Seminars and Colloquia at ESO Santiago

Recent advances in astronomical instrumentation and observational techniques have allowed us to detect the "invisible" - galaxies that are tens of times fainter than the dark night sky.  These low-surface brightness systems span a vast range in baryonic mass, from 1e7 to 5e11 Solar masses.  In this talk, I will present our recent observational findings on the high-mass end of low-surface brightness galaxies.

The largest low-surface brightness disk galaxies prototyped by Malin-1 are typically found in sparse environments.  These giant systems, with disks extending beyond 100 kpc, still continue to grow.  Our recent observational campaign has examined their structure, stellar populations, gas and stellar kinematics, and gas-phase metallicity profiles.  This work has revealed several distinct subclasses of giant low-surface brightness galaxies (gLSBGs), suggesting diverse formation pathways.  While many of these systems appear to result from intermediate to major mergers, there is compelling evidence for ongoing, slow gas accretion in some cases.  Surprisingly, we often find compact elliptical satellites -- remnants of larger progenitor galaxies -- orbiting these massive disks. From a uniform analysis of a large patch of the sky, we estimated the volume density of gLSBGs and found that they are not that exceptionally rare as it had been thought in the past: in the whole sky we expect about 13,000 systems out to z=0.1.

Giant LSBGs provide unique insights into star formation and galaxy evolution in low-density, dark matter-dominated regime at the highest end of the galaxy mass function.  The current Euclid mission, along with upcoming surveys from the LSST at the Rubin Observatory and future spectroscopic campaigns, promises to revolutionize our understanding of the low-surface brightness Universe, likely revealing new aspects of galaxy evolution in this still poorly explored but crucial area of study.

Core-collapse supernova (CCSN) rates across the redshifts holds important information on how galaxies and their star formation have evolved over cosmic time. This study aims at shedding light on the connection between CCSNe and star formation rates (SFR) by using new high-redshift CCSN rates from the JWST Advanced Deep Extragalactic Survey (JADES). For this, the observed CCSN rates are compared with the expected rates based on the cosmic star formation history using both chi-square and Markov Chain Monte Carlo (MCMC) analysis. Effects of dust obscuration, metallicity (fallback into a blackhole), binary stellar populations and the initial mass function (IMF) are investigated. We find that correcting the observed CCSN rates for dust obscuration and taking fallback into account becomes especially important at redshifts higher than z ~ 0.5. Our findings show no significant variation in the results when using the Salpeter, Kroupa, or Chabrier IMFs.

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I will present master’s thesis where I performed photometric and spectroscopic analysis on two type IIb supernovae, 2017gkk and 2019gaf. The observations were obtained using the Nordic Optical Telescope (NOT) and they cover epochs from early days to about a year after the explosion. The motivation for this long time series of spectra and light curves was to better understand the physics of core-collapse supernovae and especially transitional type IIb SNe. In the future I will publish result from my thesis and do more through analyses.

We will share what we have learned with the "Breaking the Barriers" project, which was supported by  ESO-Chile Joint Committee funds. We will discuss different strategies and ideas to keep in mind when engaging with people whose primary language is sign language.

The origin of brown dwarfs is still a matter of debate, being the "star-like formation" or the "planet formation within a protostellar
disk and subsequent ejection" the most accepted formation mechanisms. In order to shed light on their origin, different groups
have tried to detect and characterize these objects at the earliest stages of their formation, when they are still embedded in their
parental clouds.  In this talk, I will present a database collecting all these observations, the SUbstellar CANdidates at the Earliest
Stages (SUCANES) database, and I will show different applications of SUCANES to shed light on the formation of brown dwarfs.

Ultra-diffuse galaxies (UDGs) present profound challenges to our understanding of dark matter theories and galaxy evolution. Despite their significance, observational limitations have impeded progress in elucidating their evolutionary pathways and roles. LEWIS (Looking into the faintEst WIth muSe) represents a pioneering effort, approved under ESO-P108, to address this gap by conducting a comprehensive spectroscopic survey of UDGs within the Hydra I cluster using MUSE@ESO-VLT. This ESO TMT talk focuses on (1) The LEWIS project: main sample properties and resolved stellar kinematics and (2) Stellar populations analysis of 17 LEWIS UDGs. Building upon previous findings (Buttitta et al. submitted, Iodice et al. 2023), we have verified significant trends and bimodalities (in metallicity, alpha enhancement, and overall star formation histories) depending on the UDG phase-space positioning within the cluster. Exciting outliers that defy the assumption of a single unified formation scenario are discussed. Our analysis not only reinforces the knowledge of some of the existing general UDG properties (e.g. Ferré-Mateu et al. 2023, Buzzo et al. 2024) and proposed evolution pathways but also introduces novel insights and significantly enhanced statistical robustness, shedding new light on the enigmatic nature of UDGs and their place in the cosmic narrative of galaxy evolution.

Dual AGN—pairs of active galactic nuclei residing in the same galaxy—are a crucial population for understanding black hole (BH) mergers and their connection to the gravitational wave (GW) background. These systems serve as progenitors of merging BHs, making their properties essential for predicting GW event rates for pulsar timing arrays (PTAs) and the future LISA mission. Additionally, dual AGN provide key insights into galaxy formation and evolution by revealing BH mass functions, separation distributions, and redshift-dependent properties. Despite their importance, our knowledge of dual AGN is limited, with few systems detected at sub-arcsecond separations. 
On the other hand, Strong gravitational lensing is key to address many open challenges of current cosmological models, by modeling the inner mass density profile and the level of dark matter substructure within the lensing galaxy. High resolution observations of these systems are needed to put strong constraints on the lensing mass modeling at kpc-scale.
Using Gaia’s innovative “multi-peak” (GMP) technique, numerous multiple AGN have been identified at sub-arcsecond separation, and several ground-based AO-assisted instruments (Keck, VLT, and LBT) are needed to confirm their nature as dual AGN or gravitationallensed systems.
In this talk we will present the physical properties of dual AGN, encompassing parameters such as masses, luminosity functions, separation distribution, and their evolution with redshifts and the first statistical outcomes to validate model predictions on galaxy evolution and predict the event rate of GW signals.
Then, we will show ERIS/NIX high-resolution observations of the smallest quadruple lensed quasar detected so far (~0.3" separation) and spectroscopic follow-up, thanks to which we measured a spectroscopic lens z=1.055, one of the farthest lensing galaxy ever detected. We measured the stellar mass, the gravitational mass, the dark matter distribution across different radii and the level of substructures in a unprecedented combination of mass, scale and redshift.
Our study shows the potential of the novel GMP technique in selecting hundreds of small-scale dual and lensed AGN system, that coupled with high-resolution follow-ups can be used to address key astrophysical and cosmological questions.

I will present a comprehensive overview of my nine-year research journey in Chile, focusing on the processes involved in the formation of stars and brown dwarfs. Using high-resolution observations from the Atacama Large Millimeter/submillimeter Array (ALMA), my work examines various stages of brown dwarf formation in the Lupus star-forming region, tracking their evolution from prestellar cores to Class II sources across optical to submillimeter wavelengths. Additionally, I will discuss molecular outflows associated with molecular jets in very low-mass stars and their relation to the origins of brown dwarfs. Through the eDisk ALMA large program, I have also explored the possible presence of substructures in Class 0 low-mass stellar disks, which sheds light on early planet-forming systems. Notably, I will share the first indications of substructures within a brown dwarf disk—an exciting discovery that may reveal new insights into planet formation processes within substellar environments. This research enhances our understanding of how brown dwarfs and low-mass stars form and evolve, offering valuable insights into the mechanisms governing the lower end of the star formation regime.

Low-surface-brightness galaxies (LSBGs) are defined as galaxies with central surface brightness fainter than the night sky. These galaxies represent a unique and elusive population that is challenging to observe and characterise. A key unresolved question is whether their low brightness arises from intrinsic properties or from stochastic or unusual events in their formation history. In this work, we introduce a straightforward method to estimate the surface brightness of galaxies modelled in the EAGLE hydro-dynamical simulation. We classify them into two populations: low-surface-brightness (LSB) and high-surface-brightness (HSB) galaxies. To eliminate potential biases, we strictly matched the stellar and halo mass distributions of these two populations. This approach leaves us with a balanced sample of 3,000 central galaxies, enabling a detailed study of their redshift evolution and exploration of the parameter space across 100 galaxy and halo properties. We provide statistically robust measurements of the properties that show the most significant differences between LSBs and HSBs. On average, LSBs exhibit larger stellar half-mass radii, more extended discs, lower star formation rates, and higher angular momenta. Most notably, at fixed halo and stellar masses, LSBs exhibit the maximum stellar velocity at larger radii compared to their HSB counterparts. Our investigation of the redshift evolution reveals that LSBs and HSBs begin to diverge around z∼2−3. Furthermore, LSBs tend to reside in early-assembled, less-concentrated halos. We hypothesis that the primary drivers of low surface brightness features in galaxies are linked to their mass assembly history, dynamical properties such as angular momenta and distribution of stellar mass in the galaxy as well as the co-evolution of their dark matter halos. Importantly, we find no evidence that the large-scale environment plays a significant role in this process.

In this talk, I will summarize the discovery of giant low surface brightness galaxies (gLSBGs) and the efforts to uncover and understand their most remarkable characteristics. I will focus on their stellar and gas properties, with particular attention to their unique star formation processes.  I will discuss recent observations and potential scenarios that may explain  the formation of these extraordinary objects. I will highlight recent advances regarding one of the most iconic gLSBGs—Malin 1, the largest spiral galaxy observed to date. 

This is a mini-workshop focused on stellar abundances, offering hands-on sessions dedicated to determining stellar parameters and chemical abundances in FGK stars. This workshop presents an excellent opportunity for PhD students and early career postdocs to engage with international experts in the field, fostering valuable discussions and collaborations.

The workshop will be structured as follows:

• Each morning will feature scientific lectures covering a range of topics: nucleosynthesis and Galactic chemical evolution; stellar populations, dwarf galaxies, and stellar streams; chemical studies of planet-host stars; and large spectroscopic surveys along with the automated, data-driven analysis pipelines that facilitate them. This session will be open to in person and online participants.
• Afternoons will be dedicated to hands-on experiences at three levels of complexity.
  • 1st day, participants will perform a manual single star, line-by-line analysis.
  • 2nd day will introduce a state-of-the-art physics-based automated analysis code.
  • 3rd day will focus on machine learning-based codes.

These sessions are exclusively designed for 25 in-person junior researchers (final year of master, PhD candidates and postdocs up to 3 years after PhD), with a special focus on welcoming participants from the Chilean community.

The goal is to provide participants with a comprehensive overview of the techniques, possibilities, and challenges in the chemical abundance analysis of cool stars, and their scientific applications. Participants will gain the skills to effectively use these tools in their research endeavors.

