Seminars and Colloquia at ESO Garching and on the campus

The ALeRCE (Automatic Learning for the Rapid Classification of Events) broker processes real-time astronomical alert streams from surveys like ZTF and the upcoming Rubin Observatory. To handle this scale and complexity, we’ve developed a progression of machine learning models: from Random Forests using hand-crafted features to deep learning approaches such as CNNs on image cutouts, multimodal transformers combining light curves with tabular metadata, and, most recently, vision transformers for modeling complex variability in a multi-survey scenario. While these models are trained on labeled datasets, deploying them in production involves additional challenges. In this talk, I will outline our algorithmic evolution, the gap between training and inference in real-world alert streams, and how we balance real-time performance and generalization in a system designed for scientific discovery at scale. Finally, I will highlight high-impact discoveries, such as changing-look AGNs, candidate pair-instability supernovae, and new cataclysmic variables, which often come from close collaborators leveraging simple services or identifying multimodal inconsistencies. This highlights a key lesson for Rubin: community adoption often begins with simple use cases and gradually enables complex, high-impact science across diverse astrophysical phenomena.

Composite structures with tailored co-efficient of thermal expansion (CTE) for precision instrumentation

New Frontier Technologies (NFT) Pty Ltd is an Australian small-to-medium enterprise (SME) specialising in design,

additive manufacture, 3D analysis and digital twinning of high-performance carbon-fiber composite structures for high

precision instrumentation applications in telescopes and satellites. The NFT capability has been utilised to design and

manufacture composite structures with low or zero-CTE to ensure dimensional stability over a wide temperature range

to eliminate the risk of misalignment or de-focussing of optics and sensors during an observation. This is not possible

with the metals such as aluminium that are typically used for instrumentation structures.

This presentation will show results from a series of projects on the manufacture of composite structures for precision

instrumentation applications. They include:

• the main load-bearing barrel structure for the Dynamic REd All-sky Monitoring Survey (DREAMS) telescope, a

near-infrared fully automated all-sky survey telescope project

• a dimensionally stable optical mount for satellite instrumentation for bushfire monitoring (OzFuel satellite)

• a tapered, lightweight, near-zero-CTE composite lens barrel for the Canberra-based quantum optical ground

station (QOGS)

With the simple mind of a mathematician, I almost ran away from the lab when I started coding my SED fitter and encountered the "beautiful mess" of: magnitudes, photometric systems and filters (exact same name for two filters with remarkably different transmission curves), photon vs energy counting, etc. And even when finally the fluxes were in physical units... here comes the debate on what is the suitable lambda to use (for plotting!! :-)) and the strong opinions regarding fluxes and
density fluxes... Little did I understand at that point that it is not that astrophysicist like to complicate their lives (don't we?), but that there is a fascinating combination of historical and technical reasons that prevent having a "clean" and homogeneous way to go from what is observable to SI traceable flux measurements. In this ID I will go
briefly on how we calibrate now, why it is not enough for some cases and interesting initiatives in this context like the Landolt Satellite Project.

Debris disks represent the final evolutionary phase of protoplanetary disks. These systems, which form as byproducts 

of the planet formation process, may host planetesimal belts, dust, and gas. The dust observed in debris disks is expected 

to be removed by stellar radiation on timescales shorter than the system's age, indicating that dust must be continuously 

replenished through ongoing collisions between larger objects such as planetesimals. As in our solar system, the presence of 

dust, planetesimals, and planets in debris disks should be intrinsically linked. Moreover, since our solar system itself

experienced at least a close encounter in the last 3 Myrs, a possible event responsible for the formation and/or evolution of

debris disk systems are flybys. In this talk, I will present observational evidence for sub-structures, low-mass companions 

and close encounters in debris disk systems. I will also discuss their influence on the formation and evolution of these systems.

Abtract 1:

MICADO and MORFEO at the ELT will enable the study of galaxies on ≤100 pc scales across the entire Universe. This

unprecedented spatial resolution will revolutionize our understanding of galaxy morphology and internal physics across cosmic time.

Current spatially resolved studies, at kpc and sub-kpc scales, in the local Universe suggest that star formation is regulated by physical

processes that could be universal across various scales. Extending such investigations to higher redshifts, especially around cosmic

noon (z ~ 1–3), is essential to assess the role of internal morphological substructures in galaxy evolution and to identify potential quenching

mechanisms.
Thanks to the exceptional sensitivity and spatial resolution of JWST, spatially resolved analyses of galaxies at these redshifts are now feasible.

In this talk, I will present preliminary results from ScopeSim simulations of galaxies at cosmic noon, as observed with MICADO and MORFEO.

I will also compare them with JWST observations, focusing on the capability of detecting morphological features such as bars, spiral arms, and

stellar clusters, and discuss the implications for galaxy evolution studies with the ELT.

Multiwavelength information is crucial for a complete understanding of the Universe. In the era of big data, large-number statistics is the ideal tool to characterize the demography of galaxy populations and understand the complex phenomena involved in galaxy evolution. We present one of the largest uniform optical spectroscopic surveys of X-ray selected sources to date observed as a pilot study for the Black Hole Mapper survey (BHM). The BHM program of the Sloan Digital Sky Survey (SDSS)-V is designed to provide optical spectra for hundreds of thousands of X-ray selected sources from the SRG/eROSITA all-sky survey, significantly improving our ability to classify and characterize the physical properties of large statistical populations of X-ray emitting objects. Our sample consists of optical spectra of 13,079 sources in the eROSITA eFEDS performance verification field, among which 12,011 provide reliable redshifts from 0< z ≤ 5.8. We showcase the diversity of the optical spectra of the X-ray-selected AGN, and provide high signal-to-noise ratio spectral stacks in various sub-samples of different redshift and optical broad-band colours. Our AGN sample contains optical spectra of (broad-line) quasars, narrow-line galaxies, and optically passive galaxies, showing considerable diversity in colours and levels of nuclear obscuration.

In addition to reviewing the history of uncertainty relations, starting with Heisenberg's work in 1927, the talk will

discuss how all the standard inequalities – for products or sums of variances – follow from one basic equation.

The shortcomings of the "minimum-uncertainty states" for generic pairs of observables are exposed and advice

is offered on how to do better.

The shaping of planetary nebulae on their evolution from asymptotic giant branch (AGB) circumstellar envelopes (CSE)

to their final, most often axisymmetrical, form is still a process with many unknown details. For this, the study of the transition

objects, pre-planetary nebulae (pPNe), is key to understand the whole shaping process. After creating a detailed 3-D

morpho-kinematical model of M1–92, a pPN with one of the richest chemistry, we obtain a full description of the nebula’s

physical and chemical properties, finding robust discrepancies in the 12C/13C isotopic ratio across structures depending on

their age and linking it to its ongoing shaping process.

Star formation within galaxies is regulated by the circumgalactic medium (CGM) through gas inflows and outflows. I will present an analysis towards the multiphase (warm+cold molecular and ionized) gas and dust content toward a cool-core brightest cluster galaxy (BCG) at z=0.4, using JWST MIRI/MRS observations complemented by ALMA, MUSE, VLA, and Chandra data. The target harbours one of the largest known H2 reservoirs, elevated star formation, and an AGN. We obtained new JWST MIRI MRS observations that detect warm rotationally-excited H2 lines, PAH complexes, [Ar II], [Ne III] and [S IV] lines. The H2 line ratios indicate a different temperature distribution in the CGM compared to the interstellar medium within the BCG. The PAH complexes are found in dense clumps embedded within the more diffuse CGM along the radio emission, suggesting shock-driven star formation. I will discuss the implications of this pilot study on our understanding of higher redshift analogues, as well as the role of AGN feedback in regulating star formation. This case study serves as a pathfinder for using JWST to unveil the warm molecular gas in the circumgalatic medium for investigating the energy and mass flows in feedback processes.

Galaxies do not evolve in isolation. Most evidence suggests that galaxies’ evolutionary paths are influenced by their merger histories. Interactions between galaxies, and the gas they provide via accretion, can determine whether star formation in a galaxy will proceed rapidly or slowly. The local system of galaxies made up of the Milky Way and the nearby Magellanic Clouds provides a unique laboratory to study the processes governing the mergers of gaseous galaxies and whether magnetic fields trace and influence the gaseous merger. The Magellanic system is one of the largest coherent extragalactic features in the sky. In this talk, I will show new data from the ASKAP survey of atomic hydrogen (HI) in the Magellanic System and the ASKAP survey of magnetism, POSSUM. I will spend some time discussing the surveys in general and then show how together these surveys are hinting at the linked role of magnetism and atomic gas flow.

