Seminars and Colloquia at ESO Garching and on the campus

The enigmatic journey of massive black holes, from the formation of a seed population in the early universe to their subsequent growth and mergers represents a vastly multi-scale phenomenon deeply intertwined with the process of galaxy formation. In this talk, I discuss the insights gleaned from cutting-edge cosmological simulations. These simulations not only provide some clues into the elusive population of Intermediate Mass Black Holes (IMBHs) but also shed light on some of the largest black holes in our Universe.

The stars evolving through the asymptotic giant branch (AGB) are generally regarded as highly efficient dust manufactures, owing to the thermodynamic properties of their wind, which prove extremely favourable to the condensation process of gas molecules into solid grains. In this review I will describe the dust and mineralogy of the dust  formed in the surroundings of this class of stars, outlining the role of mass and metallicity, and the importance of these studies for the characterization of evolved stellar populations in galaxies. The contribution from the analysis of the spectral energy distribution of post-AGB stars towards a better understanding of the dust formation process by AGB stars will be also commented on.

ALMA observations of Betelgeuse in 2023 reached a resolution of ~8 milliarcsec – the highest to date. The continuum results show long-lived hotspots on the surface, and a photosphere of this supergiant which is clearly not spherical. In molecular lines, clumpy emission and absorption can be imaged from just above the photosphere. Comparing the results with data taken ~9 years previously suggests that these structures are rather long-lived – not what has been predicted from some theoretical models.

Two new lines from Rydberg transitions of Hydrogen and heavier elements were discovered, and I describe how these transitions can be used to study the atmosphere of this star.

At bands 9 and 10, ALMA can potentially reach 4-5mas resolution, and I describe what science could be possible with this – the highest resolution observations of stellar photospheres possible until ELT and ngVLA are built.

After decades of being mostly confined to the local Universe, the study of gas dynamics in galaxies, via a variety of emission-line gas tracers, has now become a key tool of investigation across cosmic time. The rotation of the gas allows us to trace the distribution of matter, quantify the mass and shape of the dark matter halos and study galaxy scaling relations. At the same time, gas turbulence reveals the effects of stellar feedback and disc instabilities and provides clues on the formation of the stellar thin/thick discs. I will present results on high-z rotation curves and velocity dispersions obtained through 3D reconstruction techniques of the emission-line datacubes. I will focus on ALMA observations of galaxies at z~4-5 observed in [CII] emission lines, extending to intermediate redshifts (z=1-4) using mostly CO lines. These data reveal fast rotation and relatively-low gas velocity dispersions leading to typical V/sigma values of order 10, similar to those of nearby spiral galaxies. Often, the fast rotations show the presence of mass concentrations that suggest a quick formation of stellar bulges, while the low velocity dispersions indicate that the gas turbulence is mostly fed by supernova feedback. I will discuss how the widespread presence of such “cold” discs at z~4-5 and their properties are changing our understanding of galaxy formation at early times.

With its unique combination of enormous light gathering power and unprecedented spatial resolution (thanks to state-of-the-art adaptive optics), the ELT is set to revolutionise observational astrophysics.  HARMONI – the ELT’s integral field spectrograph - will provide spatially resolved spectroscopy of a wide variety of astronomical sources, ranging from solar system objects to the most distant galaxies ever observed.  Extremely sensitive medium resolution spectroscopy will open new ways of understanding the physical processes throughout the history of the Universe. By using line strengths and ratios, together with Doppler shifts, HARMONI observations can deduce the morphology of the kinematics, chemical composition, and physical characteristics (density, temperature, etc.) at high angular resolution.  The talk will showcase some of the salient observations where HARMONI@ELT can have a huge impact, together with work on simulations that will tie the observations with detailed physical understanding of the evolution of galaxies over cosmic time.