Pulsating stars, such as hot subdwarfs and white dwarfs, provide key insights into the final evolutionary stages of low- and intermediate-mass stars through asteroseismology. These stars exhibit brightness variations with periods of 100 to 14,000 seconds and amplitudes up to 0.4 magnitudes. Continuous high-cadence time-series photometry, particularly from space missions such as Kepler, K2, and TESS, has significantly advanced our understanding by enabling precise frequency measurements and innovative asteroseismological techniques. This review explores the role of asteroseismology in studying these compact stars, highlighting recent developments in observational methods, theoretical models, and the contributions of both ground-based telescopes and space missions, while also considering future prospects in the field.

Low-mass galaxy groups, the most common environments for galaxies, are essential to our understanding of both cosmological processes and galaxy evolution. However, their hot gas content and baryon distribution remain poorly constrained due to their low X-ray surface brightness. Current X-ray selection methods might potentially miss groups with lower X-ray luminosity because of active galactic nuclei (AGN) feedback, thus not representing the average properties of the sample. I will show how using X-ray stacking of optically selected groups we can dig deeper into X-ray faint low-mass end of galaxy cluster population, confirming the methodology using state-of-the-art hydrodynamical simulations.  This approach not only probes the properties of intra-group medium gas in clusters on scales comparable to our own Local Group but also expands and validates existing X-ray scaling relations to the very low-mass end and traces the influence of AGN feedback on baryon distribution in groups.

Working with MUSE datacubes is as exciting as it could be daunting, due to their size and complexity. During this python coffee I will present MPDAF, a python tool specifically developed to work with MUSE data. Based on standard python packages (astropy, numpy, matplotlib), MPDAF significantly simplify the exploration and analysis of MUSE data. It provides dedicated tools for simple visualization of cubes, spectra and images, but also some advanced routines for spectral fitting, line identification, segmentation and mosaic creation. In this tutorial, we will focus on the basic of MPDAF data handling before moving to some of the more advanced tasks.

A full understanding of galaxy evolution requires a complete description of the role of cold gas as the primary fuel for star formation. The amount of cold gas in galaxies and the efficiency of gas conversion into stars determine many galaxy properties. Molecular gas observations, particularly through CO emission, are directly linked to star formation over cosmic time. While ALMA has made significant progress in this field, the limited scales of previous surveys and the potential effects of cosmic variance have limited the accuracy of cosmic gas mass density measurements. Here, I present the ALMA Calibrator Dataset (ALMACAL), a large untargeted survey of 1064 calibrator fields across the southern sky. Covering over 1000 square arcminutes and accumulating over 2000 hours of integration time, ALMACAL surpasses previous surveys in volume by at least ten times. I will present the methods for processing and imaging a subset of the highest-quality data. Our findings will include the CO luminosity function based on detections found from ALMA Band 3 to 9 and the cosmic evolution of molecular gas up to redshift z~6. I will discuss the significance of these results in revealing the critical role of cold gas in the baryon cycle of galaxies.

In order to make progress on the use of SNIa for cosmology (“Is the Universe departing from a LambdaCDM?”), stellar evolution and exoplanets (“What is the age of the star I am observing?”), absolute flux calibration to better than 0.5% or absolute color to better than 0.4% are necessary. The workshop brought together experts in HST, JSWT, Roman, Euclid, GAIA, and Rubin calibration, calibrators (mainly white dwarfs), NIST (“What does SI-traceability mean?”) and approved space missions (SPHEREx, NEO Surveyeor, UVEX), including a satellite dedicated to absolute flux calibration (Landolt), to discuss the challenges ahead to reach such accuracy.

Hydrogen-rich superluminous supernovae (SLSNe-II), characterised by their extreme peak brightness (<-20 mag), represent the most luminous end of Type II supernovae (SNe II). Their extreme brightness is thought to arise from a combination of massive progenitor, dense circumstellar medium (CSM), and the interaction between the supernvoa ejecta and CSM. However, the exact mechanism powering their light curve remains unclear. Additionally, their similarity to Type IIn supernovae (SNe IIn), which exhibit narrow interaction lines and are often slightly brighter than ordinary SNe II, has raised questions about the distinction between SLSNe-II and SNe IIn. In this study, we present an analysis of SN 2021aaev, a SLSN-II with well-sampled UV-optical photometry and flash spectroscopy. Spectroscopic follow-up reveals flash ionisation features that persist for over 2 weeks, marking the first time such features have been observed in a SLSN-II. Flash features are common among SNe IIn and serve as strong evidence of CSM interaction. Given the rarity of studies on SLSNe-II with flash features, our work provides key insights into the powering mechanism of SLSNe-II and their distinction (or lack thereof) from SNe IIn.

Most stars, including the Sun, are born in rich stellar clusters containing massive stars. Therefore, the study of the chemical reservoir of massive star-forming regions is crucial to understand the basic chemical ingredients available at the dawn of planetary systems. We present a detailed study of the molecular inventory of the hot molecular core G31.41+0.31 from the project GUAPOS (G31.41+0.31 Unbiased ALMA sPectral Observational Survey). We analyze 34 species for the first time plus 20 species analyzed in previous GUAPOS works, including oxygen, nitrogen, sulfur, phosphorus, and chlorine species. We compare the abundances derived in G31.41+0.31 with those observed in other chemically-rich sources that represent the initial and last stages of the formation of stars and planets: the hot corino in the Solar-like protostar IRAS 16293–2422 B, and the comets 67P/Churyumov-Gerasimenko and 46P/Wirtanen.

Active galactic nuclei (AGN) are today broadly recognized in galaxy evolution theories. One approach to understand the influence (and its extent) of AGN is by studying outflows and gas kinematic disturbances on their host galaxies using integral field spectroscopy (IFS). Still, disentangling the details remains challenging due to selection effects and the complexities of the AGN duty cycle. Therefore, we combine IFS data from SDSS-IV MaNGA (∼10.000 galaxies) and multiwavelength AGN selection techniques to study ionized gas kinematic disturbances. With this, we present two studies that shed light on the role of AGN in galaxy evolution: (1) we find that purely radio-selected AGN exhibit greater enhanced line widths across all radii compared to purely optically selected AGN. This suggests that our radio-selection technique is sensitive to finding more perturbed kinematics, and also to a population where AGN-driven kinematic perturbations have been active for longer (or repetitive) durations. (2) I will also show that kinematic disturbances in the ionized gas are higher when radio-GHz detections is present in galaxies. We start by focusing on star-forming galaxies with GHz detections and compare them to controlled non-GHz detected counterparts. I will show that further spectral analysis suggests that the GHz population may be experiencing light echoes from recently turned-off AGN events, indicating recent AGN activity and a more advanced evolutionary stage. We highlight the importance of multiwavelength observations and IFU data for understanding the connection between AGN and galaxy evolution.

The Low Resolution Halo Survey of the Milky Way (S1) is one of several  programmes to be undertaken with the upcoming 4-metre Multi-Object Spectroscopic Telescope (4MOST). 4MOST will observe ~2400 objects simultaneously, resulting in spectra from which will be derived parameters and chemical abundances for stellar targets. Reaching deep and faint, 4MOST will providing the necessary information for  S1 to study the formation and evolution of the Milky Way halo. I will present an overview of expected 4MOST stellar data products and the science goals of S1.

Anxiety is one of the most important mental health problems of this century. We will show some studies to stimulate discussion and we will present some tips or tools to cope with it and to help others.

Mapping the distribution of baryonic mass in our Universe down to the group-sized halo masses it is essential to clarify how much baryonic matter is locked up in halos and in filaments. Non-gravitational processes affect the thermodynamical conditions of the hot gas and baryonic content of groups and clusters of galaxies, causing deviations from the theoretical self-similar expectations. Indeed, many observational studies advocate a thermal feedback (such as the one provided by black holes residing in central galaxies) to explain their findings on the hot gas and overall baryonic content. Combined X-ray and optical data can allow us to investigate these features down to group scales, thanks to the unprecedented sensitivity reached by state-of-art telescopes in X-ray (i.e. eROSITA) and spectroscopic optical surveys such as SDSS, GAMA and WEAVES. In order to provide a fair comparison and be able to address the possible observational biases, we design a multiwavelength lightcone extracted from cosmological hydrodynamical simulations. We mimic the observational conditions and generate synthetic datasets that closely resemble the observations of galaxies in cluster/group-size halos. The lightcone incorporates the effects of various physical processes, including gas dynamics, feedback and several sources of contaminants. By combining the X-ray and optical properties of galaxies in the simulations, we can explore the hot gas on both large-scale structure and the galaxy population. In conclusion, I will present the results of this analysis which poses the foundations for future studies devoted at addressing all these observables.

There is dust in the close vicinity of main-sequence stars with temperatures of 1000K and more, but as of today this phenomenon is not fully understood. The dust should either sublimate or be repelled by radiation pressure on short time scales. However, due to the challenge of detecting dust that is just tens of milliarcseconds separated from a main-sequence star, the observational constraints are limited and based solely on interferometric data. We are working to improve the constraints with new observations using VLTI/MATISSE.
I will give an introduction into the topic of hot exozodiacal dust and then present the status of an ongoing analysis of the system kappa Tucanae.

The metal enrichment across the baryon cycle of galaxies is crucial for understanding galaxy evolution. Supernovae expel metal rich gas away from galaxies and inflows inject pristine gas. Simulations show that outflows are the main mechanism in redistributing metals and are key drivers of the chemical enrichment of galaxies and their circumgalactic medium. However, measuring metal abundance is challenging and therefore direct observations are almost completely lacking from the literature. I will present results from ESO/X-shooter, ESO/MUSE and Keck/KCWI where we measure outflow metallicities by detecting the very faint [O III] 4363 auroral line, a robust metallicity tracer, in both the disk and outflow of a sample of galaxies. These observations allow us to estimate the metal loading factor, a critical parameter for realistic simulations and compare with results from absorption line analysis and to recent simulations of metal-enrichment in winds.

The abundance of planets has led to population-level trends that may be imprints of planet formation and evolution. This can be revealed by recently developed modelling efforts that also provide planet composition predictions. For example, small planets might be classified as rocky, water, or gaseous based on their orbital or physical properties. Such properties are often observable via precise characterisation of the masses and radii of planets. In this colloquium, I will present ongoing observational work with the CHEOPS and TESS spacecrafts and HARPS-N instrument to study terrestrial planets to determine the internal compositional nature of these bodies and test demographic model predictions. I will also outline the upcoming PLATO mission, including its efforts to characterise long-period planets using spacecraft photometry and ground-based follow-up data. By studying exoplanets similar to Venus and the Earth, PLATO will advance our overall understanding of planet formation and evolution, and put our own planet in a Galactic context. 

This Python Coffee will be about learning how to query databases such as the Minor Planet Center (MPC) as well as accessing catalogs from Vizier by using the libraries of the same names, and being able to adjust parameters to fine-tune your search. You will learn to create a mosaic of FITS files by using the tools provided by the reproject library. Lastly, you will get to know the basics of creating a simple graphic user interface (GUI) with PyQt5.