Interstellar dust has a significant impact on many astronomical research fields, 

as it absorbs and scatters a large fraction of the star light, and influences star formation 

and galaxy evolution at all cosmic times. Understanding the amount of dust, the 

properties of the grains, and the interplay between dust and radiation, is thus 

crucial to derive precise knowledge of any object in the Universe that is obscured 

by dust, as well as to constrain the initial conditions for star and planet formation. 

My research focuses on understanding how dust grains of different sizes and compositions 

affect multi-wavelength observations. I am particularly interested in what dust particles are 

made of, how they evolve, and how they interact with radiation at different wavelengths.

In this seminar, I will explain which methods I use to study dust in the Milky Way, and what we 

have learned so far. I will also show how combining the results of these approaches, and the 

synergy between multi-wavelength data from the James Webb and the Hubble Space 

Telescopes, as well as other observations, is advancing our understanding of interstellar dust 

properties and how they vary in different environments.

Gamma rays offer a unique window into the most energetic phenomena in our Galaxy, 

where compact objects and explosive events drive powerful outflows. 

In this talk, I will explore how gamma-ray observations — particularly those from 

Imaging Atmospheric Cherenkov Telescopes (IACTs) like H.E.S.S. — have revealed 

the role of galactic compact sources in injecting energy and particles into their 

surroundings. I will focus on pulsars, microquasars, and novae as three example 

of high-energy outflows, discussing how their gamma-ray signatures inform us 

about particle acceleration, shock formation, and magnetospheric processes. 

I will also discuss the future of the field and which new pieces of the stellar evolution 

can we expect to find with the new generation of Cherenkov telescopes. . 

Understanding the diverse formation and migration pathways that shape exoplanetary systems requires characterizing both their atmospheric properties and their orbital dynamics. A key dynamical diagnostic is the projected spin-orbit angle, the alignment between the stellar spin and the planetary orbit which provides crucial tests for theoretical models. This angle can be determined using the Rossiter-McLaughlin effect. Although measurements exist for over 200 planets, the overall distribution of these angles remains incompletely understood, motivating further observations across the full parameter space. In this talk, we present measurements of spin-orbit angles for 25 systems identifying several system that have likely underwent disc-free migration. We highlight the synergy between the two approaches and comment on the current overlap between targets with spin-orbit angle measurements and those having measurements for atmospheric characterization. While we find no strong observational biases due to the spin-orbit angle, we note that the majority of planets, with atmospheric data still lack spin-orbit measurements. This incompleteness of the dynamical information may limit the interpretation of upcoming atmospheric surveys.

Since the first imaging observation of the Beta Pic disk in 1984, the astronomical community has thoroughly investigated this system, finding large amounts of dust and gas, exocomets, and two planets. All of this makes it the perfect laboratory to investigate the dynamics and chemistry of the late stages of planet formation. Recent JWST observations using imaging and spectroscopy have revealed that the dynamical activity of the system is much more complex than initially expected, with a high collision rate that affects the composition and the morphology of the disk. 

I will present here an overview of the system focusing on the results from JWST program GTO 1411, that was designed to investigate the dust component at near- and mid-infrared wavelengths, providing new insights on the dust morphology, composition, and distribution. The combination of the high sensitivity of the on board instruments with the 4QPM and Lyot coronagraphs allows for the most detailed images of the Beta Pictoris disk so far at this wavelength range, revealing new features and details in the dust distribution. In this talk, I will present JWST NIRCam and MIRI coronagraphic images, ranging from 1.82 to 23 microns. I will also summarize the analysis of prominent disk features observed for the first time, and compare it to previous ground and space based observations at multiple wavelengths. 

The JWST/NIRSpec GTO program Galaxy Assembly with NIRSpec IFS (GA-NIFS) is leveraging ~330 hours of observing time to study a diverse sample of high-redshift galaxies, including clumpy star-forming systems, overdensities, AGN and luminous quasars. I will show the GA-NIFS contribution to the enhancement of data processing methods, resulting in improved data quality from the NIRSpec IFU. As a scientific case study, I will present the discovery of a ring galaxy at z ~ 3, revealed by NIRSpec IFS. The galaxy exhibits a bright nebular ring, a stellar bar-like structure, disturbed kinematics, and a nearby companion; these features can be consistent with either a collisional origin, a resonance ring from bar dynamics, or a post-compaction structure. I will share preliminary results on the system’s kinematics and ISM properties, illustrating both the scientific potential of NIRSpec IFS and the crucial role of custom data reduction in maximising JWST’s impact.

Planet formation remains one of the key unsolved challenges in modern astrophysics. Recent exoplanet discoveries and high-resolution observations of protoplanetary disks are reshaping our understanding, prompting a re-evaluation of classical planet formation theories. The omnipresent disk sub-structures helped us to solve the most significant challenges and are driving a new generation of planet formation models. At the same time, increasingly precise laboratory measurements of the Solar System materials provide invaluable benchmarks for the models, giving insights into timescales of planet formation and the large-scale mixing processes. In this talk, I will discuss the understanding of the Solar System formation, which is currently emerging from the synergy of numerical models and meteorite studies.

New deep surveys are uncovering increasingly extreme sources, challenging our understanding of what constitutes a galaxy. In the Lambda Cold Dark Matter (LCDM) model, galaxies form when the gas in dark matter haloes cools sufficiently to collapse and undergo star formation. However, some haloes may fail to collapse efficiently, leaving gas to accumulate without significant star formation. Such objects are known as ‘dark galaxies’, and although they would be completely invisible to optical telescopes, if they possess enough neutral atomic hydrogen gas (HI) then they should able to be detected with radio telescopes.  We examine the optical counterparts of the 1829 H I detections in three pilot fields in the Widefield ASKAP L-band Legacy All-sky Blind surveY (WALLABY) using data from the DESI Legacy Imaging Surveys DR10. We find that 17% (315) of the detections are optically low surface brightness galaxies (mean g-band surface brightness within 1 Re of > 23 mag arcsec−2) and 3% (55) are optically ‘dark’. We find that the gas-rich WALLABY LSBGs have low star formation efficiencies, and have stellar masses spanning five orders of magnitude, which highlights the diversity of properties across our sample. We assess the H I detections without optical counterparts and identify 38 which pass further reliability tests. Of these, we find that 13 show signatures of tidal interactions. The remaining 25 detections have no obvious tidal origin, so are dark galaxy candidates. Deeper H I and optical follow-up observations are required to verify the true nature of these dark sources.

X-ray surveys have been an effective way to study growing supermassive black holes (SMBHs). Utilizing X-ray survey fields that have extensive multiwavelength data coverage, we can probe how SMBH growth links with the properties of their host galaxies, which will ultimately help to investigate the physical mechanisms behind the potential coevolution of SMBHs and their hosts. In my talk, I will present the relation between SMBH growth and host-galaxy compactness (represented by the central surface-mass density) that we found among star-forming galaxies, which is more significant than the relation between SMBH growth and stellar mass or star formation rate. I will also present how the growth of SMBHs varies with Dn4000 (which is closely related to the age of stellar populations). We found that AGN fraction and SMBH growth level are higher among younger galaxies at Dn4000 < 1.9. Among the oldest/most massive galaxies at low redshift, this trend is not present,  which may be associated with additional fueling from hot halo gas and/or enhanced accretion capability.

The number of applications to graduate programs is growing extremely fast without a significant increase in the number of available positions, making it harder to run an admissions process that is fair and efficient. Last week, the AAS Graduate Admissions Task Force (GATF) released a summary of their final report, which includes recommendations aimed at improving the current state of graduate admissions in astronomy. One of the topics they addressed is the use of recommendation letters, which were also the focus of a recent open letter from early-career researchers to the GATF. In this ID, I’ll summarise the key points from both documents, focusing on the role of recommendation letters, with the aim to discuss together whether, in their current form, they are truly effective tools for evaluating students fairly and equitably.

