fainter than μ₀ ≥ 24 arcsec² and an effective radius larger than Re ≥ 1.5 kpc, thus can be considered as the extreme LSB tail of the size-luminosity distribution of the dwarf galaxies population. Due to their extremely faint and diffuse nature, collecting deep spectroscopic data is challenging and time-consuming, and only a few dozen UDGs have been studied with spectroscopy. In this context, the LEWIS project (Looking into the faintEst WIth MUSE, P.I. Enrica Iodice) promises to revolutionise the scientific panorama of the UDGs doubling the number of spectroscopically studied UDGs to date. It aims to study for the first time the structural properties of a nearly complete sample of UDGs in the Hydra I cluster of galaxies. In this contribution, I would like to present the recent groundbreaking results we achieved with LEWIS, highlighting the challenges we faced in the extraction of structural properties of these extremely faint objects.

   

   
• 31.10.2025 - Turan Ali

  Turan Ali

  Storytelling for Scientists

  Storytelling is the only way we can profoundly communicate as humans. Often, when scientists try to communicate, they prioritise information-transfer over storytelling, treating their “audience” as information processors, not storytelling creatures. If information is embedded in great stories, integral to the plot, the story is understood and the information remembered. Information delivered without story is quickly lost.

  In this taster session, Turan Ali, producer/writer/director of BBC drama, on-stage storyteller and stand-up comedian, who is a former biologist, introduces the major elements of story theory and explores at which points in a story learning, persuasion and memorising happen. He touches on how to harness the intrinsic power of stories for any subject and also explores the role of emotion and symbols in storytelling, and how not to leave a story’s impact to chance.

  Lastly, the myriad ways that stories can be delivered will be summarised, pinpointing general principles of which formats of storytelling are suitable for what sort of stories and goals. Choosing the right or wrong way to tell your story will make or break its impact. The amount of information in your story will dictate which formats (or combinations) could be used to tell the story effectively, and which formats (or combinations) would kill the story. Powerful communication is achieved by consciously combining story structure, information-quantity and appropriate format(s). Yes, storytelling is rapidly becoming a precise science with provable, measurable, cause and effect.

  We will touch on all these elements, in this lively, participatory taster session.
• 17.10.2025 - Yannic Pietschke (Uni. Heidelberg) & Laurane Fréour (Uni. Vienna)

  Yannic Pietschke

  Reconstructing Reionization with 21cm Summaries and Galaxy Synergies

  The Square Kilometre Array (SKA) enables precise measurements of 21cm fluctuations that trace ionization, temperature, and density fluctuations of the intergalactic medium. However, directly reconstructing the timeline of reionization in terms of the evolving neutral hydrogen fraction remains challenging due to the highly non-Gaussian nature and thus intractable likelihood of the 21cm signal. In this talk, I will introduce EoRFlow, a simulation-based inference (SBI) framework that yields fast, unbiased posterior estimation of the $x_\mathrm{HI}$ evolution in narrow redshift slices, allowing for piecewise reconstruction of the global reionization history. To demonstrate the applicability of our method, we validate it on realistic mock datasets generated using the SKA-Low AA* telescope configuration, and demonstrate how the choice of summary statistics, from power spectra to network-learned features, impacts the accuracy and robustness of SBI. Finally, I will highlight the potential of combining SKA and galaxy survey data to unlock new insights into the epoch of reionization.

  Laurane Fréour

  Astronomers for Planet Earth, a grassroots movement of more than 2300 Volunteers

  Since its founding in 2019, Astronomers for Planet Earth (A4E) has been working to share the powerful view astronomers have of Earth. We, as astronomers, know how rare life on a planet is. We, as astronomers, know that there is no planet B. This perspective not only helps communicate the urgency of the climate crisis, but also reminds us of what is at stake. 

  We focus on outreach and education, creating and sharing tools to help communicate and teach on climate change. We also foster a strong sense of community among members, united by shared values around justice, sustainability, and the preservation of life on Earth, and driven by our passion for astronomy.