Recent observations obtained at the ESO VLT have allowed us to set strong constraints on the origin and evolution of the magnetic fields of white dwarfs, and on the way the magnetic field may interact with the remnants of the planetary system orbiting around the star. After reviewing the work that has been done since the discovery of the first magnetic white dwarf, I will present the main results that we have obtained in the last three years, and that can be summarised as follows. (1) There are at least two different channels for the origin of the magnetic field, one for ultra-massive white dwarfs that are the product of the merging of two white dwarfs, and one for white dwarfs that are the product of single star evolution.  (2) Magnetic fields can drive the accretion of material from the debris of a planetary system, and be responsible for the formation and persistence of metal patches at the magnetic poles of metal-polluted white dwarfs. (3) Strong magnetic fields of old white dwarfs are symmetric about the stellar rotation axes; this symmetry may be either a consequence of field evolution, or a physical characteristics intrinsic to the way strong fields are generated in stars after the beginning of the core-crystallisation.

The ALMA Observing Tool (OT) is an application used for the preparation and submission of ALMA proposals and, for those which are accepted, for the generation of the Scheduling Block. In this talk I will present this tool from the perspective of the Subsystem Scientist, highlighting the OT’s strengths and complexity, as well as the parts where improvements are needed. Finally, I will also introduce the upcoming new generation OT (ngOT), which is currently under development, with a short demo.

ALMA has embarked on the wideband sensitivity upgrade (WSU), which aims to increase the spectral bandwidth the ALMA receivers by up to 4 times the current one, while at the same time improving the sensitivity and spectral resolution. This very ambitious goal requires a range of new technological development including new digitizers (bringing a sensitivity improvement of >10%), a new more versatile correlator, and new receivers. I will give an overview of the range of ongoing and planned developments, with an emphasis on the crucial role played by the ESO member state institutes in the WSU. The new digitizers are crucial to allow to cover any frequency within the IF range from 2 to 20 GHz, the benefit of which will already be seen with the current receivers. The Band 2 receiver which is currently being installed is the first one that will meet the WSU requirements, covering the IF range from 2 to 18 GHz. The next receivers which ESO plans to upgrade are Bands 7 and 9, where I will provide an overview of the current state and the remaining technical challenges to meet the WSU requirements in these receivers.

Molecular gas is closely related to star formation in galaxies and is an essential ingredient to understand how galaxies evolve. In the past 20 year, a large amount of new observations of the molecular gas have given new insight into this topic. In this lecture, I will review the basics of how molecular gas mass is measured and its uncertainties and I will present what we know about the global molecular gas content in galaxies, the resulting scaling relations and what they mean for our understanding of galaxies and their evolution.

The majority of massive stars end their lives in a violent explosion called a supernova (SN). In some cases, the stars may have lost their hydrogen and helium layers before the explosion, producing a type Ic SN. SN 2017dio is a type Ic SN that exploded in a hydrogen-rich circumstellar medium (CSM). The CSM is usually produced by the mass loss of the progenitor, but in the case of SN 2017dio, the hydrogen-rich CSM suggests that the CSM may originate from a companion star instead, indicating a very complex evolution and interaction process. SN 2017dio has proven to be a challenging case for stellar evolution theory on how to produce the progenitors of this kind of SN. We present late-time spectra and light curves of SN 2017dio, which are dominated by the ejecta interacting with CSM. Our goal is to determine the properties of the CSM by modelling the lightcurve and analysing the hydrogen emission line profiles. We identify an infrared excess in the light curves, which may have originated from infrared echo produced by pre-existing dust. By modelling this echo, we can derive the CSM properties at even greater distances. By deriving the CSM properties at different distances we can study the radial distribution of the CSM. This, in turn, tells us about the time evolution of the progenitor mass-loss history, which can shed light on the mass-loss mechanism and evolution of massive stars in binary systems.

This EquiTea session will explore mental health and suicide risk in academia, drawing on recent studies to spark discussion. We’ll reflect on risk factors and how institutions and universities can foster more supportive environment

Active galactic nuclei are powered by accreting supermassive black holes, surrounded by a torus of obscuring material. Recent studies have shown how the torus structure, formerly thought to be homogeneous, appears to be “patchy”: the detection of variability in the line-of-sight hydrogen column density, in fact, matches the description of an obscurer with a complex structure made of clouds with different column densities. In this talk, the multi-epoch analysis of 27 variable, nearby (z<0.1), Compton-thin active galactic nuclei (AGN) is presented. Analyzing all available archival soft and hard X-ray observations, we investigate the line-of-sight hydrogen column density (NH) variability on timescales ranging from a few days to approximately 20 years. We find that all sources require either flux or NH variability. Noticeably, there is no discernible difference between geometrical and intrinsic properties among the three variability classes, suggesting no intrinsic differences between the NH-variable and non-variable sources.

Prestellar cores represent the earliest stage of low-mass star formation. Their collapse under gravity is necessary for the ignition of young stars which evolve over time to eventually form Solar-like systems. However, the precise details of this collapse, including the initial conditions, is still not yet fully understood. Multiple dynamical models have been put forward to attempt to describe prestellar core collapse and we compare three of them in this talk: the LP, QE-BES and SIS models. We apply these models to a gas-grain chemical model in order to simulate the collapse of a prestellar core over time, thus developing a couple physico-chemical model. This particular chemical model is based on the UMIST Database for Astrochemistry reaction network, with additional reactions and species pertaining to deuteration our specific focus due to their particular suitability as tracers in the cold prestellar core environment. In this talk, I will present the initial findings of this project, which I am working on with Dr Evgenia Koumpia as part of the JAO Visitor Program.

Jets and disk winds arise from materials with excess angular momentum ejected from the accretion disk in forming stars. How these components are launched and how they impact the gas within the innermost regions of these objects remains vastly unknown. In addition, massive stars are typically detected as multiple systems, which could also have an effect on their disks’ structure and evolution. In this talk, I will present the results that we have obtained during my PhD. The first project consists on the modeling of Radio Recombination Line (RRL) masers observed with ALMA towards the massive star MWC 349A, which provide a very detailed picture of its ionized environment with a position accuracy down to a few AU scales. The ALMA observations of the H26α maser were taken in the most extended configuration of the array with a resolution of 0.02” that resolves the RRL emission for the first time. Our analysis with the 3D non-LTE radiative transfer model MORELI has revealed the existence of a high velocity ionized jet launched from the disk and engulfed within the ionized wind. Additionally, I will present our ongoing project that focuses on the study of the wind and jet of MWC 349A in the optical regime with the instrument MEGARA at the GTC. Last, I will briefly explain the work that I am currently doing during my visit to JAO, which consists in analyzing GRAVITY observations that will address the impact of binarity and ejection and accretion processes at small scales in a sample of massive young stellar objects.

In this talk, I’ll introduce a new, public code for performing isochrone fitting to the color-magnitude diagram of star clusters, named SIESTA (Statistical matchIng between rEal and Synthetic sTellar populAtions). In particular, I’ll show applications of the method in the context of the Large Magellanic Cloud, using data from the VISCACHA Survey, highlighting how determining reliable ages, metallicities and distances for star clusters within this galaxy is important for understanding some of its signature features, such as the age-metallicity relation and its 3-dimensional structure.

Understanding optical interferometric data is not simple, with visibilities and phases measured in Fourier space. PMOIRED is a python module which makes it simple to process and model interferometric data https://github.com/amerand/PMOIRED. The module is quickly becoming the standard in the interferometry community due to its flexibility and simplicity, being able to model a wide variety of systems and objects from stars, to disks, to AGN. The module is primarily for parametric modelling of astrophysical objects, but is also capable to taking outputs of hydrodynamical or radiative transfer models as inputs. In this way you extract physical spatial information from your Fourier observations without having to think in Fourier space. This talk follows from the lecture series given by Konrad (a theoretical introduction) and myself (a practical introduction), and will include examples and practice data sets.

Spectroscopic and photometric studies have identified massive quiescent galaxies (MQGs) at redshifts (z) greater than 2.5. An open and intriguing question is what processes led to the quenching and assembly of MQGs at z > 2.5, when the universe was only a few billion years old. My research investigates the impact of the environment on the quenching and assembly of MQGs at redshifts between 2.5 and 4.5. To address this, I am utilizing data from the One-hundred-square-degree DECam Imaging in Narrowbands (ODIN) survey. The ODIN survey uses Lyman-alpha emitters (LAEs) to trace large-scale cosmic structures, including overdensities, fields, voids, and filaments, across redshift slices of approximately 4.5, 3.1, and 2.4.

I am examining the correlation between the positions of MQGs and the filaments, protoclusters, fields, and voids identified in the ODIN survey. Additionally, I am conducting a comparative study of the physical properties of MQGs, LAEs, and Lyman-break galaxies (LBGs) within these various galaxy environments. To date, this represents the largest field study of MQG environments at z > 2.5. In this presentation, I will discuss the results of this unique study, focusing on the spatial distribution and physical properties of MQGs in relation to the large-scale structures in the ODIN fields, as well as the influence of environmental density on the evolution of MQGs.

Interferometry has made a spectacular entrance in the exoplanet field in the last five years with GRAVITY at the VLTI. By taking advantage of 100-meter baselines, interferometry can separate stellar and planetary signals at closer separations than direct imaging. Ultra-precise astrometry and medium-resolution near-infrared spectra were obtained on a dozen of substellar companions, enabling precise orbital fitting and atmospheric composition constraints. Since 2023, this technique has been extended to the mid-infrared with an upgrade to the MATISSE instrument. A new observing mode, GRA4MAT, makes MATISSE observations benefit from the GRAVITY fringe tracker, increasing MATISSE sensitivity and enabling off-axis pointing on faint companions. We demonstrated this new capability on the young giant planet β Pictoris b and obtained its first spectrum in L and M bands. During this talk, I will introduce what interferometry is bringing to the direct study of exoplanets, present these first MATISSE exoplanet observations, and outline the perspectives brought by the ongoing VLTI upgrade, GRAVITY+.

What makes some outreach materials or activities hit the mark while others fall flat? In this talk, we'll dive into content presentation, have open discussions, and reflect on our approaches. The goal is to help you think critically about designing outreach activities with clear objectives, so you can really see if your efforts are paying off.

The James Webb Space Telescope (JWST) marks the beginning of a new era for brown dwarf and exoplanet direct imaging, opening the parameter space to Saturn-mass planets. However, coronagraphs on board JWST are restricted to separations beyond 300-400 mas. The Aperture Masking Interferometry mode of the NIRISS Instrument overcomes this limitation, transforming the telescope into an interferometer. This enables high-contrast imaging down to separations of 100 mas, but is limited to bright stars. For fainter objects, clear-pupil imaging can attain similar performance thanks to Kernel Phase Interferometry (KPI), a generalization of interferometric techniques to regular images. KPI, combined with the exquisite stability of JWST at 4.8 um, represents a unique opportunity to search for planetary-mass companions around the coolest and faintest brown dwarfs, of spectral type Y. We use the publicly available JWST-KPI pipeline to analyze a survey of 20 Y dwarfs with JWST’s Near Infrared Camera (NIRCam). This program recently unveiled the first Y+Y binary, WISE-0336, whose two components, separated by 1 AU, could both have planetary masses, depending on their age. Our KPI analysis probes mass ratios down to 0.1, thus entering the sub-Jupiter mass regime, at separations as short as 0.5 AU. Altogether, these results show how KPI can be leveraged for high-contrast imaging below the diffraction limit, paving the way for future companion searches around faint objects with JWST.