Ground-based resolved imagery of asteroids has seen a remarkable growth over the past decade, essentially due to the availability of high-order correction adaptive optics systems like Sphere at the VLT. Such observations transitioned from supporting in-situ space missions to establishing themselves as stand-alone science programs aiming at searching for the presence of asteroid moons and informing us about minor bodies geology, collisional history, and surface and internal composition.
In this talk, I’ll briefly review the progress made over the past decades, focusing on recent precise determination of asteroids shape and density, and how this information helps us constrain the core-surface compositional gradient of these bodies and how they collisionally and dynamically evolved since their formation. 

I'll introduce a new class of radio objects, the Odd Radio Circle (ORCs). You'll learn why they're odd; how far away they are; and some ideas for what may produce them, based on recent optical spectroscopy.

I will present recent results from the mm-Wave Interferometric Survey of Dark Object Masses (WISDOM), a high resolution survey of molecular gas in galaxy nuclei. First, I will show that CO can be used to easily and accurately measure the masses of the supermassive black holes (SMBHs) lurking at galaxy centres. In particular, I will highlight the latest measurements, that spatially resolve the SMBHs’ spheres of influence with a few tens of resolution elements, thus leading to very precise measurements. Second, I will introduce SMBH mass-independent metrics to compare molecular gas and megamaser measurements. In turn, I will show that molecular gas observations now probe the same region of the SMBHs’ neighbourhoods, and that the mass measurements are now equally competitive. Third, if time allows, I will introduce the newly-discovered "mm fundamental plane of black hole accretion", that is surprisingly tight and holds for a wide variety of active galactic nuclei and stellar-mass black holes. This work opens the way to both precise and numerous SMBH mass measurements across the Hubble sequence (in both active and non-active galaxies) with a unique method, and thus promises to revolutionise our understanding of the co-evolution of galaxies and black holes.

The frequency of gas giants versus their mass and orbital separation, as a function of host mass, provides a powerful test of planet formation theory.  With a large database of point estimates of planetary mass companion occurrence rates, covering orbital separations 0.3 to 300 AU, and masses 0.3 to 30 Jupiter masses, we combine data from surveys of M dwarfs, FGK, and A stars, to search for global trends.  To accurately assess the planet population, it is vital that very low mass brown dwarf companions are considered as a separate population.  We also search for dependence of critical planet parameters on host star mass.  We have used this model to interpret direct imaging surveys and identify a local maximum in the gas giant planet orbital distribution.  Here we present an update which fits the gas giant planet populations of M, FGK, and A stars as a log-normal orbital distribution with a peak between 3-6 AU (68 % confidence interval) and recovers the power-law mass function (dN/dq ~ q-1.3) consistent with many other studies.  We compare our results to predictions of planet formation theory.  Finally we discuss our model in the context of new Y dwarf surveys with JWST, recent discoveries around high mass stars in Sco Cen, as well as characterization spectra of wide-orbit companions. 

The Poisson-Boltzmann theory stems from the pioneering works of Debye and Onsager and is considered even today as the benchmark of ionic solutions and electrified interfaces. It has been instrumental during the last century in predicting charge distributions and interactions between charged surfaces, membranes, electrodes, macromolecules, and colloids. The electrostatic model of charged fluids, on which the Poisson-Boltzmann description rests and its statistical mechanical consequences have been scrutinized in great detail. Much less, however, is understood about its probable shortcomings when dealing with various aspects of real physical, chemical, and biological systems. After reviewing the Poisson-Boltzmann theory, I will discuss several extensions and modifications to the seminal works of Debye and Onsager as applied to ions and macromolecules in confined geometries. These novel ideas include the effect of dipolar solvent molecules, finite size of ions, ionic specificity, surface tension, and conductivity of concentrated ionic solutions.