  In this talk, I will explain how A4E is structured. I will highlight recent projects and milestones, and explore how collaborative efforts can amplify impact. Finally, I will suggest concrete ways that individuals, whether students, astronomers, or institutions, can get involved. 
• 10.10.2025 - Alvaro Hacar (Uni. Vienna) & Emily Hunt (Uni. Vienna)

  Alvaro Hacar

  On the origin of clusters within the filamentary ISM

  Recent ALMA observations indicate that young proto-clusters originate at the intersection point of large-scale filaments in the so-called hub-filaments systems (HFS). While formed as part of the filamentary structure of the ISM, the properties of these HFS largely depart from their parental filaments in terms of mass, size, column density, stability, and accretion rates. During my talk I will show how the formation and properties of these HFS, and thus of stellar clusters, can be explained by a geometric phase-transition between filamentary and spheroidal gas configurations during the assembly of these HFS.

  Emily Hunt

  Twitter is dead. How can we do better for networking and outreach?

  Twitter spent ten years as the de facto online platform for astronomy networking and outreach. However, semi-recent events have seen it devolve into a politicized and ineffective platform for science communication and networking. The loss of Twitter has shown how fleeting online spaces can be. It begs the question: can we do better, or are astronomers doomed to always have their online homes tied to the whims of a billionaire?

  In this talk, I will present The Astrosky Ecosystem: an open source project to build independent social media infrastructure with the AT Protocol, the social media protocol that powers Bluesky (a prominent Twitter challenger). After discussing the basics of the AT Protocol, I will discuss what our project does, and how we are building ways for the astronomy community to have full, independent online sovereignty of its data. I will also discuss how you can use Bluesky and our tools to build an online network.

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• 04.07.2025 - Sebastian Grandis (Uni Innsbruck) & Christian Maier (Uni Wien)

  Sebastian Grandis (Uni Innsbruck)

  Weak lensing calibrated cluster number counts

  We will showcase how to find galaxy clusters in X-ray, millimeter, and optical data based on recent results from the South Pole Telescope Collaboration and the eROSITA consortium. We then discuss how weak gravitational lensing allows us to determine the mass scale of the selected clusters, and how the number density of clusters as a function of mass and redshift gives us essential information about the structure of the Cosmos. Our recent analyses show that clusters provide an accurate probe of the cosmological model, complementary and competitive with more established large-scale structure analyses like cosmic shear. We will give a short outlook into upcoming multi-wavelength observing campaigns and their implications for cluster cosmology.

  Christian Maier (Uni Wien)

  The BLOBs: Enigmatic Gigantic Diffuse Ionized Gas Structures in a Cluster of Galaxies near Cosmic Noon

  I will report a new discovery near cosmic noon using MUSE IFU data: three gigantic diffuse ionized gas structures detected as oxygen ionized gas in a high redshift cluster of galaxies. The source of ionization of one of the gaseous structures (1145 square kpc) which displays two prominent filamentary patterns seems to be an active galactic nuclei (AGN). The other two diffuse ionized oxygen gaseous structures (571 square kpc and 1270 square kpc, respectively) are more enigmatic, with no AGN in their vicinity, and especially because they do not have any counterparts in the optical/near-infrared data, but they lie between the stellar components of (passive) cluster galaxies. Ram-pressure stripping of photo-ionized gas, shocks and/or excitation by fast-ionizing particles from the surrounding hot gas could be an explanation. Additionally, the galaxy velocity distribution in this high redshift cluster is bimodal indicating that the cluster is unlikely to be fully virialized, and that a recent merging event is also possibly linked to the two observed extended diffuse ionized gas structures between galaxies. Thus, two of these Blobs remain enigmatic - no clear evidence for their photoionization source. To unearth the truth about this enigmatic finding new simulations of the warm (10000K) gas in the early-phases of clusters at high redshifts are needed.
• 27.06.2025 - Christian Albert (Uni Wien)

  At this special institute seminar, we'll hear from Christian Albert. Christian was Head of the Human Resources Department at the University of Vienna for ten years and has been a conflict consultant at the University of Vienna since 2006. In his role as conflict consultant, he offers all employees free advice and support on problems related to their work in the form of individual counseling, mediation or team counseling.
• 20.06.2025 - FÖP Public Presentations

  • Shivam Joshi: Debris Disc Modeling in Multiple Wavelengths
  • Ivan Stankovic: Influence of Initial Chemical Conditions on Exoplanetary Atmospheric Properties, Mass Loss Rates and Lifetimes
  • Nils-Martin Robeling: Atmospheric Photochemistry for Exoplanetary Spectra Using the Kompot Code