During this lecture, we will address the legal status-quo of the Dark and Quiet Skies issue at hand. Through a brief overview of the legal landscape and the current discussions taking place at the Committee for Peaceful Uses of Outer Space (COPUOS) and the United Nations Office of Outer Space Affairs (UNOOSA) on the topic, we will delve into the current status of the clash of titans: satellite constellations and astronomy.

My intention is to provide an overview of the modelling work that I have been doing in the field of 3D model atmospheres. I will *not* dive into details of various projects but hope to provide sufficient information to stimulate meaningful discussion. Keywords are: solar photospheric abundances (recently silicon), extremely metal-poor stars (recently non-equilibrium formation of binary molecules), high-precision radial velocities (recently of wide binaries to test MOND), magnetic fields in solar-type stars (recently to study the center-to-limb variation measured in planetary transits by Kepler), and dating a bit longer back 3D models for white dwarfs, M-dwarfs, as well as Cepheid pulsators. What brought me to ESO Vitacura is my long-lasting collaboration with Luca Sbordone to learn about his analysis code MyGIsFOS with perspectives of its application in the 4MOST and perhaps PLATO projects.

This talk will introduce MAVIS - the Multi-conjugate adaptive optics (MCAO) Assisted Visible Imager and Spectrograph. MAVIS will pioneer the use of MCAO techniques at visible wavelengths, and will offer the highest possible resolution from a UT. MAVIS is presently in the final design stage and will replace GRAAL and HAWK-I on the UT4 Nasmyth A platform, with first light expected ~2030. We will provide a general introduction to MAVIS, highlight some key science cases and outline the strategies for the project implementation.

The study of metal-poor galaxies is crucial for understanding galaxy formation and evolution in their early stages. Most observational work in this field relies on photometry or long-slit spectroscopy. We present a novel approach using Integral Field Unit (IFU) data to analyze the biggest gas-phase nebula of the dwarf metal-poor galaxy SagDIG. We estimated the metallicity using the Te-sensitive method. Our analysis indicates that SagDIG is in line with a SFH which experienced momentum-driven winds from supernova (SN) outflows. The SagDIG HII-region exhibit a biconical structure, where young stars are located at the edges of the structure in a filamentary configuration, in line with those HII-regions observed in the milky way.

Are your students and colleagues using machine learning and it's all black magic? Then this Python coffee is for you! We will use the common sklearn machine learning package and go over the basics of two main applications of machine learning: clustering and prediction. Each will be introduced at a low level with one working example from the astronomy community. Given that I am also still a novice in the ML realm, this python coffee is meant as an interactive chat about machine learning, your applications of it, and the limitations it still has.

Carbon, nitrogen, and oxygen are abundant species that are found everywhere in the universe. Although the nucleosynthetic paths leading to their production in stars are crystal clear, we still miss a detailed, quantitative picture of CNO evolution in galaxies. In this talk I'll summarize what can be learned from CNO abundance studies. I'll discuss current uncertainties plaguing both theory and observations and I'll point to possible solutions.

The Euclid space telescope presents an exciting opportunity to delve into the processes which form and evolve galaxy clusters. An important aspect of the evolution of clusters is the formation of diffuse intracluster light (ICL) within cluster haloes, which offers an insight into a cluster’s dynamics and assembly history. Since ICL is very diffuse, detecting and quantifying it presents a challenge. I will demonstrate Euclid's transformative potential to constrain the evolution of the ICL fraction over cosmic time with unprecedented sample sizes and precision. We have been forecasting the limits with which Euclid will be able to detect ICL by analysing simulated clusters across a range of halo masses, redshifts and ICL parameters (fraction of ICL, effective radius, sersic index). We will explore ‘idealised’ signal-to-noise ratios for ICL detections across this parameter space in NIR H-band, and compare with results from different ICL fitting routines, in order to forecast the effectiveness with which Euclid will be able to detect ICL in future observations. We also estimate the expected sample sizes of clusters in which we will detect ICL across the Euclid Wide Survey.

The search for alien worlds has uncovered a surprising variety of planetary types, starting from gas giants in tighter orbits than Mercury's, then populating the apparent gap between rocky planets and ice/gas giants. Remote-sensing spectroscopic techniques have been developed to characterize the atmospheric envelopes of these objects, offering crucial insights into their bulk composition, structure, climate, and possible formation pathways. I will provide an overview of current methods for characterizing exoplanet atmospheres, including their challenges, state-of-the-art advancements, and key scientific discoveries. I will also highlight the synergies between these methods, with a particular emphasis on the complementarity of space-based and ground-based observations across different spectral resolutions.

ALMA is the largest radio interferometric telescope in the world and produces a vast amount of data every day. Several petabytes of data are measured, processed and stored in the ALMA Science Archive (ASA). Every data set has the potential for scientific results that go well beyond the ideas behind the original proposal, and a large fraction of these data remain unpublished and underutilized. In this talk, I will provide a brief overview of the Archive, different ways to access data, along with the current and future developments in science oriented data products.

In this session, we will explore the use of Galpak3D, a software tool designed to extract galaxy parameters and kinematics from three-dimensional data cubes. The algorithm directly compares the data with a parametric model mapped in spatial (x,y) and spectral (λ) coordinates, using a Markov Chain Monte Carlo (MCMC) method to return the intrinsic model properties. We will demonstrate this process with a MUSE data cube, finding the best-fit kinematic parameters and exploring various configurations to enhance these results. Additionally, we will discuss scenarios in which this software is particularly practical within extragalactic astrophysics.

In the study of active galactic nuclei (AGN), some sources have been extensively observed across various epochs and wavelengths. PMN J0948+0022 is one such source, exhibiting significant multiwavelength variability that has provided valuable insights into AGN structure and contributed to our understanding of this entire class. Initially classified as a jetted Narrow-Line Seyfert 1 (NLS1) galaxy, recent observations have revealed a different profile for the H-beta line, characteristic of Intermediate Seyfert galaxies. The variability primarily involves the narrow-line region of the AGN, although the broad-line region also shows notable changes. The proposed interpretation centers on the interaction between the narrow-line region and the relativistic jet. These findings offer new insights into the changing-look AGN phenomena, demonstrating how different AGN classes can be interconnected and enhancing our understanding of AGN evolution.

At the birth of the Solar System, asteroids and comets constituted the primary building blocks for the planets and moons we know today. Here, we share results from both ESO's MUSE instrument, used to characterise the atmospheres surfaces and ejecta from several dozen objects; and the Goldstone Radar array, used to create a morphological model of a contact-binary NEA. We have used MUSE to probe the exciting environments of 34 comets and 2 asteroids, from P106 to P113, which allowed us to infer properties of cometary nuclei and broad trends over different groups. Further, as reported in Murphy et al. 2023, we leveraged MUSE to support NASA's DART mission, which was the first successful planetary defence test, and aim to support more missions in the future. Additionally, we combined archival radar data collected at Goldstone in 2014 with optical lightcurves to create a comprehensive shape model of 2006 DP14, a NEA contact-binary.  These results will add to the small number of modelled contact binary objects and allow further research into the possible formation pathways of both this object, and similarly shaped objects such as Itokawa and the recently discovered Selam.

A precision of 10 cm/s in radial velocity (RV) is required to detect an Earth-like planet orbiting around a solar-type star. Although current state-of-the-art instruments are not far from this threshold, we still observe some residual signals of instrumental and stellar origin, that prevent us from reaching our goal. Those signals are difficult to disentangle and model directly on the RV time series, therefore we need to go back to the original spectra and correct them for perturbing effects before the actual RV extraction. That is a promising path to push further down the RV precision; in fact, we can rely on the exquisite Sun-as-a-star case to perform a thorough analysis of those residual signals and develop effective correction methods. During this talk, I will show preliminary results that demonstrate the power of such an analysis, significantly improving the RV precision. I will also put our results for the Sun into a wider context. Developing a robust method for extreme-precision RV extraction plays in fact a key role in the upcoming characterization of smaller and smaller planets. As first step of this process, we will apply and test our analysis on habitable zone Super Earth candidates.

TBD

We present extensive multi-wavelength optical and ultraviolet observations of SN 2022jli, an unprecedented Type Ic supernova. The multi-band light curves reveal many remarkable characteristics, facilitated by high-quality, high-cadence photometry, including a 12.5-day periodicity superimposed on the supernova decline. This periodicity, observed in the light curves across seven different filter and instrument configurations, has amplitudes of ~0.1 mag and persists over many cycles, this has not been previously seen in any supernova. SN 2022jli also displays an extreme early excess that fades over ~25 days, likely due to shock cooling or companion interaction. In this talk, I will present optical spectroscopic follow-up during the first 100 days, light curve and spectral modeling, and discuss the possible origins of the periodic variability in the light curve, including the interaction of the supernova ejecta with nested shells of circumstellar material (CSM) and a neutron star colliding with a binary companion. Additionally, I will present recent work on SN 2023zaw, where observations suggest a progenitor that has lost mass through envelope stripping by a neutron star companion.

Modern observational cosmology relies heavily on the calibration of standardizable candles in the local distance ladder, such as cepheids and type Ia supernovae (SNe Ia). However, these calibrations are often too simplistic and could potentially introduce systematics into our results, which have been cited as one of the possible explanations for the Hubble Tension.

In the case of SNe Ia, these systematics are further hinted at by the existence of the well-documented mass-step, a discrepancy between the calibrated luminosities of SNe Ia originating in high- and low-mass galaxies. The improper correction of dust extinction is one of the most likely sources for this effect, given that the standard correction assumes that all SNe are subject to dust with the same optical properties, which has been shown to be false. This could be especially relevant if different galaxy populations are subject to different dust types.

In this talk, I will discuss how to improve upon SN Ia calibration with a more in-depth dust correction. In particular, I will focus on the merits and demerits of using host galaxy dust data as a proxy for individual SN extinction.

The NOrthern Extended Millimeter Array (NOEMA) is one of the two mm observatories run by the Institut de Radioastronomie Millimétrique (IRAM) in Europe. The twelve 15 m NOEMA dishes make up the largest mm observatory in the Northern hemisphere, sitting at an altitude of 2552 m in the French Alps. It succeeds the Plateau de Bure Interferometer (PdbI) which was first constructed on the Plateau in the 1980s. In this talk I will briefly introduce IRAM and their work over the last decade to add 6 new antennas to the array. I will summarise the current and newly upgraded capabilities NOEMA including its sensitivity, extended array configurations and observing modes as well as ongoing, planned and possible future upgrades of the array.

Self-enrichment is one of the leading explanations for chemical anomalies in globular clusters. In this scenario, a certain polluter star, enriches a forming cluster with its yields, likely ejecting radioactive 26Al into its surroundings. Detection of 26Al in young massive star clusters holds significant implications, potentially supporting the self-enrichment scenario if these clusters are indeed progenitors of globular clusters. Recent advancements in observational techniques, including detections of the 1.8 MeV and 511 keV 26Al decay gamma ray lines, as well as 26AlF molecules or positronium radio recombination lines, suggest promising avenues for detecting 26Al and maturing detection methods.  In this talk, I will focus on examining a sample of young massive star clusters in the nearby Universe, where self-enrichment could plausibly occur. Despite optimistic scenarios, detecting most sources remains challenging with some methods. However, we identify R136 in the Large Magellanic Cloud as a promising candidate for such investigations. Although the best-case scenario for detecting a 1.8 MeV signal may require several years with instruments like COSI, the feasibility of detecting 26AlF with the ALMA telescope in several candidate clusters offers encouraging prospects for further study and understanding of self-enrichment scenario in young massive star clusters.