Near-infrared interferometry is a unique tool to study the inner sub-parsec structure of AGN which is inaccessible with current single dish telescopes. With VLTI/GRAVITY, we can now spatially resolve not just the hot dust continuum on milliarcsecond scales through imaging but also the broad-line region on microarcsecond scales through spectro-astrometry. In this talk, I will review the latest results from our observations of local AGN with GRAVITY where we have mapped the kinematics of the BLR in seven nearby AGN, measured sizes of the hot dust for sixteen AGN, and reconstructed images for two AGN. BLR kinematics have allowed us to independently measure the BLR size and supermassive black hole mass where we begin to find a departure from the radius-luminosity relation at high luminosity. I will give an overview of the GRAVITY+ upgrades that will allow for direct black hole mass measurements out to high redshift and therefore a precise tracing of supermassive black hole-galaxy coevolution through cosmic time.  With the addition of wide-angle off-axis fringe tracking during the first phase of GRAVITY+, we have already pushed observations out to cosmic noon. I will show initial results from this program, including the first dynamical black hole mass measurement at high redshift which reveals an undermassive black hole that is accreting at super-Eddington rates.

The study of high-z clusters and protoclusters is fundamental to understanding the connection between the evolution of galaxies and their environment. Theoretical models of galaxy formation and evolution are still challenged by observations of a highly diverse star formation scenario in (proto)clusters at z~2, confirming that the physics of galaxy formation is not well understood yet. This cosmic time is characterized by the transition from highly star-forming protoclusters to mature clusters, and its study is a fundamental step in constraining our knowledge of galaxy evolution. Cosmological hydrodynamical simulations are currently among the most advanced tools to investigate this. I will present the analysis of a set of state-of-the-art high-resolution cosmological hydrodynamical simulations of galaxy (proto)clusters and compare them with an average cosmological volume, acting as a "control field", to isolate the effects of environment on galaxy populations. Monte Carlo radiation transfer of stellar light through a modeled dust distribution was included in post-processing in order to enable a proper comparison with the observed properties of (proto)cluster galaxies. I will show how the simulations succeed in reproducing some observables related to the star formation and dynamics of galaxy populations, while others remain a challenge, leaving questions open on which key ingredients are still lacking in our theoretical framework.

The Young Suns Exoplanet Survey (YSES) is a direct imaging search for young self-luminous gas giant exoplanets around one Solar mass stars in Sco-Sen. I will talk about our discoveries of three exoplanet systems found so far from our intial sample of 72 stars, the latest results that we have in the analysis of these planets with separations of 100 to 700 au, and discuss the possible formation and evolution scenarios. I will also introduce our follow up survey extending our sample to another 150 young one solar mass stars, called the Wide Sepration Planets in Time (WiSPIT) survey where we propose to test formation mechanisms for these planets by looking at detection rates as a function of time from 1 Myr to 15 Myr.

In 2021 a young, solar type star underwent a complex series of eclipsing events that lasted over 900 days, preceeded by an infrared brightening seen in NEOWISE photometry some 1000 days prior to the optical eclipse. We propose that this is evidence for a collision event between an ice giant exoplanets and another exoplanet in the system, forming a luminous remnant called a `synestia’ surrounded by an expanding and cooling cloud of debris that caused the later optical eclipse. We show that Cycle 3 JWST spectroscopy will be able to confirm our models for the glowing remnant and surrounding cooler dust cloud, and discuss the implications for planet formation and evolution.

Giant radio galaxies (GRGs) are radio galaxies (RGs) with a projected extent larger than 700 kpc and they play a crucial role in shaping our understanding of the evolution and dynamics of radio galaxies (RGs). In this presentation, I review the lifecycle of RGs, focusing on the distinct properties of GRGs. I present a multi-wavelength study of approximately 1600 RGs, including 280 GRGs, identified in the Low Frequency Array (LOFAR) deep fields. I discuss differences in host galaxy properties, environment, and evolutionary stages between GRGs and smaller RGs.