    

  Find all FÖP public presentations of the faculty here.
• 06.06.2025 - Max Zimmermann (Uni Wien) & Marko Mecina (Uni Wien)

  Max Zimmermann (Uni Wien)

  Terrestrial planet formation considering various binary star configurations

  To date there have been already 730 binary star systems discovered, which inhabit at least one planet. Most studies that have investigated the late stage of terrestrial planet formation in binary stars considered planar configurations, which might be accurate for tight binary stars. However, for wide binary stars it is assumed, that the inclination between the two stars is randomly distributed. Thus, a possible misalignment between the planet forming disk and the secondary star has to be taken into account. We investigate the evolution of a planetesimal-planetary embryos disks, consisting of 2000 planetesimals and 25 planetary embryos, in various binary star configurations. In the late stage of terrestrial planet formation (after the gas phase), the gravitational interactions of the disk objects dominate. To study all the gravitational interactions in a reasonable time, we apply our GPU parallelized N-body code GANBISS and compute the dynamical evolution of the disks, where the planetary embryos grow to terrstrial-like planets via perfect inelastic collisions. As collisions among planetary embryos and planetesimals have in reality a more diverse outcome, we perform post-processing analysis of all collisions that occur during the N-body simulations, by making use of an analytic model.

  Our full N-body approach of embryo-planetesimal disks indicate mainly two results in the dynamical evolution of the disk: (i) In misaligned configurations planetary embryos undergo an inward migration due to dynamical friction and collisions, leaving space in the outer part of the disk for an asteroid-belt like structure. (ii) The planetary embryos align onto the inclination of the secondary with small variations due to dynamical friction and collisions, except in highly inclined configurations (inclination of the secondary i_b = 45°) in the outer regions of the disk, where the variations of the inclination of the embryos are larger. Comparing the collision outcomes between planar and inclined configurations, we find a strong increase of the destructive collisions.

  Marko Mecina (Uni Wien)

  Keep SMILEing - Developing software for a space mission

  SMILE is an ESA/CAS joint space mission to be launched in early 2026, intended to study the interface between the solar wind and Earth's magnetosphere. Our group is providing the application software for the SXI instrument, which aims to obtain a global x-ray view of the interaction region. I will briefly present the science objectives and instrumentation, and share the good, the bad, and the ugly of the development process during the past years.
• 23.05.2025 - Fabian Haberhauer (Uni Wien) & Cloudflight

  Fabian Haberhauer (Uni Wien)

  Simplified ELT IFU simulations with ScopeSim

  The general-purpose ELT (and more) observations simulation engine "ScopeSim" continues to evolve. In this brief progress update, I will present the new "simple IFU" mode recently added to the simulator and give a general update of new features and improvements as well as ongoing challenges. I am going to show some example simulations and explain some of the inner workings of the code. Finally, I will give an outlook into the planned development over the next few months.

  Cloudflight: Manuel Lanzinger, Andreas Hangler, Arthur Lehner, Michael Aspetsberger

  Algorithm analysis and optimization

  Many scientific related projects share the same challenges: the current solution, while functional for small-scale cases, struggles with performance, scalability, and maintainability in real-world scenarios. It often relies on third-party algorithms that are often a poor fit and hard to integrate effectively. In long-lasting projects and over time, the system's logic tends to become overly complex, poorly documented, and reliant on ad-hoc implementations, making it difficult to reason about, especially in areas involving concurrency, caching, and incremental processing. While it handles most common cases adequately, it fails to address edge cases comprehensively. Overcoming these issues requires a redesign focused on performance efficiency, modular and well-documented architecture, domain-specific algorithmic solutions, and formal verification or testing strategies to ensure reliability in edge scenarios. To address correctness challenges, the solutions should emphasize consistent conceptual modeling—clarifying definitions and ensuring alignment across classification schemes. Code correctness is reinforced by tackling concurrency issues and explicitly handling edge cases, as surfaced in contexts like competitive coding scenarios. For improved efficiency, such approach targets performance hotspots, leverages intelligent caching strategies, optimizes data access patterns, and employs rapid prototyping to identify and implement quick wins. Together, these strategies form a foundation for building a robust, high-performance, and maintainable system – independent from remotely sensed data being retrieved and processed on earth or space. In this seminar contribution, Cloudflight team members show exemplary how algorithm analysis and optimization could enable researchers to e.g., apply algorithms for retrieval of atmosphere and surface properties from a local to a global scale or reducing Fortran based data fusion times for identifying biomass anomalies, NRT phenology, and rangeland performance from different Copernicus data. Such performance and consistency increase were achieved by understanding scientific algorithms and their applications, making them both performant and efficient.
• 16.05.2025 - Gwenaël Van Looveren (Uni Wien) & Evelyn Macdonald (Uni Wien)