As an ESO astronomer with ALMA duties, much of my science is also ALMA-related. In the talk I briefly introduce my ALMA duties, the science I'm currently doing and have been doing, and my involvement in a possible new neighbour to ALMA called AtLAST: the Atacama Large Aperture Submillimeter Telescope. The current design is presented, and the wide range of science cases discussed, with a link to the future instrumentation required to realise the science goals.  AtLAST is meant to be complementary to ALMA. It will have a 2 degree field of view, which combined with the 50-m dish will make AtLAST the fastest, most sensitive, and highest resolution mapping machine of the sub-mm sky.

Since 2017, the GRAVITY interferometer at the VLTI has provided astrometric data with unprecedented accuracy of the S-stars orbiting around Sagittarius A*, turning them into a wonderful tool to investigate the gravitational potential around the supermassive black hole at the center of our Galaxy.  Specifically, we have been able to observe two effects predicted by General Relativity on the orbit of the star S2: the gravitational redshift of spectral lines and the in-plane, prograde Schwarzschild precession of the orbit's pericenter angle.
In this presentation, I will first discuss the progress we have made in detecting the Schwarzschild precession by continuing to monitor S2 and other S-stars with GRAVITY. Then, I will talk about the effect of an extended mass distribution around Sagittarius A*, primarily composed of a dynamically relaxed cusp of old stars and stellar remnants. Assuming the distribution follows a smooth, spherically symmetric density profile, it would introduce a retrograde precession of the stellar orbits, countering the prograde relativistic precession. I will present the upper limit obtained from S-stars data on the amount of extended mass that could lie within the orbit of S2, roughly in the central 10 milliparsecs of our Galaxy. This limit is compatible with the theoretical predictions for a stellar cusp in the Galactic center.
Finally, I will discuss the impact of the granularity of this stellar cusp, considering a scenario with a finite number of bodies that generate the mass distribution. This can lead to deviations in the orbital motion of stars compared to a smooth density distribution, causing precession of the orbital plane. Through numerical simulations, I aim to determine whether these deviations could affect our measurement of the Schwarzschild precession of S2.    

STARRED is a python package we developped to achieve precision photometry of blended point sources. But it is also more than a photometry package, I believe that STARRED is the best way of combining multiple epoch imaging data: just from repeated ground-based imaging, we unveil details way beyond the resolution of the orginal dataset. This will be particularly important when the realm of LSST will begin, as the capacity for high resolution imaging follow-up will be scarce compared to the number of targets ...but each will have hundreds of repeated ground-based observations!
I will first showcase a few examples of what STARRED can achieve. Then, we will walk through an introduction jupyter notebook, to:

• build a PSF model from a few cutouts of stars
• use the PSF model to simultaneously extract the photometry of another cutout while revealing very faint galaxies in the background.

Measuring the chemical composition of the ISM in galaxies holds significant importance in astrophysics, as it significantly influences stellar, galaxy, and cosmological evolution. According to the baryon cycle, the abundance of heavy elements should consistently rise over cosmic time, linking the metallicity of a galaxy to its evolutionary stage. Therefore, researchers have explored diverse relationships between metallicity and other galaxies’ parameters, such as mass and luminosity. Obtaining precise measurements of the ISM chemical composition is pivotal for accurately calibrate these correlations. Our study aims to investigate potential observational biases in the SEL method used to compute metallicities in faint, distant, and high-metallicity galaxies, focusing our attention on estimating the relevance of the DIG contamination and the influence of the aperture’s dimensions in the computation.

Sagittarius A* is the prime example of the existence of black holes. Precise stellar astrometry and spectroscopy have been used to observe both the gravitational redshift signature in the orbit of the star S2 and the prograde relativistic precession predicted by the Schwarzchild solution. Deeper in the gravitational potential, electromagnetic emission from a distance of a few gravitational radii has been detected at several wavelengths and resolved temporally and spatially in the Near Infrared. The feasibility of such studies makes SgrA* and its surroundings the best laboratory for studying gravity in the strong field regime. In this talk, I'll explain why and how we precisely track the motion of stars and gas around SgrA* and discuss the current joint theoretical and observational efforts employed by the GRAVITY collaboration to understand gravity ever closer to SgrA*.

Pulsars are rotating neutron stars that emit pulsating signals. They serve as valuable tools for studying a wide range of topics, from general relativity to the interstellar medium. The discovery of a pulsar in the Galactic centre (GC) would be particularly fascinating due to its proximity to the Sgr A*, the black hole at the centre of our Galaxy. Such a discovery could provide insights into the local environment and the nature of the black hole itself. In the GC, up to 1000 pulsars were predicted, but thus far only six have been found, including a magnetar. One of the explanations is that the dense environment in the GC causes extreme interstellar scattering, reducing the sensitivity of pulsar surveys. To improve our sensitivity to long-period pulsars, a Fast Folding Algorithm (FFA) was used rather than the traditional Fast Fourier Transform (FFT). In this talk, I will show results and discoveries of applying an FFA pipeline for accelerated pulsars to search for pulsars within 1$^\circ$ around GC using the data from the High Time Resolution Universe Pulsar Survey-South Low latitude as well as the three most sensitive stations from the Event Horizon Telescope observations of Sgr A* in 2017, including ALMA phased mode.

Although the eight major planets may be the celebrities of our celestial neighborhood, study of the minor planets provides diverse information about the formation and evolution of the Solar System. With over a million objects identified, distinct populations of small bodies (Main Belt asteroids, comets, and Kuiper Belt objects, to name a few) provide unique individual perspectives on planetary migration and accretion, and as such are an invaluable tool for understanding the origins of Solar- and Exo-planetary systems. In particular, binary asteroid systems allow for the remote determination of asteroid masses and densities, making them exceptionally good probes for the characterization of all small bodies. In this talk, I will present different methods for the discovery and characterization of binary asteroid systems, as well as potential formation mechanisms for asteroid satellites.

NumPyro is a probabilistic programming library that offers an interface for defining probabilistic models and running inference algorithms. After discovering the capabilities of JAX a few weeks back, you'll be pleased to know that NumPyro leverages JAX's auto-differentiation magic which allows us to close this loop. In this Python Coffee, we will explore how to use NumPyro to fit your data using Hamiltonian Monte-Carlo as well as Nested Sampling.

Studies of micrometeorites in mid-Ordovician limestones and Earth’s impact craters show that our planet witnessed a massive infall of ordinary L chondrite material ~466 million years ago that it believed to be at the origin of the first major mass extinction event (Schmitz et al. 2019). The breakup of a large asteroid in the main belt is the likely cause of this massive infall. In modern times, material originating from this breakup still dominates meteorite falls (~37% of all falls). I will present spectroscopic observations and dynamical evidence that we have identified the only plausible source of this catastrophic event and of the most abundant class of meteorites falling on Earth today.

TBD

While adaptive optics is the most widespread method to compensate for atmospheric turbulence, these methods are particularly difficult to implement in the optical regime given the technical challenges imposed by the short coherence times. An alternative to reach the diffraction limit of an optical telescope is provided by speckle interferometry, where, instead of real-time corrections, observations are obtained in timescales similar to the coherence time (a few ms), and the diffraction limit is recovered via a post-hoc reduction in Fourier space. In 2019, the Gemini telescopes commissioned two speckle interferometers, Zorro and 'Alopeke, owned by NASA Ames, which have remained as "permanent visiting" instruments since then. In this talk I will present the characteristics of these instruments, to then present a number of science cases where these instruments are particularly suited, mostly leaning to my own research on RR Lyrae in binary systems, and blue stragglers in hierarchical triplets

TBD

Nova eruptions in cataclysmic variables occur when enough material has been accreted onto the surface of the white dwarf. As a result, the accumulated material is expelled into the interstellar medium, forming an expanding nova shell around the system. Understanding the physical processes that shape the morphology of nova shells is essential to fully comprehend how the ejection mechanism works during nova eruptions. As part of the Apocalypse Programme, several nova shells have been observed with MUSE. The MUSE data, like all IFU data, contain a spectrum for each spaxel in the field of view. The aim was to convert these data into three-dimensional images in various emission lines, to explore the shell morphology further. In my talk, I will present how we developed 3D images that can be explored on a PC or VR setup.

A fundamental concept in observational astronomy is fitting complex models to data obtained from a multitude of instrumentation installed at a variety of telescopes. Such observations are accompanied by a convoluted array of noise sources imprinted on the obtained data. This together with the fundamental Poisson noise inherent to any data, makes model comparison even more challenging. Both parametric and non-parametric approaches to full noise consideration, such as wavelets and Gaussian Processes respectively, have been proposed.  I will present an example of how the consideration of the full covariance matrix, instead of just the variances, can lead to better estimation of precision and accuracy. Finally, I will go through some basic concepts of how this formulation can be implemented in a Bayesian framework in order to obtain posterior probability distributions, from which optimal parameter values and their uncertainties are estimated, using Markov Chain Monte Carlo simulations.

We present the results of a comparison between different methods to estimate the power of relativistic jets from active galactic nuclei (AGN). We selected a sample of 32 objects (21 flat-spectrum radio quasars, 7 BL Lacertae Objects, 2 misaligned AGN, and 2 changing-look AGN). We then calculated the total, radiative, and kinetic jet power by using both radio and high-energy gamma-ray observations, and compared the values. We found an excellent agreement between the radiative power calculated by using the Blandford & Königl model with 37 or 43 GHz data, and the values measured from the high-energy gamma-ray luminosity. The agreement is still acceptable if 15 GHz data are used, although with a larger dispersion. We also proposed some easy-to-use equations to estimate the jet power. 

MOONS is a 0.8–1.8-μm multi-object spectrometer designed to work at the Nasmyth focus of the VLT’s UT1. It will have 944 fibres patrolling a field 25 arcminutes in diameter. MOONS can be used with a spectroscopic resolving power R ~ 4000 spanning the full near-infrared wavelength range, or with R ~ 9000 in the I band and R ~ 18 000 in the H band. MOONS has two main sub-components, the rotating front end (which is at the focal plane and houses the fibre positioners, the acquisition system and the metrology system for the fibres) and the cryogenic spectrographs, which will be on the telescope’s Nasmyth platform. MOONS is now fully assembled at the UK-ATC, Edinburgh. PAE is expected this summer and it will arrive at Paranal by the end of the year. This talk will cover the science drivers behind the instrument and its current status.