Understanding complex organic materials on a molecular level in Bio- and/or Geosystems is a huge challenge in modern sciences and implies constant development and adaptation of modern ultrahigh-resolving analytical technology. We aim to present concepts for the chemical diversity of chemical mixtures and complex materials subjected to biotic and abiotic processes:
Life and Living systems (Biomes) from ubiquitous microbiomes through higher organisms to entire ecosystems. Chemical complexity is ruled by the genomes.
After-life involving generally globally transformed organic matter generating new complex materials not found in any database on short term or geological time scales to geopolymers in diagenetic processes.
Pre-Life complex chemistry involves prebiotic chemistry following the only rules of abiotic chemical reactions. These complex chemistry is found in meteoritic samples and from asteroid return samples (HAYABUSA2, OSIRIS ReX ). From this highest diverse and complex materials emerged molecules crucial for the early steps of life.

The classical evolutionary scenario for compact binary orbits involves common-envelope evolution. In the realm of massive stars, the result could be a Wolf-Rayet binary (such as Cyg X-3) or a helium-star system with orbital period under 10 hours and separation as close as 2 Solar radii. Recently, it was proposed that similarly close orbits could also be produced by stable mass transfer evolution, particularly if some of the non-accreted matter is ejected from the system with high angular momentum, leading to outcomes such as binary black hole mergers. In my talk, I will show that there is limit to how close the binary orbit may become without triggering mass transfer instability. Contrary to expectations, the separation limit does not depend on uncertainties in gas dynamics of interacting binaries and it holds even if extreme orbital shrinkage due to strong L2 outflows is assumed. Instead, the origin of the limit lies in the stellar structure, which dictates when the binary system gets unstable. Interestingly, different stars have their own different 'comfort zones', and this variety can be explained by their internal composition profiles. Consequently, compact binary systems can be a sensitive probe of chemical mixing in stellar interiors

Over the past decade, the landscape of academic publishing has changed dramatically, with publishers moving from subscription-based models to "open access" in which papers are available to read free of charge. Many journals have made the decision to maintain revenue by charging authors for this, via so-called "Article Processing Charges" (APCs) which can run to $1000s thereby closing the door on those without funds to pay. More recently, there have been moves to encourage researchers to publish using "Diamond" Open Access wherein papers are published without charge to the authors and without cost to the reader. In this talk I shall discuss the ennvironment for Open Access Publishing in Astrophysics with reference to the Open Journal of Astrophysics (OJAp), which offers a not-for-profit service of this kind using an arXiv-overlay model. I will also offer a possible vision of the future of truly "Open Access" publishing based on a global network of institutional and/or subject-based repositories.

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

At the center of nearly every large galaxy — including our own Milky Way — lies a supermassive black hole, weighing millions to billions of times the mass of our Sun. In some galaxies, these black holes actively feed on surrounding gas and dust, creating dazzling displays of energy known as active galactic nuclei(AGNs) — often outshining the light of all the stars in their galaxy. In this talk, we will explore what supermassive black holes are, how astronomers detect them, and what happens when they go into feeding mode. We will also dive into one of the most intriguing discoveries in modern astrophysics: black holes and galaxies do not grow in isolation, they appear to evolve together, shaping each other’s histories. Thanks to the James Webb Space Telescope, we are now peering farther back in time than ever before, uncovering surprising evidence of very massive black holes in the early universe. Using down-to-earth explanations, we will unpack the cosmic connections between galaxies and the powerful black holes at their cores.

The chemical enrichment state and dust attenuation of galaxies, their redshift evolution, and their dependence on stellar mass, star formation rate, and environment are some of the most readily testable predictions of theoretical models of galaxy formation. The complex interplay between the processes that regulate chemical enrichment, including mergers, accretion, star formation, and feedback-driven outflows is expected to become simpler at early times and easier to model. Hence, high-z constraints on the gas-phase metallicity and dust attenuation of galaxies are crucial for informing the theoretical models. I will present these measurements based on a large compilation of JWST/NIRSpec data, containing more than 2,000 galaxies at 3 < z < 14. I will highlight established correlations, including the mass-metallicity relation and its redshift evolution, as well as the fundamental metallicity relation. Moreover, I will highlight new findings concerning the cosmic buildup of interstellar dust. The revolutionary combination of depth, wavelength coverage, and spatial resolution afforded by JWST has brought morphological and chemical analysis to the forefront of high-z studies. However, we are already facing the limitations of space telescopes: (i) their limited spatial resolution, and (ii) the high exposure times required to acquire deep high-spectral resolution spectra. I will discuss these shortcomings in light of the upcoming class of ELTs, and highlight the improvements expected in the coming decade.

The lifespan of circumstellar disks dictates the timescale for planet formation. Comparing different star- and planet forming regions introduces uncertainties due  to varying distances, sample completeness, and environments. However, new tailored clustering  algorithms applied to Gaia data enable us to study these evolutionary processes within a single,  coherent region. In this talk, I will present results from such a study on the Scorpius-Centaurus  OB Association. I will show our surprising findings on circumstellar disk lifetimes, detail a  statistical model for disk lifetime estimation, and discuss the implications and limitations of  these results.

On Monday, 11 November 1974, two experimental teams reported independent evidence for
a remarkably stable meson, about three times the proton’s mass. A group led by Sam Ting at
the Massachusetts Institute of Technology studied proton-Beryllium interactions at
Brookhaven National Laboratory’s 30-GeV Alternating Gradient Synchrotron. Their new
particle, which they named J, was observed to decay into electron–positron pairs at a
combined mass of 3.1 GeV. A collaboration of scientists from the Lawrence Radiation
Laboratory in Berkeley and the Stanford Linear Accelerator Center found the same particle,
which they named ψ, in electron–positron annihilations at the SPEAR storage ring.
Subsequent events confirmed that the new particle was composed of a new “charm” quark
and its antiparticle, the first of a new family of mesons that we call charmonium. The
existence of what came to be known as the J/ψ particle had been foreseen, but not with such
singular properties. In a sense, we got what some of us wanted, but what arrived was far
more dramatic than we had dared to hope. The twin discovery catalyzed a phase transition in
our understanding of the natural world. In this colloquium, I will present a portrait of the world
into which J/ψ was born, unleashing the “November Revolution” of 1974 and the birth of the
standard model of particle physics.

Tidal disruption events (TDEs) are among the most fascinating astronomical phenomena, offering a unique probe into the properties of massive black holes and the nuclear environments of galaxies. In this talk, I will present results from theoretical calculations of the realistic rates of TDEs for both supermassive and intermediate-mass black holes. These results reveal how TDE rates depend on black hole mass, stellar dynamics, and galactic environments. I will also show state-of-the-art simulations of TDE accretion, outflows and emissions, demonstrating how these processes produce the diverse emission features we observe, including Bowen fluorescence lines. Finally, I will discuss the broader implications of TDEs for black hole growth, particularly in the early universe, and their role in shaping galactic evolution. By exploring these results, we can better understand the physics of TDEs and their critical role in the growth of black holes and the evolution of galaxies across cosmic time.

Star formation regions in the solar neighborhood are the only places where we can resolve processes like gas cloud formation and dispersal, or stellar evolution, in great detail. The youngest stars found in active stellar nurseries are arguably the best tracers of their parent cloud motion. However, shrouded by gas and dust, they are missing from astrometric surveys like Gaia. To measure their motions and investigate the coupling to their natal cloud we instead have to turn to, e.g.,  infrared wavelengths. 
In this talk, I will first give an overview of the ESO public survey VISIONS, which aims to provide proper motions for embedded young stellar objects (YSOs), complimentary to Gaia. Then I will demonstrate the successful derivation of infrared YSO proper motions and investigation of the kinematics of stars and gas in a pilot study of the NGC 2024 cluster, located at d~400 pc in the Orion B molecular cloud. Lastly, I will offer an outlook on the broader context of star formation in the solar neighbourhood, using recent findings from the star formation group in Vienna.

It is almost 100 years since the expansion of the universe was observationally discovered. Since then, astronomers argued on what the exact expansion rate is and how the universe will develop. Major refinements of the measurement of the Hubble constant have been introduced in the past decades. The latest developments led to an inconsistency of some of the measurements. The Hubble tension is the topic of active discussions, and the controversy is challenging the current cosmological model.