  Gwenaël Van Looveren (Uni Wien)

  Where to look for atmospheres

  We all want time on the fancy large telescopes, so we must ensure that we decide wisely what to do with the time that is given to us. In the search for planets similar to Earth, we can do this by determining what kind of atmospheres we expect to see, or whether we expect certain planets to hold onto atmospheres at all. In this talk, we will have a look at different combinations of stellar and planetary parameters to determine where we best focus our search for Earth-like planets.

  Evelyn Macdonald (Uni Wien)

  Climates and spectra of Earth-like planets

  Although there are nearly 6000 confirmed exoplanets, Earth is the only planet known to be habitable or inhabited. Our ability to observe Earth-like exoplanets is very limited with current instruments, so numerical simulations are an essential tool for understanding their climates and interpreting observations of their atmospheres. In this talk, I will use a 3D climate model to discuss some key factors that contribute to an Earth-like planet’s climate, including rotation speed, atmospheric composition, land cover, and stellar type. I will also discuss the possible impacts of these factors on observations with current and next-generation instruments.
• 09.05.2025 - Shivam Joshi (Uni. Wien) & Nicole Pawellek (Uni. Wien)

  Shivam Joshi (Uni. Wien)

  Modeling debris disc of HD 131488: Bringing together scattered light and thermal emission.

  Debris disks are dusty remnants of planet formation, shaped by collisions, radiation pressure, and sometimes residual gas. Modeling them is often tedious due to complex grain dynamics and the need to match both scattered light and thermal emission data. HD 131488 is a young A-type star, around 10 million years old—an age where disks transition from gas-rich protoplanetary to gas-poor debris systems. Melis et al. (2013) found it hosts both a warm inner dust belt and a cooler outer one, but the strong mid-infrared excess remains unexplained, pointing to a complex inner structure. Moór et al. (2017) detected molecular gas, suggesting it's a hybrid disk rather than a typical debris system. ALMA observations later revealed a bright emission ring at 89 AU with additional substructures, hinting at a multi-ringed outer disk. Pawellek et al. (2024) showed that including gas drag is essential to reproduce the observations, confirming that gas still plays a role in defining disc dynamics and structure. I’m currently modeling both the scattered light and thermal emission using the latest high-resolution data, aiming to build a more robust and self-consistent picture of the system.

  Nicole Pawellek (Uni. Wien)

  The population of debris discs

  Debris discs are – similar to planets – the outcome of planet formation processes. Studying the evolution of such discs gives us insight into our own Solar system and thus helps us to understand where we come from. Using a survey performed by the Herschel Space Telescope we found that only ~20 per cent of old nearby field stars possess detectable debris discs. In this talk I will address the question on how a population of debris discs might look like including the ~80 per cent of stars without detectable discs. Our population model indicates that there might be two sorts of discs – one that contains large planetesimals and the other that only contains small planetesimals. Hence, the question of whether planetesimals are born big or small might be answered by both.
• 02.05.2025 - Stefanie Reiter (Uni. Wien) & Vlad Rastau (Uni. Wien)

  Stefanie Reiter (Uni. Wien)

  How can cosmological simulations inform the recovery of stellar orbit distributions of galaxies?