The analysis reveals insights into the interplay between jet power and host galaxy mass, shedding light on the mechanisms driving the formation and evolution of GRGs. Additionally, I explore environmental properties using the number of neighboring galaxies within 10 Mpc as a proxy, uncovering distinctive environmental properties of GRGs compared to smaller RGs (< 700 kpc). Integrated flux densities and radio luminosities were also determined for a subset of RGs through available survey images at 50, 150, 610, and 1400 MHz to compute integrated spectral indices. The findings of this analysis demonstrate that GRGs not only represent the largest RGs in the universe but also serve as key indicators of the advanced stages of RG evolution.

Accretion disks are common in astrophysical systems, from AGN to protostellar disks. The disks of Be stars (rapidly rotating Main Sequence B-type stars) are special: they are discretion disks, built from matter ejected by the central object. When in a binary system, the companion can affect the Be disk in many ways, exciting density waves and even causing truncation. It can also accrete material from it, as is the case for Be X-ray binaries, whose X-ray emission is powered by accretion onto a compact companion. In our work we simulate Be binaries with a smoothed particle hydrodynamics (SPH) code (Okazaki et al. 2002) in order to investigate the effects of the companion on the dynamics of the disk, the process through which it accretes matter, and how the system loses mass as whole. We employ a modified version of the code, specially updated by us to increase resolution in low density areas of the system, such as the outer disk and around the companion. We find that disks are formed around the secondary in all models, but viscosity, mass ratio and period play a significant role in their structure and kinematics. A circumbinary disk is formed around the system for all simulations, which was never before seen in simulations for coplanar, circular Be binaries, but agrees with recent observational findings of radio emission from these types of system, where an ad-hoc circumbinary disk model was employed. Our study paves the way for a better understanding of X-ray emission in Be X-ray binaries, and offers an insight in how hidden companions of Be stars can be detected observationally.

The Northern Light has been inspiring awe in humans for millennia. We mostly see three colors of light dancing in the sky: Blue aurorae at 428 nm coming from excited N2, Green aurorae at 557.7 from atomic oxygen, and red aurorae mainly at 630 nm also due to atomic oxygen. Interest in the polarization of the northern light started in 1959, but the reported measurements were quickly disputed and the results were deemed unreliable. Interest in this topic has been low, until 2008, when they again observed the red line of the Aurora and found a significant signal. However, this and the following polarization measurements of the other lines lacked spatial information. In this talk, I will present measurements of the polarization of the Aurora with our new compact instrument which can do RGB linear polarization measurements. I will discuss the main obstacles we faced, solutions such as adding an additional halfwave plate, and a preliminary view of the latest results.

Supernova remnants (SNRs) drive large-scale shocks that locally enhance the density of the surrounding material but also inject vast amounts of energy and momentum that largely perturb and disperse the Interstellar Medium (ISM). The interplay between these two effects is considered paramount in regulating the star formation efficiency in galaxies. However, how SNRs affect the physical conditions of the ISM is not well constrained from an observational point of view. In this talk, I will present our work aimed to address this question. I will show our study of the large scale shock triggered by the SNR W44 on the molecular cloud G034. I will show how the shock, probed by Silicon Monoxide (SiO) and observed with ALMA, enhances the density of the processed gas to values compatible with those required for massive star formation and has helped to shape the cloud. I will also present our exploratory large single-dish observing program SHREC, aimed to observe the molecular shock tracer SiO(2-1) toward a sample of 30 SNRs known to be interacting with molecular clouds. I will introduce the aim and technical aspects of SHREC and present the first results obtained toward the SNRs IC443. IC443 is a well known SNR, expanding into and interacting with a nearby toroidal molecular cloud. Toward the major site of interaction, known as clump G, we estimate the mass of the shocked gas to be 100 Msun. The shock driven by IC443 into this material enhances its density by a factor >10, to value consistent with those required to ignite star formation. Finally, we estimate up to 40% of the momentum injected by IC443 is transferred to the nearby molecular material. Our work therefore indicates that the molecular ISM is an important carrier of the SNR momentum and that the SNR-molecular cloud interaction play a crucial role in the regulating star formation in galaxies.