Brown dwarfs have been extensively studied in nearby star-forming regions (d < 400 pc). However, theories suggest that high gas or stellar densities, as well as the presence of massive OB stars, may enhance brown dwarf formation relative to stars. To test this, it is crucial to study brown dwarf populations in massive young clusters, which provide dramatically different star-forming conditions. The nearest examples of such clusters are the supermassive star clusters (SSCs) Westerlund 1 and Westerlund 2, each exceeding 30000 Msun in total stellar mass.
As part of the EWOCS (Extended Westerlund 1 and 2 Open Clusters Survey) project, we have obtained deep JWST/NIRCam observations of these clusters. A key goal of this project is to derive their mass functions and assess whether extreme environments influence brown dwarf formation. By combining these results with studies of other massive young clusters led by members of the project, such as Trumpler 14 and RCW 38, we are placing the first robust constraints on the efficiency of brown dwarf formation in such environments.
In this talk, I will present the JWST/NIRCam data products of both clusters, the (sub)stellar initial mass function of Westerlund 1, and the detection and characterization of brown dwarfs in Westerlund 2, enabled by the rich multi-wavelength filter selection. I will also discuss the implications of these results for our understanding of star formation.

Ultra-Diffuse Galaxies  (UDGs) are a class of low surface brightness galaxies defined based on their extremely low central surface brightness μ0>24 g mag  arcsec−2) and large size in terms of the effective radius (Re>1.5 kpc). In this study, we compare the structural parameters of UDGs to those of other dwarf galaxies and investigate whether UDGs form a distinct population. We observed deep u'-, g'-, and r'-band images (maximum limiting surface brightness [3σ, 10'' × 10''] u' and g': ≈ 30 mag arcsec−2; r': ≈ 29 mag arcsec−2) of Abell 1656 (Coma cluster) and Abell 262 with the 2.1 m-Fraunhofer Wendelstein Telescope at the Wendelstein Observatory. We measure u' ‑ g' and g' ‑ r' colors and structural parameters using parametric fitting of tens of thousands of potential UDGs and other dwarf galaxies. Cluster members are automatically identified and separated from diffuse background galaxies based on red sequence membership and their location on the quiescent sequence in the u' ‑ g' vs. g' ‑ r' color-color diagram. Further interloping galaxies are removed using a Mtot−μe selection cutoff above which the sample is expected to be dominated by background galaxies based on the comparison with a reference field.

Black hole scaling relations of local quiescent galaxies and star formation rate histories suggest supermassive black holes may regulate galaxy growth. Understanding the central regions of AGN is crucial to understanding the role that supermassive black holes may play in galaxy evolution. Dynamical modeling of velocity-resolved reverberation mapping data sets allows one to infer the structure and kinematics of the broad line region (BLR). To date, nearly 30 AGN have been modeled with this approach and studies indicate diverse BLR kinematics among these objects. This diversity further validates the need for an observational proxy for the virial coefficient used in traditional reverberation mapping analyses and single epoch black hole mass measurements. Future work, including a larger sample of objects with dynamic modeling, has significant potential to improve the way black hole masses are calibrated across cosmic time.

The Epoch of Reionization (EoR) marks a critical phase in the evolution of the universe, yet remains poorly understood. While star-forming galaxies are acknowledged as key contributors to ionized bubble formation, the extent of contribution from alternative sources such as shock-heated ISM or emission from X-ray binaries remains unclear. In this study, we employ cosmological radiative transfer simulations to explore the impact of diverse sources on intergalactic medium (IGM) properties. Our focus is not merely data fitting, but rather understanding whether the interpretation of Lyman-ɑ forest observations is changed by using theoretical models incorporating non-stellar sources.

Moving beyond the EoR, the study explores the Epoch of Helium Reionization (HeEoR), when HeII transitions to HeIII (𝑧 ≲ 4), predominantly driven by quasar-produced ionizing photons. Using the parametrization of the quasar luminosity function (QLF) proposed by Shen et al. (2020), we examine its implications for recent observations suggesting an extended HeEoR.

Finally, the study delves into the origin of UV luminosity function (UVLF) variability, potentially explaining the unexpectedly high abundance of UV-bright galaxies at extreme redshifts observed by JWST. By exploring the stochasticity of star formation and dust attenuation driven by different implementations of supernova feedback, we provide insights into the UVLF's evolution and its link to early galaxy morphologies. This presentation will highlight these findings and their broader implications for our understanding of cosmic reionization.

Active Galactic Nuclei (AGN) are among the most luminous and energetic objects in the Universe. Studying them is key to understanding the co-evolution of galaxies and their central supermassive black holes (SMBHs). At the same time, their brightness and ubiquity across cosmic time make AGN promising tools for cosmology. In this talk, I will explore the dual perspective of using AGN as cosmological probes while simultaneously refining our understanding of their physical properties. This two-way approach helps us progress on both fronts—learning more about the Universe while gaining deeper insight into AGN, their physics, and their evolution.  I will begin with the non-linear relation between the X-ray and UV luminosities of quasars. This correlation can be used to construct a Hubble diagram extending to redshift ~4, providing a way to test cosmological models. I will present recent results and discuss the tension this method reveals when compared with predictions from ΛCDM. I will then turn to AGN variability—particularly in the X-ray band—as a potential distance indicator. Data from current and upcoming observatories and surveys such as Euclid, NewAthena, and LSST, variability-based methods may provide a complementary approach to building the AGN Hubble diagram. Finally, I will focus on the potential of the BLR based geometric distances to derive the H0 constant by combining reverberation mapping and spectroastrometric measurements from GRAVITY. 

Protoplanetary discs can be deeply affected by the UV radiation from massive stars (mainly OBA). External photoevaporation, which leads to a reduction in disc mass, size, and lifetime, is relevant even in moderately irradiated environments (1-100 G0). I used an innovative approach to statistically compute the FUV flux and its uncertainty: using the 2D geometry of a star-forming region and its local density distribution, I provided the best estimate of the 3D separation between discs and massive stars (which is the highest source on uncertainty in flux calculation). I compiled a catalogue of the FUV flux at the position of a large sample of discs in 14 nearby star-forming regions, covering distances from Taurus, to Orion and Serpens.  Upper Scorpius, part of the regions explored by the AGE-PRO Large Program, provides a unique laboratory to study the effects of external photoevaporation at 1-100 G0. I compared AGE-PRO observed disc masses and radii with the outcomes of dustpy simulations, with and without external photoevaporation. The results from the viscous external photoevaporation model closely align with the observations for seven out of ten sources, while the pure viscous framework fails to explain AGE-PRO observations.  This study provides better estimates of the FUV field experienced by discs in the nearby star-forming regions, emphasizing the crucial role of external photoevaporation in moderately irradiated environments. Average disc properties in different star-forming regions should not be compared on the sole basis of age, but also accounting for the role of the environment.

More than 7500 extrasolar planets are known, most of them are located within our solar neighborhood where they orbit stars different than our Sun. How does the climate differ on extrasolar planets that orbit such different host stars? By building and utilized virtual laboratories temperature, wind and cloud maps of such extrasolar planets can be predicted and studied. Our virtual laboratories are therefore vital tool to interpret observations from, e.g. space missions like CHEOPS and JWST, and to make predictions for future missions like PLATO and NewAthena. For this, our present focus is on giant gas planets since they have observable atmospheres, and hence, enable us to link modeling and observation to understand their physics and chemistry.

Clouds most often block the view into the atmospheres and hence, hinder the spectroscopic in-depth characterization of the many known exoplanets. Of particular interest is therefore the understanding and the modeling of cloud formation which forms a tight feedback-loop with the local temperature but also the local gas phase composition. The local gas phase is further affected by the external high-energy radiation, including stellar energetic particles and cosmic rays. I will demonstrate why gas giant exoplanets are exciting objects that allow to study cold, cloud forming and hot, ionizing thermodynamic regimes in one and the same objects.