  Orbit-based dynamical modelling is a powerful tool which can be used to infer formation histories of galaxies. We use a triaxial implementation of the Schwarzschild method to recover the internal structure of spectroscopically observed galaxies and to disentangle individual dynamical components. To inform the analysis of the resulting orbit distributions, I am working with TNG50, a new generation of cosmological simulations with high enough resolution to analyse the stellar components of individual simulated galaxies in a similar way as in the dynamical models of observed galaxies. Simulated galaxies come with the advantage of known merger histories, allowing us to investigate potential links between the physical properties of past mergers and the present-day orbit distributions. Additionally, we aim to use the orbit distributions of TNG50 galaxies to construct physically motivated priors to inform our dynamical modelling, improving the uncertainty quantification in the orbit models.

  Vlad Rastau (Uni. Wien)

  How close are we to understanding AGB winds?

  AGB stars have complex chemistries and experience significant winds, which ultimately cause the stellar atmosphere to dissipate. So far, studies split these objects in two main categories, oxygen- and carbon-rich, each group having its own main characteristics. However, we are still trying to understand how the winds of such stars evolve based on the different chemistries, namely the degree to which this plays a role in the ejection of stellar matter into the interstellar medium and the subsequent evolution of low-mass stars. In this talk I will summarise some of the main ideas we have surrounding the evolution of AGB winds and show some of the ongoing observational and modelling work aimed at understanding this phenomenon.
• 24.04.2025 - Thomas Flöss (Uni. Wien) & Rebekka Coles-Bieri (UZH Zurich)

  Thomas Flöss (Uni. Wien)
  
  Inflation as a Cosmological Collider
  
  The hot big bang is presumed to have been preceded by a brief phase of rapidly accelerated expansion, known as cosmic inflation. Besides explaining the observed homogeneity, isotropy and flatness of the universe, it also naturally generates tiny density fluctuations that serve as the seeds of structure formation. I will discuss how inflation could have acted as a cosmological particle collider, at an energy scale far beyond that of terrestrial particle collider experiments, providing a unique window into high-energy physics. I will go on to discuss some prospects for studying the cosmological collider using cosmic structures.
  
  Rebekka Coles-Bieri (UZH Zurich)
  
  ARRAKIHS Mission Overview
  
  ARRAKIHS (Analysis of Resolved Remnants of Accreted galaxies as a Key Instrument for Halo Surveys) is ESA’s second F-class mission, designed to explore the low surface brightness universe beyond the Local Group. Its core objective is to constrain the nature of dark matter and the role of baryonic physics by detecting and characterizing faint stellar structures—such as tidal streams, shells, and diffuse halos—around 75 Milky Way analogues. These features preserve the imprints of hierarchical galaxy assembly and serve as sensitive probes of the underlying gravitational potential.
  
  To achieve this, ARRAKIHS will conduct deep, simultaneous visible and infrared imaging from space, reaching unprecedented low surface brightness limits. The mission’s observational requirements—including the field of view and dithering strategy—are directly informed by a suite of simulations that predict the extent, frequency, and morphology of these faint structures.
  
  In this talk, I will present the scientific goals of the mission and the simulation efforts that support and motivate the survey design. I will also highlight the structure of the international consortium and outline the timeline toward launch in 2030.
• 11.04.2025 - Cameren Swiggum (Uni. Wien) & Francesca Bonanomi (Uni. Wien)

  Cameren Swiggum (Uni. Wien)

  Rewinding 70 million years of nearby Star Formation with Gaia

  Gaia DR3 has revolutionized our understanding of the solar neighborhood, providing precise astrometry and spectroscopy to reconstruct the 3D history of local star formation. In this talk, I will present our evolving view of how star clusters and associations have formed within one kiloparsec of the Sun. We can now visualize the evolution of past star-forming complexes, mapping when and where star formation occurred within them over tens of millions of years. By integrating the orbits of young clusters backward in time, we uncover clear formation patterns driven by stellar feedback on hundred-parsec scales. This process of sequential star formation suggests that many of today’s youngest star-forming regions—such as Sco-Cen, Taurus, and Vela—likely emerged as a consequence of more massive complexes that preceded them. High-resolution 3D interstellar dust maps further reveal that large cavities in the ISM, shaped by clustered supernovae, are often occupied by the young clusters that formed from these past complexes. Additionally, the bulk motions of these previous complexes are not random; rather, they are dynamically linked to well-known kinematic structures in the solar neighborhood, namely the Pleiades and Coma Berenices moving groups. This connection suggests that the Galaxy’s non-axisymmetric forces, such as spiral arms, have played a role in shaping both the formation and motion of these complexes. With Gaia DR4, its enhanced kinematic precision and potential to uncover more lower-mass clusters will refine our view of the recent star formation history while also extending our ability to trace local star formation further back in time and farther from the Sun. This will reveal deeper connections between past and present star-forming complexes and their role within the broader dynamics of the Milky Way.