I used to think Julia would be the language making Python writers obsolete, but that was before Google introduced JAX: I am now confident we will not be computationally old for at least a dozen more months. JAX is an autodifferentiable, just-in-time compiled framework which can run on CPUs, GPUs and more. Its Python interface is very similar to that of Numpy. We will fly over the following topics:

1. Automatic differentiation (realize how, ultimately, we'd probably be better off without it).
2. Optimizing when the gradient is for free.
3. Just-in-time compilation for blazing speeds.
4. Batching operations.

Being able to write modular functions, composing them together, and getting back a compiled, vectorized pipeline (and its gradient), all for free, unlocks a ton of possibilities. 

The Atacama Large Submm Telescope (AtLAST) is a community-driven initiative to build a 50m wide-field (sub)mm telescope. A 3.5 year design study funded by the European Union will be completed mid-2024, and has worked out several aspects of AtLAST: 1. the governance, 2. the telescope design, 3. the site selection, 4. the operations plan, 5. a sustainable energy provision and 6. the science cases. In this informal talk, I will present the current status of this design study. The telescope design allows for covering a field of view up to 2 degrees with fast switching, an active surface, regenerative braking for energy efficiency and solar observing capabilities. AtLAST will be able to host 6 instruments, including multi-chroic bolometer arrays, on-chip spectrometers and heterodyne arrays. I will also show the results from the site selection, resulting in two sites on Chajanantor to allow sharing of infrastructure with ALMA and other telescopes. AtLAST intends to cover a vast range of science cases including the Sun, solar system bodies, Galactic science, nearby galaxies, the circumgalactic medium, galaxy clusters and the high redshift Universe, as well as time-domain science. With 30% of the collecting area of ALMA and a full overlap in the uv-plane, AtLAST will be the ultimate total power complement to ALMA. Thanks to its 2 degree field of view, it will also be the ideal source finder for ALMA follow-up. The next steps for AtLAST are to set up a governance structure, further work out the telescope design and its suite of instruments, with the aim to have first light in the course of the next decade.

B[e] stars are massive, hot B-spectral type stars embedded within a dense dust circumstellar envelope. As a result, their continuous spectrum shows a strong infrared excess, forbidden and permitted optical emission lines. Because they constitute a vast and heterogeneous class of objects in terms of stellar evolution, from new born stars (Herbigs Ae/Be) to evolved stars (supergiants), B[e] stars are not yet very well understood despite a long history of observations (half of them still unclassified). For instance, recent observations indicate that supergiants showing B[e] characteristics can host circumstellar rings. So far, the main scenarios to explain the detection of a large amount of gas and dust, geometrically distributed in discs around the latter, are either due to decretion mechanisms, driven by radiative pressure, rotation, pulsation or mass transfer due to binary interaction. As the structure and dynamics of these discs are still unclear, the analysis of our high angular resolution observation campaigns conducted over 17 B[e] stars with the VLTI/MATISSE instrument between 2018 and 2021 will improve the general understanding over the mechanisms that drive phases of enhanced mass loss and mass ejections, responsible for the shaping of the circumstellar material of B[e] stars. Following the approval of a new observation proposal with VLTI/MATISSE, submitted during the ESO P112 call, the coverage of the interferometric aperture plane - commonly refered as the (u,v)-plane coverage - for eight stars of the survey has been enhanced, enabling an in-depth image reconstructions for those. The focus of this presentation will therefore lie on the multi-component geometric modelling and image reconstruction on the mid-infrared data of the supergiant A[e] star l Puppis, one of the targets of our current MATISSE B[e] survey. The results presented have been partially obtained through the ESO Early-Career Scientific Visitor Programme at ESO Santiago, Chile, during a collaborative period spanning two months with Claudia Paladini and Julien Drevon. Implications with regard to previous results obtained with the first generation interferometric instruments VLTI/MIDI and AMBER will also be explored.

Modern galaxy simulations routinely reach parsec resolution, thereby unlocking a more self-consistent treatment of the internal structure of GMCs while accounting for the galactic-scale gas flows. This has led to significant theoretical progress, particularly concerning the cycle between star formation and feedback, the multi-phase ISM, and galactic wind driving. The latest improvement is the advent of star-by-star models, enabling simulations including individual stars. My model INFERNO incorporates stellar feedback, chemical enrichment, and the natal velocities of individual stars in hydrodynamical simulations of entire galaxies. This alleviates many of the restrictions imposed by the traditional approach, e.g., when and where stars inject feedback. Furthermore, INFERNO incorporates a state-of-the-art chemical yield model with on-the-fly enrichment calculations for the majority of elements in the periodic table.

In my talk, I will present results from simulations of dwarf galaxies in cosmological environments where all observable stars are treated with star-by-star calculations throughout a Hubble time. I will focus on predictions for observations of faint galaxies in the Local Universe and how the chemical signatures of these galaxies can help constrain our models.

High-resolution observations with ALMA have revealed that concentric rings and gaps are common features in protoplanetary disks. A favored mechanism for creating these substructures is planet-disk interactions, in which growing planets open gaps in the disk, and particles become trapped at the pressure maxima that form at the corresponding gap edges. Since the particle density in these pressure bumps can become very high, they are likely sites for planetesimal formation via the streaming instability. I have studied the formation and fate of such planetesimals formed at planetary gap edges, and found that this process can have a dramatic impact on the evolution of solids in protoplanetary disks, and therefore also on how the disks appear in observations. I will present results from 1D hydrodynamical simulations and N-body simulations, as well as preliminary results from 3D hydrodynamical simulations.

Massive stars in star-forming regions inject huge amounts of energy and momentum into the ISM producing ubiquitous superbubbles, turbulent gas motions and outflows. The coupling efficiency of stellar feedback and its dependence on metallicity remains uncertain in simulations. Analysing the MUSE and HST observations from the PHANGS survey, we identified about 1500 expanding superbubbles and regions with local turbulent gas motions and linked them to the young star clusters. This allowed us to measure the coupling efficiency of mechanical stellar feedback and how it depends on the metallicity directly from the observations. In my talk, I will overview the current state of the PHANGS survey and focus on the measurements of the energy balance between massive stars and the ionized ISM in 19 nearby galaxies. 

Recent efforts in lensed quasar discovery — particularly with the use of Gaia — have provided an all-sky magnitude-limited sample of ~250 lensed quasars. I will discuss the most recent discovery techniques, present several interesting new systems and preliminary data from an HST Gap programme, and focus on an unexpected six-image system. HST imaging and NOT spectroscopy have shown that this is fact a dual quasar source with 6 kpc protected separation. I will discuss the implications of this single discovery for sub-10-kpc merger rates at Cosmic Noon. Finally I will discuss a possible milliparsec-separation lensed quasar pair, based on periodic signatures in a decade-long COSMOGRAIL lightcurve.

GitHub Copilot is an AI-powered code completion tool developed by GitHub in collaboration with OpenAI. It assists developers in writing code by providing contextually relevant suggestions as they type. Leveraging OpenAI's GPT models, Copilot analyzes the code context, including comments and variable names, to offer relevant code snippets, function calls, and even entire functions. GitHub Copilot offers code suggestions as you type, ranging from variable assignments to complete functions. Additionally, it allows interaction through natural language queries, generating code snippets based on descriptions. Copilot continuously learns from developer interactions, enhancing its suggestions over time. This discussion will delve into the installation process and effective utilization of GitHub Copilot, emphasizing its role in expediting code writing and enhancing efficiency. We'll explore how Copilot streamlines the development workflow, enabling developers to write code more swiftly and effectively.

The asymptotic giant branch (AGB) is the final stage in the evolution of low-to-intermediate mass stars, before they become white dwarfs. Experiencing strong convective dredge-up and slow pronounced dusty winds, AGB stars contribute a significant amount to the enrichment of the interstellar medium. The mass-loss process involved in this evolutionary stage is responsible for the formation of large dust and gas structures around such stars. So far, extended emission originating from such structures has mainly been observed in the infrared regime. However, recently more examples of emission associated with large scale features around AGB stars have been reported in the UV regime (Mira, CW Leo and RW LMi). This talk will focus on results based on a recent systematic Aladin survey of extended UV or IR emission structures associated with evolved AGB variables. The sample covers several extended features in GALEX FUV (far-UV 0.13 - 0.18 micron), ranging from very faint and barely visible structures to large, pronounced rings or bubbles with infrared counterparts. High quality UV observations of AGB stars and their surroundings are currently few in number, but results such as the ones of this study suggest that future observations focused on this wavelength regime could provide valuable information regarding the evolution of sun-like stars.

The European Southern Observatory's Paranal platform stands at the forefront of astronomical research, hosting a suite of sophisticated instruments capable of probing astronomical objects with a variety of technical solutions. In my presentation, I will guide you through the main characteristics of these instruments, and we will discuss their potential to serve your research interest.

M dwarfs are the most numerous stars in the solar vicinity, and play a key role in the hunt for habitable exoplanets. Those stars are known to host magnetic fields, with consequences both on planet detection and stellar characterization. In this talk, I present the results of a study aimed at detecting and quantifying the small scale magnetic fields of M dwarfs from high-resolution near-infrared (nIR) spectra. To this end we developed a new code, ZeeTurbo, by adding the Zeeman effect and polarized radiative transfer capabilities to Turbospectrum, and compute a homogeneous grid of synthetic spectra of magnetic stars from state-of-the-art MARCS model atmospheres. We fit our models to high-resolution near-infrared spectra to estimate the average magnetic field strength (< B >), effective temperature (Teff), surface gravity (log(g)) and metallicity ([M/H]) of M dwarfs. We applied our tools to 49 stars, including strongly and weakly magnetic targets, deriving < B > estimates consistent with previous studies. Those results can have implications for a broad range of fields, from the diagnostics of activity induced radial velocity jitters for the search of exoplanets, to the description of dynamo processes at the origin of the generation of magnetic fields in cool fully convective stars. ZeeTurbo provides the basis for ongoing and future projects aimed at studying magnetic fields of M dwarfs and pre main-sequence stars.

Dedoscopio is a 7 year project dedicated to achieve astronomical activities for blind and visually impaired people across Chile. We have learned how versatile astronomy is and, above all, how important learning through the 5 senses is. During the activity, we will talk about our experience in inclusive astronomy, showing the materials that have failed and those that have worked. We will have a moment for you to create tactile material, so we recommend arriving accompanied by all your imagination and all your skills to describe astronomical phenomena without using images.

Several recent studies have proven that the high-resolution spectroscopic analysis of young (t< 200 Myr) solar-analogues is rather complicated. The main culprit is activity, which presents in an intricate combination of relatively intense magnetic fields, presence of dark and bright spots on the surface and high levels of variability. All these contribute with significant variations of the strength (i.e., the equivalent width) of the atomic spectral lines, dramatically affecting, among other things, the derivation of the stellar parameters (mainly microturbulence velocity parameter) and the abundances of some elements (for example, barium and carbon). The times are now ripe to discuss and finally address these issues, given the importance of a precise stellar characterization for exoplanetary studies and to correctly interpret Galactic abundance trends. In this talk, I will revise our group's latest results in the spectroscopic analysis of young stars, presenting innovative techniques developed using stars in Galactic open clusters and new work(s) in progress.