The circum-galactic medium (CGM) can feasibly be mapped by multiwavelength surveys covering broad swaths of the sky. With multiple large datasets becoming available in the near future, we develop a likelihood free Deep Learning technique using convolutional neural networks (CNNs) to infer broad-scale physical properties of a galaxy’s CGM and its halo mass for the first time. Using CAMELS (Cosmology and Astrophysics with MachinE Learning Simulations) data, including IllustrisTNG, SIMBA, and Astrid models, we train CNNs on Soft X-ray and 21-cm (HI) radio 2D maps to trace hot and cool gas, respectively, around galaxies, groups, and clusters. Our CNNs offer the unique ability to train and test on “multifield” datasets comprised of both HI and X-ray maps, providing complementary information about physical CGM properties and improved inferences. Applying eRASS:4 survey limits shows that X-ray is not powerful enough to infer individual halos with masses log(Mhalo/Msun) < 12.5. The multifield improves the inference for all halo masses. Generally, the CNN trained and tested on Astrid (SIMBA) can most (least) accurately infer CGM properties. Cross-simulation analysis – training on one galaxy formation model and testing on another – highlights the challenges of developing CNNs trained on a single model to marginalize over astrophysical uncertainties and perform robust inferences on real data. The next crucial step in improving the resulting inferences on the physical properties of CGM depends on our ability to interpret these deep-learning models.

The MHONGOOSE Large Survey Project is obtaining ultra-deep 21-cm neutral hydrogen (HI) observations with the MeerKAT radio telescope to map the distribution and kinematics of the low column-density gas in and around 30 nearby star-forming spiral and dwarf galaxies. These deepest resolved HI observations of nearby galaxies to date serve to put additional constraints on the role of accretion of cold gas in the replenishing of these galaxies' gas reservoirs. Observations for the survey have just completed and MHONGOOSE is routinely reaching its target HI column density sensitivity of a few times 10^17 atoms cm^-2, two orders of magnitude lower than the typical values found in galaxy HI disks. Our full-depth data show that the outskirts of our galaxies are complex and dynamic environments, with many potential accretion and interaction features visible in HI that only now become visible due to the excellent column density sensitivity.  We detect a significant number of uncatalogued low-mass dwarf galaxies, which enable "Local Group science" in environments at tens of Mpc distance. A first comparison of the MHONGOOSE observations with simulated HI maps from recent cosmological simulations show a marked difference in kinematics and morphology, indicating that cold gas accretion is likely happening in a more gentle way. The sensitive MHONGOOSE observations point the way to a better understanding of the role of gas accretion in galaxy evolution in the nearby universe and identifies opportunities for new HI surveys with the upcoming SKA-MID telescope.

Type Ia and other peculiar supernovae (SNe) are thought to originate from the thermonuclear explosions of white dwarfs (WDs). Some of the proposed channels involve the ejection of a partly exploded WD (e.g. Iax SN remnant) or the companion of an exploding WD at extremely high velocities (>400 km s^-1). Characterization of such hyper-runaway/hypervelocity (HVS) WDs might therefore shed light on the physics and origins of SNe. Here we analyse the Gaia DR3 data to search for HVS WDs candidates and peculiar sub-main-sequence (sub-MS) objects. We retrieve the previously identified HVSs and find 46 new HVS candidates. Among these we identify two new unbound WDs and two new unbound sub-MS candidates. The remaining stars are hyper-runaway WDs and hyper-runaway sub-MS stars. The numbers and properties of the HVS WD and sub-MS candidates suggest that extreme velocity ejections (>1000 km s^-1) can accompany at most a small fraction of type Ia SNe, disfavouring a significant contribution of the D6-scenario to the origin of Ia SNe. The rate of HVS ejections following the hybrid WD reverse-detonation channel could be consistent with the identified HVSs. The numbers of lower-velocity HVS WDs could be consistent with type Iax SNe origin and/or contribution from dynamical encounters. We also searched for HVS WDs related to known SN remnants but identified only one such candidate ( https://ui.adsabs.harvard.edu/abs/2023MNRAS.518.6223I/abstract).

Our understanding of planet and star formation is mainly based on already formed planets around (sub-)solar-like stars. In this talk, I aim to broaden our perspective by focusing on protoplanetary disks around more massive stars, leveraging the special properties of their stellar interiors. In particular, convective sub-photospheric regions disappear during the pre-main-sequence evolution of stars with masses roughly between 1.5 and 4 Msun. In turn, the absence of convection influences the mixing of stellar material, the strength of the magnetic field, and consequently, the way disk material is accreted by the central stars. I will summarize our recent findings on the metallicity and accretion properties of intermediate-mass young stars in relation to disk structures, the potential presence of giant planets, and the size of their innermost orbits. I will conclude by presenting our ongoing efforts to reliably determine disk-to-star accretion rates of the most massive young stars with fully radiative envelopes.

Numerous protoplanetary disks exhibit shadows in scattered light observations. These shadows are typically cast by misaligned inner disks and are associated with observable structures in the outer disk such as bright arcs and spirals. Investigating the dynamics of the shadowed outer disk is therefore essential in understanding the formation and evolution of these structures. We carry out two-dimensional radiation hydrodynamics simulations that include radiative diffusion and dust–gas dynamics to study the formation of substructure in shadowed disks. We find that spiral arms are launched at shadow edges, permeating the entire disk. The local dissipation of these spirals results in an angular momentum flux, opening multiple gaps and leading to a series of concentric, regularly-spaced rings. We find that ring formation is favored in weakly turbulent disks where dust growth is taking place. These conditions are met for typical class-II disks, in which bright rings should form well within a fraction of their lifetime (~0.1–0.2 Myr). For hotter disks gap opening is more efficient, such that the gap edges quickly collapse into vortices that can appear as bright arcs in continuum emission before decaying into rings or merging into massive, long-lived structures. Synthetic observations show that these structures should be observable in scattered light and millimeter continuum emission, providing a new way to probe the presence of substructure in protoplanetary disks. Our results suggest that the formation of rings and gaps is a common process in shadowed disks, and can explain the rich radial substructure observed in several protoplanetary disks.

Neutrinos are fascinating particles heralding the dawn of multi-messenger astronomy. Neutrinos affect the stellar dynamics, drive the formation of new elements, and carry signatures of the yet mysterious physics governing the most energetic transients in our universe. Recent developments on the role of neutrinos in cosmic sources will be reviewed together with the most exciting multi-messenger detection prospects.

Dusty star forming galaxies (DSFGs) are increasingly understood to be the primary contributors to the cosmic star formation rate density at least out to z~4 and sites of proto-cluster environments. We modeled the far-infrared and millimeter spectral energy distributions (SEDs) of 71 DSFGs selected at millimeter wavelengths by the Atacama Cosmology Telescope (ACT) with a lower flux density limit than previous catalogs of galaxies selected at the same wavelength. All candidates were cross-identified with detections in the Herschel SPIRE maps, and decomposed into possible multiple counterparts using a probabilistic cataloging (PCAT) algorithm. We obtained targeted observations of nineteen of our sources using the Submillimeter Array (SMA) telescope to acquire high resolution imaging and flux extraction to compare to the lower-resolution, single dish fluxes as well as assess the validity of the case for multiple components. In this talk, I will discuss the physical properties of the galaxies if they are treated as single sources with flux densities indicated by the single dish observations, but in this we exercise caution. ACT's lower flux limit, the PCAT decomposition, and the higher-resolution SMA observations all suggest that many of these DSFGs are likely to be unlensed and possibly multiples. I will then highlight the need for more efficient mapping of DSFG environments out to high redshift, and what the future may hold for unveiling the growth of structure through the (sub-)mm lens.

Galactic cosmic rays and stellar energetic particles are relativistic particles that reach exoplanets. Depending on their energy, they can penetrate exoplanetary atmospheres, similar to what occurs on Earth. The main properties, relevant for these energetic particles, that vary for exoplanetary systems in comparison to the solar system are the stellar winds properties, the exoplanet atmosphere composition and the stellar energetic particle spectrum. The properties of stellar energetic particles for stars other than the Sun remain elusive.

For exoplanetary atmospheres, one of the most important effects due to Galactic cosmic rays and stellar energetic particles is that they ionise the atmosphere. This ionisation leads to exotic chemistry depending on the atmospheric composition. Energetic particles can also drive the formation of prebiotic molecules, the building blocks of life in exoplanet atmospheres. These effects are also relevant for the early Earth atmosphere.