  Francesca Bonanomi (Uni. Wien)

  The formation of fibers in molecular clouds

  The presence of fibers in N2H+(1-0) has been detected above ~10^5 cm^-3 (~10^22 cm^-2) in several star-forming (SF) regions. These fibers are the velocity-coherent substructures of pc-scale filaments characterized by subsonic motion. The origin of these fibers is still under debate. In this work, we investigate how the diffuse and turbulent gas material connects to those dense fibers, charachterizing the environment where fibers formed. HNC(1-0), detected down to 5x10^21 cm^-2, becomes a key tool to probe this diffuse gas. We investigated the HNC(1-0) emission in a sample of 5 SF regions in Orion, part of the EMERGE Early ALMA Survey, observed at ~2000 au resolution. We have characterized the environment surrounding the fibers investigating of the diffuse gas kinematics, as velocity dispersion and turbulence regime. By exploring those gas properties in both low and high- mass SF regions we aim to investigate the origin of fibers in different environments.
• 04.04.2025 - Anne Hutter (Cosmic Dawn Center)

  Anne Hutter (Cosmic Dawn Center)

  Exploring variable stellar initial mass functions as an explanation for JWST's ultraviolet-bright z>10 galaxies

  JWST has revealed an unexpectedly high abundance of ultraviolet-bright z>10 galaxies, sparking discussions about the nature of star formation and the interstellar medium in the early universe. Which physical processes shaped their appearance? Do high gas densities enable feedback-free star formation, or does the nature and distribution of dust play a role? Is their star formation highly stochastic, or do they host a higher fraction of massive stars? We have used the Astraeus semi-numerical galaxy evolution and reionisation model to explore how different parameterisations of a variable stellar initial mass function (IMF) shape galactic scaling relations, the ultraviolet luminosity functions at z=5-15, and reionisation. In this talk, I will briefly review the proposed explanations for early ultraviolet-bright galaxies before focusing on how different variable IMFs affect the galaxy population. In particular, I will discuss what qualitative IMF dependence on galaxy properties is needed to explain z>10 JWST observations.
• 28.03.2025 - Sylvia Ploeckinger (Uni. Wien) & Efrem Maconi (Uni. Wien)

  Sylvia Ploeckinger (Uni. Wien)

  A sneak peek into the COLIBRE project

  The COLIBRE project - a large simulation project studying galaxy formation and evolution - is being completed at the moment and will be presented to the general public late Spring this year. The flagship simulations include cosmological cubic volumes with side lengths of 400 Mpc and 200 Mpc resolved with a particle mass (dark matter and baryons) of 10^7 and 10^6 solar masses, respectively, as well as smaller volumes (25, 50, and in a second stage 100 Mpc) with a particle mass of 10^5 solar masses. In this preview I will introduce the COLIBRE project, discuss the biggest improvements from previous simulation projects, such as EAGLE and IllustrisTNG, and show the first results. As the COLIBRE collaboration is currently inviting collaborators to use the COLIBRE data for various science projects, I will also outline the process to use the COLIBRE data already now.

  Efrem Maconi (Uni. Wien)

  
  Synthetic Faraday sky observed within a Local Bubble-like cavity

  
  Faraday rotation describes the change in the linear polarization angle of radiation passing through a magnetized plasma. The magnitude of this effect depends on the line-of-sight magnetic field component and the thermal electron density traversed by radiation - both key quantities for characterizing the Milky Way’s magnetic field. However, as the Solar System is within the Local Bubble, the impact of local structures on the Faraday signal might be underestimated. In this talk, I will present the synthetic Faraday sky as observed from the center of a Local Bubble-like cavity, selected within a magnetohydrodynamic simulation. I will discuss the imprint of the bubble walls on the Faraday signal and explore its actual origin in detail. Additionally, I will show the Faraday sky derived from diffuse polarized synchrotron radiation by Galactic cosmic ray electrons. I will conclude by emphasizing the role of upcoming Milky Way simulations in interpreting future high-resolution Faraday rotation maps.
• 21.03.2025 - Francisco Aros (Uni. Vienna) & Sebastian Hutschenreuter (Uni. Vienna)

  Francisco Aros (Uni. Vienna)

  Insights from the degree of energy equipartition in globular clusters.