Within Λ Cold Dark Matter simulations, Milky Way-like galaxies accrete part of their satellite galaxies in small groups rather than individually. It was suggested that this might be the reason behind the origin of satellite planes and the galaxy pairs found in the Local Group, providing new insights on dwarf galaxy formation and evolution. 

Objects accreted in groups are expected to share similar specific total energy and angular momentum, and also identical orbital orientations. Looking at observations of Milky Way satellites, the dwarfs Leo II, IV, V, Crater II, and the star cluster Crater 1 were proposed to be a vestige of group infall. The suggested "Crater-Leo group" shows a monotonic distance gradient and all these objects align along a great circle.

To further investigate this possibility, we use Gaia Data Release 3 and present new Hubble Space Telescope (HST) proper motions to derive accurate orbital properties for these objects. Assuming that satellites accreted as a group share similar specific angular momentum and total energy, we can identify possible associations and predict their proper motions.

Leo II, Leo IV, and Crater 1 show orbital properties consistent with those we predict from assuming group infall. However, our results suggest that Crater II was not accreted with the rest of the objects. If confirmed with increasingly accurate proper motions in the future, the Crater-Leo objects appear to constitute the first identified case of a cosmologically expected, typical group infall event.

The fate of a massive star during the latest stages of its evolution is highly dependent on its mass-loss rate and geometry. The geometry of the mass-loss process can be inferred from the shape of the circumstellar material, having a significant influence on the evolution of massive stars (25 and 40 Msun), i.e., type II SN progenitors. In this context, yellow hypergiants (YHGs) offer an excellent opportunity to study mass-loss events.

This talk will focus on recent results on two members of this class, IRAS 17163-3907, the central star of the Fried Egg nebula and IRC +10420. I will present the analysis of optical and near-infrared data with the main focus on the observed spectroscopic and interferometric (GRAVITY/VLTI) modes. Our VLTI/GRAVITY K-band interferometry on both sources reveals that the neutral Na I 2.2 μm line emitting region is smaller than that of the hydrogen Brγ emission. We perform LTE modelling demonstrating that this observation can be explained with the hydrogen emission being the result of collisional excitation populating the higher levels in a neutral region instead them being populated through recombination in an ionised environment as mostly inferred in stellar winds. In addition, our geometric models towards IRC+10420, reveal an evolution of the ejecta over only about 7 years, while our 2D radiative transfer modelling towards IRAS 17163-3907 led to the discovery of a third hot inner shell with a maximum dynamical age of only 30 yr. For this yellow hypergiant, we find three observed distinct mass-loss episodes which are characterised by different mass-loss rates and can inform theories of mass-loss mechanisms, which is a topic still under debate both in theory and observations. These will be discussed in the context of photospheric pulsations and wind bi-stability mechanisms.

The Bayesian Analysis of Galaxies for Physical Inference and Parameter EStimation (Bagpipes): a customizable tool for spectral modeling. In this session, we will explore the Bayesian Analysis of Galaxies for Physical Inference and Parameter EStimation (Bagpipes) Python package. This is a useful code for modeling spectra and also fitting photometric and spectroscopic observations. Computations made in the code are based on successful theoretical models on (i) stellar populations, (ii) dust emission, (iii) nested sampling algorithm, and (iv) photoionization models. Additionally, due to its flexibility and customization to work with different data, Bagpipes is a common tool in the exploration of star-formation histories and their consequences in observational works in the last four years. We will learn how to do SED fitting to photometric data, spectroscopic fitting, and reproducing spectra with custom parameters and star-formation histories.

X-ray binaries allow us to measure the mass of the compact object through the motion of the secondary. High-mass X-ray Binaries (HMXBs) with black holes of masses up to ~20 solar masses for the famous Cygnus X-1 have been discovered so far, whereas more massive stellar mass black holes have solely been detected through gravitational wave radiation in black hole mergers. Aiming to find a more massive stellar mass black hole in a HMXB, we observed the source IGRJ16479-4514 which shows similarities to Cygnus X-1. This eclipsing HMXB has the shortest orbital period known of ~3.3 days and additionally contains an O supergiant donor star. We use time resolved X-shooter spectroscopy in the near-infrared to determine the mass of the compact object. Perhaps surprisingly, we find a mass of no more than ~2 solar masses for the compact object with which we classify it as a neutron star. In this talk I will discuss the analysis leading up to the mass determination of the compact object and the O star.

Band 1 is offered for Science Observation starting in Cycle 10. The process of integration/acceptance will be presented, as well as the science goals of this receiver.
Band 2 preproduction receivers, the first wide band, have been produced, installed, and tested in the ALMA system. The project has been accepted in the Main Readiness Review (2023), and the production receivers are under construction. Integration is expected to start in the second half of 2024. I will describe the technical aspects of these new receivers, the foreseen plan of integration, as well as their scientific capabilities.

Note: This is the second talk in a talk series. In this series of two talks, Dr. Marconi will describe the commissioning process of the ALMA band receivers with a special focus on Bands 1, 2, and 5, while giving an overview of the science goals that can be achieved.

Peer review is the backbone of scientific research. It has a strong influence on the progress of science, careers of researchers, allocation of resources (including telescope time, computation, and billions of dollars), and the public perception of science. It is therefore of vital importance to understand the blindspots in peer review and improve it in a principled manner. With this motivation, this talk will comprise two parts: In part 1, we will present insightful experiments that shed light on key aspects of peer review. In part 2, we will discuss the design and deployment of algorithms to address problems in various parts of the review process. No prior knowledge will be assumed. The talk is partly based on the survey article https://www.cs.cmu.edu/~nihars/preprints/SurveyPeerReview.pdf

Strong gravitational lensing is a well-established tool to constrain models of galaxy evolution, the nature of dark matter and cosmological parameters. Fundamental to these lines of research is the parameterisation of the large-scale mass distribution of the lensing galaxies, which have long been assumed to be well-described by a singular ellipsoidal power-law density profile with external shear. However, the inflexibility of this model could lead to systematic errors in astrophysical parameters inferred with gravitational lensing observables. In this talk, I will present observations with the ALMA of three strongly lensed dusty star-forming galaxies at 30 mas angular resolution and our investigation of the sensitivity of these data to angular structure in the lensing galaxies. Using multipole expansions of the power-law density profile up to fourth order, l show that all three data sets strongly favour third and fourth-order multipole amplitudes of ≈1 percent of the convergence. I compare the isodensity and isophotal shapes of these galaxies, and find that two of them have significant disagreement. I discuss the contributions to the angular structure from dark matter intrinsic or extrinsic to the lensing galaxy and the implications for this for future lensing studies.

The Rubin management team visiting ESO will review the Vera Rubin Observatory project and current status. Rubin is in the final stages of the Construction phase and is anticipated to transition to operations in less than 1.5 years from now.  We intend to review the main science goals as well walk through the complexity of the Data Management System and the operations workflows.  Additionally we will provide some lessons learned from our contract with INRIA who designed and built our LSST Operator’s Visualization Environment (LOVE) system.   

I will describe how the new receivers are commissioned, accepted, and offered for science use after the science verification. As ESO band 5 was the first ADP provided to ALMA, I will discuss how it was managed and the experience gained to improve the process itself.

Note: This is one of the two talks in a series. In this series of two talks, Dr. Marconi will describe the commissioning process of the ALMA band receivers with a special focus on Bands 1, 2, and 5, while giving an overview of the science goals that can be achieved. 

W2246-0526 is a Hot Dust Obscured Galaxy (Hot DOG) at redshift 

4.6, and the most luminous obscured quasar known to date. I will present 

ALMA observations of this Hot DOG for the brightest far-IR 

fine-structure emission lines, as well as of their underlying dust 

continuum. A comparison of the data with a large grid of CLOUDY 

radiative transfer models reveals that the conditions of the 

interstellar medium of the galaxy need to be extreme: high hydrogen 

density and extinction, together with intense ionization and a high 

X-ray to UV ratio, among the largest found in the literature. This (and 

future planned) work sheds light on the extreme conditions that galaxies 

can experience during the early stages of the Universe, a piece of 

information that is critical to our understanding of how distant and 

young galaxies evolve.

The MeerKAT Fornax Survey has successfully observed the central part of the Fornax cluster with an unprecedented sensitivity and resolution. Reaching a M(HI) sensitivity of ~10^6Msun, these data allow us to investigate the low HI mass population of the Fornax cluster.
The simple question of whether the faint HI emission is a free floating cloud or a faint galaxy would remain unanswered without the availability of deep optical images. By analysing deep VST optical images from the Fornax Deep Survey, it is now clear that some of the low-mass HI detections do not have an optical counterpart and are thus clouds of gas floating within the ICM. 
Finally, I will also mention the studies on the SFH and the properties of the multi-phase gas of Fornax galaxies that are possible thanks to the availability of MUSE, ALMA and APEX data. In particular, I will focus on the case of NGC 1436, a lenticular galaxy in the making.
Multi-wavelength analysis, which are able to provide a snapshot of the current evolutionary state of a galaxy as well as to provide information about its past interactions, are powerful tools to shed light on the physical processes which have driven galaxy evolution.

Small planets located at the lower mode of the bimodal radius distribution are generally assumed to be composed of iron and silicates in a proportion similar to that of the Earth. However, recent discoveries are revealing a new group of low-density planets that are inconsistent with that description. Their low densities could be explained by a scarcity of iron within their cores, by the presence of a significant amount of volatile elements, or by both effects. Recently, Adibekyan et al. found that stars with higher Mg/Fe and Si/Fe ratios host lighter super-Earths, which indicates a compositional star-planet connection. However, the lowest-dense super-Earths cannot be explained by having an iron-poor core, and instead require a significant amount of volatile elements in their compositions. The reason why those planets have such large amounts of volatiles is still unknown. In this talk, I will present our recent characterization of the unusually low-density super-Earth TOI-244 b based on ESPRESSO and TESS data and discuss its possible composition. Besides, I will present two tentative trends in the density-metallicity and density-insolation parameter space that might hint at the formation and composition of the lowest-density super-Earths.

At first it was a challenge of scientific communication, now it is a way of life. Making science accessible to people with disabilities holds a potential that goes beyond social responsibility or empathy. It is also about making diversity an integral part of scientific development, incorporating people full of curiosity with new approaches to face problems. 


We propose to start by revising our own perception of disability, giving people with disabilities and people involved in their education and caretaking the opportunity to tell us about it, and by opening our minds to new ways of doing science. Inclusive astronomy drives us to be creative, to generate networks, and to collaborate in an interdisciplinary way. We hope that this initiative will extend to other areas of scientific research.

Recent advancements in distance measurement techniques have unveiled
discrepancies in the estimation of the Hubble parameter between early
and late Universe indicators. Additionally, non-negligible disagreements
have emerged in the Hubble parameter values derived from near-Universe
indicators, such as Cepheids and the Tip of the Red Giant Branch (TRGB).
Thus, the establishment of new, independent, and reliable distance
estimation methods provides an important sanity check.
In this context, Type II supernovae have remained an underutilized
resource. Their relatively straightforward physics, combined with recent
advancements in modelling techniques, make it possible to estimate
precise distances without relying on the calibration ladder. Apart from
describing the potential of Type II supernovae as a dependable distance
measurement tool, I will also showcase it by presenting the results of
two recent empirical tests described in
        Csörnyei et al. 2023a,
https://ui.adsabs.harvard.edu/abs/2023A%26A...672A.129C/abstract  and
        Csörnyei et al. 2023b,
https://ui.adsabs.harvard.edu/abs/2023arXiv230513943C/abstract
Both of these initial tests yield encouraging results, showing that
obtaining a high-precision value for H0 through Type II supernovae alone
is indeed possible.