I will discuss our simulation results which show the ionising impact of energetic particles in exoplanetary atmospheres and the early Earth atmosphere. I will show how the stellar wind can affect the energetic particle flux reaching an exoplanet. Finally, I will discuss how JWST could detect the signature of energetic particle-induced chemistry in an exoplanet atmosphere. Such a detection could be used to constrain the energetic particle flux impacting on the exoplanet atmosphere.

I will review the magnetospheric accretion model as applied to T Tauri stars and the properties of protoplanetary disks that can be inferred from its application, including gas temperature, surface density, inner edge of dust disk,  molecular dissociation/ionization, and disk Ionization structure. I will discuss recent findings on the highly inhomogeneous nature of the magnetosphere. I will finish discussing the application of the magnetospheric models to find the abundances of refractory materials reaching the innermost disk, and what they can reveal about the history of the disk.

Selecting AGN candidates from photometric data, with the goal of spectroscopic follow-up, is a challenging yet essential task for spectroscopic surveys. In this study, we use a Random Forest classifier on photometric data from the Zwicky Transient Facility (ZTF) to identify AGN candidates. To target low-stellar-mass galaxies, we crossmatch these candidates with the NASA-Sloan Atlas (NSA) catalog, focusing on galaxies with stellar masses 𝑀∗<2×1010𝑀⊙. Using archival optical spectra from SDSS, we confirm the AGN nature of 357 (86%) out of 415 candidates through the presence of broad emission lines. Additionally, using data from eROSITA data release 1, we find that 67% of the candidates in the eROSITA-DE sky have an X-ray counterpart.

The discovery of over 5,000 exoplanets has revolutionized our ability to address fundamental questions about planetary habitability and evolution: Are there Earth-like worlds in the Universe? Can they support life? My research accelerates the discovery and characterization of habitable planets by combining cutting-edge observations with advanced models to characterize the atmospheres and surfaces of rocky and low-temperature exoplanets, trace their evolutionary pathways, and search for signs of liquid-water oceans.

In this talk, I will discuss recent breakthroughs in the study of rocky exoplanets, including the first detection of a magma-ocean atmosphere on 55 Cancri e and the discovery of a volcanic, SO₂-rich atmosphere on L 98-59 b using JWST. These findings provide unprecedented insights into the interplay between geological processes and atmospheric evolution, establishing the emerging field of exoplanet geology. I will also present ongoing efforts to identify liquid-water conditions on temperate sub-Neptunes, illustrating how innovative models, such as our next-generation planetary atmosphere framework, EPACRIS, enable us to predict key atmospheric signatures and interpret groundbreaking JWST observations. 

Finally, I will discuss the path forward for characterizing Earth-like planets and highlight how today’s exoplanet studies drive scientific and technological priorities of future exploration.

I will describe an extended, ongoing observational effort aimed at discovering and studying the properties of a large sample of dual and strongly lensed QSOs at sub-arcsec separations. With these data, we will be able to address numerous scientific questions, including testing several previously untested predictions of galaxy/SMBH evolution models, developing more accurate predictions of massive BH merger rates and LISA GW event rates, and studying dark matter distribution in the central kpc of lensing galaxies. We select candidates using Gaia and Euclid data and follow up on targets with various space- and ground-based telescopes, including an ESO large program with VLT/MUSE, to obtain spatially resolved spectroscopy. This has produced, for the first time, a substantial sample of confirmed dual AGN beyond the local universe, and the most compact quadruply lensed QSO ever discovered.

The origin of supermassive black holes (SMBH) in galaxy centers remains uncertain. They could have emerged either from massive "seeds" (100k-1M MSun) in the early Universe or from smaller (100 MSun) remnants of massive Pop-III stars, which would leave behind numerous intermediate-mass black holes (IMBHs, 100-100k MSun). The largest published sample of bona-fide IMBH-powered AGN contains only 14 objects confirmed in X-ray. I will present X-ray confirmation of 24 new optically selected IMBH candidates from a sample of 305 objects taken from Chilingarian+2018. Additionally, using the same method, we investigated 100+ AGN powered by "light-weight" SMBHs (<1e6 Msun). For the selection and confirmation of this sample, we used a multiwavelength approach utilizing both archives and our follow-up observations: optical spectra from SDSS for initial sample selection, different epoch spectra from observations with VLT, Keck, Magellan, and SALT, high-resolution imaging from HST and Magellan, and, ultimately, X-ray confirmation of sources with eROSITA, Chandra, XMM-Newton, and SWIFT. In this talk, I will present the statistical properties of our sample of X-ray confirmed IMBHs and its implications for BH growth scenarios.

Adaptive optics (AO), originally used for correcting the effect of turbulence on images in ground-based telescopes, has now been used for more than 25 years to image targets at cellular- and subcellular-scale for applications in the biological sciences. Using AO to correct the static and dynamic optical aberrations of the living human eye, has provided revolutionary tools to scientists and clinicians to study the retinal structure and function, revealing details without the need for histology. AO ocular imaging is non-invasive and easily tolerated by patients . Applied to high-resolution imaging of the living human eye with Scanning Laser Ophthalmoscopes (SLO) and Optical Coherence Tomography (OCT), this talk will cover the most relevant aspects to consider when designing a closed-loop AO imaging system for ocular imaging.

The last decade of observations of protoplanetary discs have shown a wealth of substructure including rings, gaps and spiral arms. Perhaps most intriguingly these observations also revealed the importance of the 3D structure of discs, where some discs are observed to have orientations that change as a function of radius or may also be broken. These so called 'warped discs' have challenged our understanding of disc evolution, and recent work has shown that these discs form a significant fraction of the disc population. In this talk I will discuss the connection between warped discs and the onset of planet formation, a major open question in planetary science.

Observational surveys of the distribution of matter in the universe are becoming ever more precise and continue to be extended to smaller scales. This necessitates accounting for the fact that baryons do not precisely trace the dark matter. The redistribution of baryons by galactic winds, which is the major bottleneck in our understanding of  galaxy evolution, therefore requires a convergence between models of large-scale structure and cosmology. I will present results from the FLAMINGO suite of large-volume cosmological, hydrodynamical simulations. The fiducial simulations have been calibrated using machine learning to reproduce the low-z galaxy mass function and cluster gas fractions, but the suite also includes systematic variations in the galaxy formation model and cosmology. The simulations provide insight into the importance of baryonic effects for cosmology using large-scale structure and galaxy clusters.

The Gaia mission has recently completed its last scientific observations. This is a good time to reflect on why this is a great mission, with one of the worst data access policy. I will provide a biased view on some of the revolutionary results it led to and provide a brief overview of what is still planned for the young and patient people in the audience.

Gamma-ray emission produced by interactions of cosmic rays with interstellar matter and radiation fields is a probe of non-thermal particles in galaxies. After decades of technological advancements in gamma-ray astronomy, several key results have significantly advanced our understanding of cosmic ray physics. However, there are still a few critical questions that remain unresolved. This review offers an overview of the current state of the field, while also exploring how next-generation gamma-ray facilities can further advance research in this area. Specifically, we will highlight the capabilities of the Cherenkov Telescope Array Observatory (CTAO). CTAO will be the first proposal-driven observatory in this energy range, providing science-ready data to the global research community.

Quantum Computing (QC) is a paradigm with disruptive potential in many areas of computational sciences and large projected impact in research, industry and society. In my talk I will provide a general overview of the main concepts of QC and how it can be integrated into the High-Performance Computing ecosystem as a suitable tool for astronomy and astrophysics. Although application areas in these disciplines are in the first stages of exploration, a few promising directions will be highlighted. Finally, the access paths to QC systems for the local research community will be described.

Galaxies don’t just form stars—they continuously exchange gas with their surroundings. This circumgalactic medium (CGM) is a turbulent, magnetized mix of gas shaping how galaxies evolve. Observations reveal a multiphase CGM, but capturing this complexity in simulations is a major challenge due to small lengthscales involved. 

In this talk, I will explore:

- Why small-small effects in multiphase astrophysical gas are important?

- How turbulence & magnetic field shape CGM structure?

- How a new subgrid model can bring these small-scale effects to large-scale cosmological simulations?

By improving how we model the CGM, we can better interpret observational data and refine our understanding of galaxy evolution. Let's talk about how we can make that happen.