  Two-body relaxation drives the dynamical evolution of Globular Clusters (GCs). As stars interact inside GCs, they exchange kinetic energy, making the clusters develop different degrees of energy equipartition. As new observations with HST and JWST bring high-quality kinematic and photometric data of stars in GCs down the faint end of the main sequence and out to multiple half-light radii, studying the degree of energy equipartition in GCs has become a new window into understanding their dynamical processes and evolution. In this talk, I will discuss how the observed degree of energy equipartition in GCs could provide insight into the presence of stellar-mass black holes and the mixing process in clusters with multiple populations.

  Sebastian Hutschenreuter (Uni. Vienna)

  Inferring the structure of the Galactic Magnetic Field

  The Galactic Magnetic Field (GMF) plays an important role in shaping the structure of the Milky Way by regulating fundamental processes such as star formation and the transport of charged particles in the interstellar medium (ISM). The GMF is shaped by the dynamic interplay of plasma and gravity, as well as stellar feedback. Understanding the GMF is not only fascinating in its own right but also essential for explaining extragalactic phenomena, particularly the Cosmic Microwave Background. Despite its significance, the three-dimensional structure of the GMF remains elusive. In my talk, I will showcase how we can map the GMF by employing modern statistical frameworks. Specifically, I will demonstrate the use of Faraday rotation to obtain direct estimates of the average GMF strength across the full sky, I will present a three-dimensional reconstruction of dust polarization source fields tracking the local GMF, and I will emphasize connections of these maps to the recent history of the local ISM.
• 14.03.2025 - Quentin Changeat (Uni. Groningen) & Oleg Savchenko (GRAPPA Institute)

  Quentin Changeat (Uni. Groningen)
  
  Interpretation of exoplanet atmospheres with space observatories.
  
  The characterization of exoplanets relies on precise observations from space-based telescopes, which provide crucial data on planetary atmospheres and their composition. Missions such as Hubble and JWST have already delivered high-quality spectroscopic data for hundreds of transiting and directly imaged exoplanets. In 2029, these observatories will be joined by Ariel, a dedicated ESA mission designed to study thousands of exoplanet atmospheres. Together, these missions will revolutionize the field, generating an unprecedented volume of high-quality data essential for identifying trends in exoplanet populations. In this talk, I will discuss how these observatories contribute to our understanding of exoplanetary systems, highlighting key discoveries as well as modern challenges in data reduction and atmospheric interpretation.
  
  Oleg Savchenko (GRAPPA Institute)
  
  Sequential simulation-based inference for cosmological initial conditions
  
  Knowledge of the primordial matter density field from which the present non-linear large-scale structure emerged is of fundamental importance for cosmology, as it contains an immense wealth of information about the physics, evolution, and initial conditions of the universe. Reconstructing this density field from galaxy survey data is a notoriously difficult task requiring advanced cosmological simulators and sophisticated statistical methods to explore a multi-million-dimensional parameter space. In this talk, I will discuss how simulation-based inference allows us to tackle this problem and obtain data-constrained realisations of the primordial dark matter density field in a simulation-efficient way for general non-differentiable simulators. In addition, I will describe how our method allows us to turn any initial conditions point estimator into a fast sampler, and our novel adaptive learning training strategy to simultaneously infer the initial conditions together with the cosmological parameters. (Mostly based on arxiv.org/abs/2502.03139)
• 21.02.2025 - Laura Scholz-Díaz (INAF - Osservatorio Astrofisico di Arcetri) & Graham Smith (Uni. Birmingham/Uni. Vienna)

  Laura Scholz-Díaz (INAF - Osservatorio Astrofisico di Arcetri)

  The impact of dark matter halos on the baryonic content of galaxies: Dynamical evidence from the CALIFA survey