The 5-sigma tension between the measurement of the Hubble constant based on the CMB and that based on a local distance ladder with Cepheid stars and Type Ia supernovae has turned into one of the most pressing problems in modern cosmology. If the discrepancy is real and not just due to underestimated measurement uncertainties, it hints at new physics beyond the cosmological standard model Lambda-CDM. To address this problem, additional measurements of the Hubble constant, ideally completely independent of the local distance ladder, are essential. Strong gravitational lensing can provide such a measurement: time delays between the multiple images in strong-lens systems can be used to determine the "time-delay distance", which is inversely proportional to the Hubble constant. The method has already been successfully applied to strongly lensed quasars, supporting a physical origin of the Hubble tension. Here, I describe the efforts of the HOLISMOKES team to extend the method to strongly-lensed supernovae, which have several advantages over lensed quasars. So far, the progress is restricted by the extreme scarcity of lensed supernovae and the limited depth of present-day sky surveys. However, with upcoming deep surveys such as LSST or Euclid, hundreds of new time-delay lenses will make lensed-supernova time delays a competitive cosmological probe with the prospect to shed light on the true origin of the Hubble tension.

Two of our summer internship students, Claudia Rodrigues (PUC) and Fernanda Vera (UdeC), will present the results from their summer internship at Paranal and Vitacura conducted in January and February. Claudia has been working on a new tool to predict contamination from background sources during observations of Solar System moving objects (asteroids and comets). Fernanda has developed a code to monitor skyflats count levels in real time for ERIS on UT4.

Gas-phase metallicity and its spatial distribution hold the signature of the processes that shape the build-up and evolution of galaxies. Different radial profiles of metallicity can be interpreted in terms of either inside-out galaxy growth, radial mixing, galaxy mergers, or (re-)accretion of chemically enriched or pristine gas.
Conflicting theoretical predictions and heterogeneous observational results exist for gas metallicity gradients at high z. Moreover, observations have probed metallicity gradients only up to z~2-4 until very recently, before the advent of JWST.
I will present gas-phase metallicity gradients in three systems at z~6-8, when the Universe was only <1 Gyr old and the galaxy assembly was vigorously taking place. By making use of JWST NIRSpec IFU observations, we mapped the ionised gas in several rest-frame optical emission line diagnostics. We find generally flat radial gradients of gas metallicity, which are consistent with these sources being experiencing frequent mergers and gas mixing. These results extend up to z~8 the regime in which metallicity gradients are explored, providing a critical reference to inform models of galaxy evolution.

Arp 220 represents the closest prototypical ultraluminous infrared galaxy (ULIRG) in an advanced phase of major mergers.  This study leverages the NIRSpec@ JWST to unravel the intricate kinematics within the nuclear region of Arp 220.
Thanks to integral field data and NIR observations, we can penetrate the dust enshrouding the nuclear region, enabling a detailed exploration of Arp 220's nuclear environment. This work focuses specifically on the complex kinematics of Arp 220, with a detailed examination of both stellar and gas kinematics across various phases, encompassing ionized and molecular states.
Employing Gaussian multifitting techniques, we disentangle the complex kinematic components within the nuclear region of Arp 220. Through decoupling processes, we isolate contributions from disc rotation, outflows, bubbles, streams and filaments due to the merging, confirming the previous scenario of two counter-rotating nuclei with a rotational disc observed at larger scale.
Clear signatures of the presence of AGN have not been detected.
Our analysis reveals the presence of a high-velocity bubbles emerging to the western nucleus originated from shock. We also show the presence of extended outflow from the eastern nucleus both in ionized and molecular gas, also detected at larger scale with MUSE.

Since the beginning of its operation, the Optical Gravitational Lensing Experiment (OGLE) survey has made significant contributions to various astronomical fields. In my talk, I will provide a brief overview of the project's history, outlining our current observing capabilities and strategies. Additionally, I will present our latest results, including, findings from microlensing and other transient events, as well as research on variable stars. Finally, I will discuss my involvement in the OGLE project, including the recently published catalog of highly probable transiting planetary candidates in Galactic Bulge observational fields. Furthermore, I will detail my analysis of two microlensing events that exhibited pronounced planetary anomalies

The formation processes that lead to Giant exoplanets on close-in orbits around their host stars are still debated; (i) in-situ formation theories provide too little explanations for planets with Jupiter-masses, which can be easier explained through (ii) formation on further-extended orbits, migrating to close-in orbits. Different migration mechanisms could lead there, pushing Giant planets either to circular and aligned orbits (in “dynamically cold” formation pathways) or to eccentric misaligned orbits (in “dynamically hot” formation pathways). However, so close to their host star, these planets experience strong tidal interactions, leading to a circularization of their orbits. For Hot Jupiter-type planets (here defined as p < 10 days), these circularization timescales are much shorter than for Warm Jupiters (10 d < p < 200 d), for which these timescales exceed the time since their formation. Therefore, the current day architectures of Warm Jupiters can provide valuable insights into their formation processes.

One observable that can be used to distinguish between the different mechanisms, is the obliquity angle which measures the alignment between the stellar rotation axis and the planetary orbital angular momentum, which is obtained through the measurement of the Rossiter-McLaughlin (RM) effect. Currently, the obliquities of ~200 planets have been observed, ~150 of which are Hot Jupiters; the numbers of Warm Jupiters with known obliquities are much lower, due to observational limitations. In this student internship project, we attempted to increase the number of Warm Jupiters by 6 (with 9.28 days < p < 28.38 days) using high-precision spectroscopy observations with ESPRESSO. Using the publicly available code ARoME code, we model the RM effect effect, obtaining obliquity angles for these targets, assuming uncorrelated white noise only.  However, beyond the studentship, these results will be published where the analysis will include a correlated noise component using Gaussian Processes and stellar activity indicators as regressors, with the aim of showing the importance of their inclusion in such analysis. The posterior distributions and uncertainties of the model parameters were sampled with Monte Carlo Markov Chain (MCMC) simulations. Here, we can present the best-fit results for the fitted parameters of 5 Warm Jupiter systems.

Gamma-ray bursts (GRBs) have been an active area of research since their serendipitous discovery in the 1960s. Despite this, the physics and nature of their progenitors are still poorly understood. Whilst GRBs have multiple formation channels, they are all thought to be produced by relativistic outflows. Constraining the properties of these jets could be the key to understanding these highly energetic events. GRB 221009A and its afterglow are thought to be consistent with a structured jet. In this regime, we can predict a population of short-timescale, GRB afterglows many times larger than the GRB population. Previous surveys lacked the cadence necessary to probe this theoretical population. However, the Deeper, Wider, Faster Programme’s (DWF) deep, wide-field and fast-cadenced dataset is uniquely suited to a search of this kind. Using DWF data collected with the Dark Energy Camera, mounted on the Victor M. Blanco telescope, we conduct an untargeted search for GRB afterglows. This search will constrain the parameter space that GRB jets inhabit and shed light on the mysteries of GRB progenitors.

It is now commonly accepted that the dusty ‘tor0us’ in AGNs is a more complex structure than a simple toroidal distribution, roughly composed of an equatorial dusty disc and polar dusty wind launched by radiation pressure at the inner disc. However, this picture is primarily based on studies of moderately accreting Seyferts. As the accretion rate increases, the radiation pressure will also increase, changing the orientation and structure of the wind. To study the effect of Eddington ratio on this structure, we examine the wind launching region in two high accretion rate objects, I Zw 1 (super-Eddington) and H0557-385 (high-Eddington), using high spatial resolution interferometric observations in the KLM-bands using VLTI/MATISSE and VLTI/GRAVITY. We recover wavelength-dependant sizes using a Gaussian fit to the visibility. Both objects are partially resolved have sizes in the KLM-bands between 0.4 – 1.0 mas, with no position-angle dependent elongation. Combining our measurements with VLTI/MIDI N-band data gives a full multi-wavelength picture of the dust structure. We find that in H0557-385 the sizes of the dust measured at different wavelengths between 3.5-8 um are independent of the wavelength, constant at 10Rsub. We argue that this indicates a direct view of the wind launching region, and together with an absence of polar elongation, indicates the wind is launched in a preferentially equatorial direction. I Zw 1 shows a homogeneous dust distribution at the inner disc, and little mid-IR contribution, implying the presence of a puffed-up inner disc. We conclude that there is a strong suggestion the Eddington ratio shapes the inner dust structure, foremost the the wind-launching region, and therefore impacts the larger dust structure.

I will present an excursus of current and future medium-size facilities at ESO, and highlight their role in the astrophysical research of the last century. In the process, I will discuss some milestones of ESO history, and show how the organisation is evolving the role of its 4m-class telescopes in the near future.

Ultra-hot Jupiters (UHJs) are gas giant exoplanets on close-in orbits around their host stars with equilibrium temperatures of T > 2000K. The relatively strong emission signals from their daysides make these objects favorable targets for high-resolution spectroscopic characterization. This method has led to the discovery of lines from a wide range of chemical species and significant Doppler shifts in the spectra of UHJs, allowing measurements of atmospheric composition, thermal structure and dynamics.

My talk will focus on high-resolution spectroscopy of UHJs with CARMENES (Calar Alto Observatory) and CRIRES+. I will present the results of a recent in-depth characterization of WASP-33b with CARMENES. This study revealed the presence of several novel chemical species in the planet's atmosphere and provided evidence for the presence of strong atmospheric dynamics. Finally, I will give an overview of ongoing projects on gas giant exoplanet atmospheres in the CRIRES+ instrument consortium.

TBD

ALMA is an incredibly versatile facility that provides mm-wave images down to sub-arcsecond resolution, as well as total power (single-dish) images sensitive to larger scales. Complementary observations with the baseline array and Morita Atacama Compact Array (ACA) are vital for recovering the true flux distribution of spatially resolved astronomical sources accompanied by extended emission. This talk will be based largely on Plunkett et al. (2023), which provides an overview of the prominent available methods to combine single-dish and interferometric observations. I will describe a suite of test cases and assessment tools used to evaluate data combination methods. Finally, I'll introduce publicly available scripts, enabling participants to perform their own data combination and ensure high-quality science images of spatially resolved objects.  This presentation itself will *not* be hands-on for the participants, but you are welcome to bring some data that you are working on so that we can talk about options for data combination.

AGN feedback and its consequences on overall galactic evolution have been, for a time now, at the forefront of the field, with a clear picture yet to emerge. I will introduce the challenges and opportunities that Lyman Alpha emission presents in active galaxies at high redshift. Additionally, I will discuss how it can be used to identify and characterize galactic scale outflows as well as their overall impact on their hosts through recent MUSE observations of powerful radio galaxies.