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The Informal Discussion is in-person only, and held in the ESO library.

At around 10:30, we will continue in the discussion at science coffee.

The Herschel observations unveiled the complex organisation of the interstellar medium in networks of parsec-scale filaments over the past decade. Despite their variety of scales throughout the interstellar medium, the analysis of these same observations revealed filaments in nearby low-mass clouds to have a characteristic width of ~0.1 pc. The origin of this characteristic width and its impact on star formation, however, has been a matter of intense discussions in the past years. Even more with the identification of small-scale filamentary structures harboured inside the Herschel filaments. These networks of fibers have been recognised describing the gas structures in star-forming regions at sub-parsec scales, thus critically challenging the existence of a typical width for filaments.I am going to present our study of the dense gas organisation prior to the formation of stars in a sample of 7 star-forming regions within Orion. This EMERGE Early ALMA Survey includes OMC-1/-2/-3/-4 South, LDN 1641N, NGC 2023, and the Flame Nebula, all surveyed at high spatial resolution (4.5'' or ~2000 au) in N2H+ (1−0) using ALMA+IRAM-30m observations. I will present the star-forming gas spatial distribution, its column density variations, its thermal structure, and its internal motions across the 152 fibers identified in our survey.

Over the past 15 years, the Atacama Large Millimeter/submillimeter Array (ALMA) in the Chilean desert has revolutionized our understanding of planetary formation. ALMA has not only provided the expected large samples and high-resolution images of planet-forming material, but it has also led to groundbreaking discoveries that challenge existing theories. One of the most striking revelations is that planets form much faster than previously thought. In this talk, I will explore the key concepts and scales involved in the process of building planets from micrometer sized cosmic dust. I will discuss how theory and observations help us reimagine how planetary systems, both similar and very different from our own, are formed.

In order to understand galaxy growth evolution, it is critical to constrain the evolution of its building block: gas. Mostly comprised by Hydrogen in its neutral (HI) and molecular (H2) phases, the latter is the one mostly directly associated to star-formation, while the neutral phase is considered the long-term gas reservoir. Both phases are difficult to detect directly either due to high excitation temperatures or low transition probability. As a result, while HI direct observations have been limited to the local Universe and extended to high redshifts when seen in absorption, H2 has been traced indirectly via tracers, either Carbon Monoxide (CO) rotational transitions, atomic Carbon fine structure transitions, or dust emission at (sub-)mm wavelengths. However, the latter best tracers the combined content of HI and H2 masses. In this work (Messias et al. 2024), we make use of an empirical relation between dust emission at millimeter wavelengths and total gas mass in the inter-stellar medium (M_HI plus M_H2) in order to retrieve the HI content in galaxies. We assemble an heterogeneous sample of 335 galaxies at 0.01<z<6.4 detected in both mm-continuum and carbon monoxide (CO) low-J transitions. More specifically, a blindly selected sub-sample had a special focus given its suitability to retrieve HI cosmological content when the Universe was ~2-6 Gyr old (1<z<3). Overall, we find no significant evolution with redshift of the M_HI/M_H2 ratio, which is about 1–3 (depending on the relation used to estimate M_HI). This also shows that M_H2-based gas depletion times are underestimated overall by a factor of 2–4. Compared to local Universe HI mass functions, we find that at least the number density of galaxies with M_HI>1E10.5 Msun significantly decreased since 8–12 Gyr ago. The specific sample used for this analysis is associated to 20-50% of the total cosmic HI content as estimated via Damped Lyman-alpha Absorbers. In IR luminous galaxies, HI mass content decreases between z~2.5 and z~1.5, while H2 seems to be constant or increase. Finally, the results obtained in this work allow us to report source detection predictions for SKA1 surveys and what is the most suitable strategy to detect HI at cosmic noon.

Recent simulations of AGN feedback have found that the impact on the host galaxy’s gas changes during an AGN phase. Using radio-AGN that harbour bright jets, we can trace young and evolved AGN phases, and even multiple AGN phases in a single source. New and ongoing large area surveys like LoTSS (with LOFAR) and VLASS (with VLA), now make it possible to build large samples of radio-AGN and characterise their spectra. Combining this with optical spectroscopic surveys like SDSS and MaNGA can provide interesting insights into the link between the radio-AGN life-cycle and feedback. In this context, I will present our results on radio-AGN feedback on ionised gas, where we find evidence for [OIII] kinematics to be most disturbed during the young AGN phase (on average), which lasts for ~0.1-1 Myr after the AGN is triggered. We find that the feedback on [OIII] is intrinsically linked to the evolutionary stage of an AGN phase, irrespective of source luminosities, black hole and stellar masses, and accretion rates. I will then discuss the relative contribution of jets and radiation in low luminosity radio-AGN, combining LoTSS and MaNGA. Finally, I will briefly present our ongoing work on jet-ISM interaction in a high-redshift (z~3.5) radio-AGN.

Since 2017, the Atacama Large (sub-)Millimeter Array (ALMA) has been participating in regular Very Long Baseline Interferometry (VLBI) observations both with the Event Horizon Telescope (EHT, at 0.8–1mm) and the Global Millimeter VLBI Array (GMVA, at 3–7mm). The advent of ALMA in this type of observations has resulted in a revolution in our capability to image and study the environment around super-massive black holes (SMBHs) down to event horizon scales, and thus the way we infer their properties. In this presentation, I will justify why we need these observations of SMBHs, and go through the results obtained towards M87* and SgrA* thus far, but also other sources that, unfortunately, did not receive equal attention (eg, CenA, 3C279, OJ287, NRAO530). I will then finalize with the near-future capabilities of VLBI observations with ALMA, but also the capability of ALMA-standalone phased-array observations for time-domain studies with timing precisions down to ~100microsec.

The boundaries of relativistic black hole jets—at the interface between the jet and the disk wind—lie at the core of our recent understanding of jet-powered phenomena. They harbor intense velocity and magnetic shears, which provide the free energy needed to power a number of observational signatures. We demonstrate that magnetic reconnection—a process by which opposite field lines annihilate, releasing their energy to the plasma—ultimately governs dissipation of the available free energy at jet boundaries. Reconnection resulting from the nonlinear evolution of Kelvin-Helmholtz type vortices can naturally explain the limb-brightened radio emission of AGN jets, such as M87. Also, inverse Compton scattering within the chain of magnetic islands / flux ropes self-consistently created by reconnection at the jet boundaries can power the mysterious hard X-ray “coronal” emission of X-ray binaries. We will also argue that reconnection-driven hadronic acceleration in the coronal regions of NGC 1068 may be the source of the TeV neutrinos recently detected by IceCube.

Quasar microlensing is both an invaluable astrophysical tool and a complicating factor in measurements like the Hubble constant from lensed quasars. Previous studies have focused on the Einstein ring crossing time for a single microlens, but the combined gravitational effects of the lens galaxy (mean field) and other microlenses (fluctuating field) significantly influence microlensing properties. In this talk, I will present our recent work extending a statistical analysis of microlensing to all currently known lensed quasars with available data, incorporating realistic optical depths, updated quasar sizes, and galaxy peculiar velocities. By generating microlensing magnification maps using the fast multipole method and inverse polygon mapping, we find a mean source crossing time, and an Einstein radius crossing time.  Moreover, I will highlight how interactions among microlenses and the overall gravitational shear play crucial roles, with approximately 13% of quasar images experiencing high-magnification events. These results have important implications for quasar microlensing and future observational campaigns.

Fellowship selection processes in academia are designed to reward scientific excellence, yet research suggests that bias—especially unconscious bias—can subtly influence evaluation outcomes, often disadvantaging underrepresented groups. In this informal discussion, we will first explore the impact of bias on selection processes, with a particular focus on hidden, unconscious biases that shape decision-making without evaluators even realizing it We will then examine how prestigious fellowship programs, including Marie Skłodowska-Curie Actions (MSCA), the European Research Council (ERC), and other major astronomy and astrophysics fellowships, attempt to mitigate these biases. Using insights from peer-reviewed studies and official funding reports, we will analyze how different selection panels confront issues such as Halo bias, linguistic bias, and cognitive bias.