  The interplay between the baryonic physics of galaxies and the assembly of dark matter halos is essential for understanding galaxy formation, but remains elusive to observations, which typically rely on indirect halo characterizations. In this talk, I will report direct observational evidence from the CALIFA survey showing that the baryonic properties of nearby galaxies -such as age, metallicity, star formation rate, morphology, stellar angular momentum- as well as the radial profiles and gradients of their stellar populations, are influenced by their host halos. Through detailed dynamical modeling of optical integral-field spectroscopic data, we found that for galaxies with similar stellar masses, these baryonic properties vary depending on their total enclosed mass (stars + dark matter). We demonstrate that total mass correlates with halo mass inferred from indirect methods, as well as in numerical simulations. Our findings indicate that dark matter halos play a key role in shaping the baryonic content of galaxies and suggest that the timing of halo formation could significantly impact observed galaxy properties.

  Graham Smith (Uni. Birmingham/Uni. Vienna)

  Adventures of a gravitational lenser in Vienna

  I will summarise some scientific highlights from my Winter Semester in Vienna. Of course gravitational lensing and Rubin/LSST will feature, but so too will hunting for extragalactic planets, and probing quantum physics with gravitational lensing in the Solar system. I will also summarise recent progress in Rubin/LSST on-sky commissioning, but sadly am not allowed to show any data. 

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• 24.01.2025 - Prem Kumar & Fabian Haberhauer (FÖP)

  Prem Kumar

  Connecting Present-day Galaxies and their Progenitors with Stellar Population-Dynamics

  This talk will present my PhD project, which investigates the evolution of galaxy orbital components (cold, warm, hot, and counter-rotating orbits) fromz~1 to z~0 . By combining high signal-to-noise LEGA-C spectra of approximately 3,000 galaxies with Schwarzschild orbit-superposition models and simulations, the project aims to reconstruct galaxy assembly histories, uncovering the intrinsic properties and formation pathways of these orbital structures.

   

  Fabian Haberhauer

  On the expected contribution of the ELT and its instruments to constrain the parameters of the origins of star formation in diverse environments
• 02.02.2024 - Sudeshna Boro Saikia

  Title: "On the connection between UV emission lines, atmospheric motions and stellar winds"
• 26.01.2024 - FÖP
• 12.01.2024 - Team Sternwarte

  Title: "New year's resolutions - Team Sternwarte"
• 15.12.2023 - Gwenaël Van Looveren

  Title: "To AI, or not to AI, that is the question"
• 01.12.2023 - Péter Ábrahám

  Title: "Fireworks during early stellar evolution: the eruptive phenomenon of newborn stars"
• 24.11.2023 - Kieran Leschinski

  Title: "Vienna at the ELT - starting the discussion for how to use our guaranteed observing time"
• 17.11.2023 - Nicole Pawellek

  Title: "A self-consistent multi-wavelength model for dust in debris discs"
• 10.11.2023 - Prashin Jethwa

  Title: "Modelling Non-Gaussianity in Galaxy Velocity Distributions"
• 03.11.2023 - Nicole Pawellek

  Title: "How to give better presentations"
• 27.10.2023 - Horst Foidl & Bodo Ziegler

  Horst Foidl - "A proposal to increase accuracy of cosmological observables"

  Bodo Ziegler - ÖGAA
• 13.10.2023 - Avinash Chaturvedi (Leibniz-Institut für Astrophysik Potsdam)

  Title: "A dynamical mass-map of the Fornax galaxy cluster"

  Abstract - The Fornax cluster provides an unparalleled opportunity to investigate the formation and evolution of early-type galaxies in a dense environment. Thanks to its proximity and building on a wealth of ancillary data, the Fornax cluster provides a unique chance to study the growth of galaxies and intracluster light in a dense environment in great detail. Using the spectroscopic observations from the Visible Multi-Object Spectrograph at Very Large Telescope (VLT/VIMOS) and mock HI observations of Fornax from TNG50 simulations allow us to learn about mass-assembly and intra-cluster environment. In this talk, I will present the kinematics of the GCs of the Fornax cluster core region and will discuss the distribution of baryonic and dark matter around NGC1399. I will discuss the kinematic substructure of the intra-cluster GCs, which indicates their accreted nature. In addition, I will also show that Fornax-like halos in TNG50 simulations hold a large amount of cold gas in their IC environment.