An exciting new window into the circumgalactic medium (CGM) has opened up with the recent observations of the thermal and kinetic Sunyaev-Zel’dovich (SZ) effects on galactic spatial scales. I will present the ongoing efforts to extract these galaxy scales SZ signals in data from the Atacama Cosmology Telescope. I will show how these observations are currently being used to constrain important physical processes, like feedback, that govern galaxy formation. Additionally, I will present some puzzles these observations pose to state-of-the-art cosmological simulations. I will conclude by highlighting the expected rapid growth in such SZ
observations over the next decade with the upcoming millimeter and sub-millimeter focused experiments, like the Simons Observatory, CCAT, and CMB-S4.

Observing campaigns have revealed a great diversity in exoplanetary systems whose origin is yet to be understood. How and when planets form, and how they evolve and interact with their birth environment, the protoplanetary disks, are major open questions. Protoplanetary disks evolve while planets are forming, implying a direct feedback between the processes of planet formation and disk evolution. These mechanisms leave clear imprints on the disk structure that can be directly observed. In this talk, I will review recent observational results on protoplanetary disks, in particular those from the exoALMA Large Program, the first sub-millimeter planet hunting campaign. With exquisite molecular line observations, the velocity structure of fifteen protoplanetary disks revealed a variety of kinematic perturbations possibly due to embedded protoplanets, (magneto-)hydrodynamical instabilities or winds.

An efficient coupling between the energy released by Active Galactic Nuclei (AGN) and the interstellar medium (ISM) of their host galaxy can generate kpc scales outflows which may regulate the rate at which stars can form and ultimately influence the growth of the galaxy.  These AGN driven outflows include gas in various phases (ionized, atomic, molecular) but at z>1, due to the limitations of current instrumentation, we are usually forced to adopt a single-phase (ionized) view of the outflow phenomenon which may lead to wrong estimates of their extent, mass and energetics, therefore ultimately misinterpreting their relevance for galaxy evolution. JWST/MIRI can be used to overcome some of the previous limitations, and to map the mid-infrared ro-vibrational H2 lines to complete the multi-phase characterization of the ISM. We report some recent MIRI/MRS observations that allow us to detect hot-molecular gas in the host a bright quasar at z~2 with already well characterized kinematics of the ionized gas showing a galactic scale AGN-driven outflows. We will compare this newly detected gas component with the other phases of the ISM and with predictions from simulations. 

Almost all accreting black hole and neutron star X-ray binary systems (XRBs) exhibit prominent brightness variations on a few characteristic time-scales and their harmonics. These quasi-periodic oscillations (QPOs) are thought to be associated with the precession of a warped accretion disc, but the physical mechanism that generates the precessing warp remains uncertain. Relativistic frame dragging (Lense-Thirring precession) is one promising candidate, but a misaligned magnetic field is an alternative, especially for neutron star XRBs. Here, I will present the discovery of 5 accreting white dwarf systems (AWDs) that display strong optical QPOs with characteristic frequencies and harmonic structures that suggest they are the counterpart of the QPOs seen in XRBs. Since AWDs are firmly in the classical (non-relativistic) regime, Lense-Thirring precession cannot account for these QPOs. By contrast, a weak magnetic field associated with the white dwarf can drive disc warping and precession in these systems, similar to what has been proposed for neutron star XRBs. The presented observations confirm that magnetically-driven warping is a viable mechanism for generating QPOs in disc-accreting astrophysical systems, certainly in AWDs. Additionally, they establish a new way to estimate magnetic field strengths, even in relatively weak-field systems where other methods are not available. And furthermore, I will discuss the possible new application of the model to explain mHz QPOs in Ultraluminous X-ray Sources (ULXs).

Stellar evolution and planet formation could meet when it comes to post-asymptotic giant branch (post-AGB) binary systems. In such systems, the evolved pair of stars are surrounded by stable, massive circumbinary discs. These discs show surprisingly many similarities with protoplanetary discs around pre-main sequence stars, including dust mass, Keplerian rotation, infrared excesses, and the disc physics near the dust sublimation rim. These similarities raise the question whether a second episode of planet formation processes are taking place in these discs around evolved stars. Studying these discs can bring significant implications on our understanding of circumstellar disc physics and this in a peculiar parameter space (short disc lifetime, high stellar luminosity, different disc formation mechanism and environment). I will show results of observing campaigns mainly with the VLTI to probe the inner regions of these discs, how these can help to uncover the disc physics, and how we can link the circumstellar discs across the stellar evolutionary stages.

For more than 50 years mankind has invested in human space exploration. Since then, astronauts have orbited the Earth and landed on the moon, installed the Hubble Space Telescope, and expanded the scope of exploration in unprecedented ways. In addition to all the experiments and technological advances these missions have given us a completely new perspective on our home planet seen as a ‘pale blue marble’ in space. This is the essence of the Overview Effect.

The chemical evolution of high-redshift galaxies is key to understanding galaxy formation. Using data from the MARTA Survey and deep JWST/NIRSpec observations, we detected multiple, faint auroral lines in star-forming galaxies at z∼2–3, enabling precise electron temperature-based metallicities during 'Cosmic Noon,' the peak epoch of star formation. Our results provide a recalibration of strong-line diagnostics and refine the sulfur and oxygen temperature relations

The importance of mental health and the need for finding the right balance between work and life is something that is rarely, if ever, talked about, especially in academia. Yet, many students and faculty alike feel the stresses of modern life and suffer from the pressure to constantly perform, achieve and produce. According to the American College Health Association, students reported stress, anxiety, sleep trouble and depression as the top four impediments to academic achievement, and 9 of the 10 top factors are mental health and/or coping skills related. The importance of maintaining mental health has never been more obvious and urgent. The benefits of mindfulness to body, mind, and emotional well-being are well established by medical research and include greater peace of mind, happiness and the ability to relax from the stresses of current times. In this workshop, Dr. Vardha N. Bennert will present an introduction to mindfulness and meditation. She will guide participants in short mindfulness practices that can be used as tools in everyday life. She will also facilitate group discussions.

Bio: To balance her work as a teacher and researcher in physics and astronomy, Dr. Bennert has been practicing various forms of meditation and body-awareness practices (such as Tai Chi, QiGong, Yoga and conscious dance) for the past 20+ years of her life and has also participated in numerous personal growth workshops. Throughout her career, she has been approached by students struggling with finding a healthy work-life balance, resulting in uplifting conversations that inspired her to offer workshops like this one.

Format: pedagogical lecture plus in-depth discussion

I will summarize 3 recent papers about galaxies at z>=10, and the Ho tension. I will then discuss, without offering solutions, whether such results place the standard Cosmological model en course towards the rocky shores of a funtamental(s) crisis.

There is now a distinct possibility that neutral atoms and even molecules can exist in the extreme environments near the Supermassive Black Holes (SMBHs) that power the Active Galactic Nuclei (AGN), even in the absence of dust and the presence of strong UV/X-ray radiation fields. The corresponding spectral lines may yield  new spectral windows to AGNs as well as new tests of General Relativity in strongly curved Spacetimes.

Studies of protostellar accretion and outflow processes have been revolutionized by the incredible power of JWST. Investigating Protostellar Accretion (IPA) is a Cycle 1 JWST program that targeted 5 young, inclined protostars in their primary accretion phase, spanning the mass spectrum, with the NIRSpec and MIRI MRS IFUs. The data enables exploration of the signatures of accretion and outflow through spectral mapping of the inner regions of protostars with high spatial and spectral resolution. The rich datasets clearly show the nested morphology of protostellar outflows just hundreds of au from the driving source. These data consistently show collimated jets traced by shock-ionized [Fe II], surrounded by narrow shells of warm H2, within wide-angle outflow cavities traced by the scattered-light continuum. H2 is observed filling the shells, showing probable evidence of molecular winds or expanding bow shocks. Shocked knots in the jets are detected in molecular, neutral atomic, and ionic tracers. Preliminary results from a morphological and kinematic analysis of the collimated jets from three of the protostars show evidence of wiggles and bends in the jets, as well as asymmetries between jet and counterjet. Using the jet velocities found from the higher spectral resolution MIRI MRS, the mass and momentum outflow rates are estimated. These data provide the clearest picture yet of protostellar outflows during the deeply-embedded primary accretion phase.