Stellar-mass black holes (BHs) are unique objects to constrain stellar and star cluster initial conditions and evolution, as they encode valuable information on their short-lived progenitor stars. If a significant fraction of BHs receive negligible natal kicks at birth, they can be retained even in open clusters with low escape velocities.

In this talk, I will present the first search for BHs in the closest open cluster to the Sun, the Hyades. I will show that the exquisite measurements by Gaia, combined with accurate N-body models, now give us the opportunity to infer signatures of even few BHs in open clusters, from the imprints they leave on the cluster’s stellar populations. For the Hyades, the observations are best reproduced by models with 2-3 BHs at present, while those that have never possessed BHs cannot match the cluster mass and size simultaneously. I will discuss how this result can provide key information on the BH natal kick distribution, one of the most crucial but still unconstrained aspects of BH formation.

Moreover, I will characterize the populations of BH-star binaries in open clusters. I will explore possible candidate stars with a BH companion in the Hyades, based on their excess error in the Gaia single-source catalog but high membership probability. Finally, I will investigate if dynamical interactions in young and open clusters can trigger the formation of Gaia BHs.

The birth of stars and the formation of galaxies are cornerstones of modern astrophysics. While much is known about how galaxies globally and their stars individually form and evolve, one fundamental property that affects both remains elusive. This is problematic because this key property, the birth mass distribution of stars, referred to as the stellar initial mass function, is a key tracer of the physics of star formation that underpins almost all of the unknowns in galaxy and stellar evolution. It is perhaps the greatest source of systematic uncertainty in star and galaxy evolution. The past two decades have seen a growing variety of methods for measuring or inferring the initial mass function. This range of approaches and evolving definitions of the quantity being measured has in turn led to conflicting conclusions regarding whether or not the initial mass function is universal. Here I review this growing wealth of approaches, and highlight the importance of considering potential initial mass function variations, reinforcing the need to carefully quantify the scope and uncertainties of measurements. I present a new framework to aid the discussion of the initial mass function and promote clarity in the further development of this fundamental field.

Future and ongoing infrared and radio observatories such as JWST, METIS, and ALMA will increase the amount of rest-frame IR spectroscopic data for galaxies by several orders of magnitude. While studies of the chemical composition of the interstellar medium (ISM) based on optical observations have been widely spread over decades for star-forming galaxies (SFGs) and, more recently, for active galactic nuclei (AGN), similar studies need to be performed using IR data. In the case of AGN, this regime can be especially useful given that it is less affected by temperature and dust extinction, traces higher ionic species, and can also provide robust estimations of the chemical abundance ratio N/O. Moreover, regarding (Ultra)-Luminous Infrared Galaxies ([U]LIRGs), the IR regime peers through their dusty medium and allow us to include the obscured metals in their studies. In this contribution, I will provide a summary of the bayesian-like code HII-CHI-Mistry-IR, which takes advantage of photoionization models, characterized by the chemical abundance ratios O/H and N/O, and the ionization parameter U, to compare their predicted emission-line fluxes with a set of observed values. Instead of matching single emission lines, the code uses some specific emission-line ratios that are sensitive to the above free parameters. I will also review our most recent findings from the study of IR emissions, starting from the performance of the code and its comparison to optical studies, following by a discussion on the universality of the S/O chemical abundance ratio, which can be independently estimate thanks to the set of emission lines available in this regime, and ending up by the finding of deviations from the mass-metallicity relation (MZR) as a consequence of the action of massive inflows of metal poor gas that produces that some galaxies experience a "deep-diving" phase in the MZR diagram as the metals from their ISM are diluted. 

A third of all massive stars are predicted to lose their hydrogen-rich envelope through mass transfer or common envelope ejection initiated by a binary companion star. As a result, the hot and compact helium core is exposed. These "stripped stars" are the direct progenitors of hydrogen-poor supernovae and merging binary neutron stars, but they are also so hot that they should boost the ionizing output from bursty star-forming galaxies.

Despite their importance, stripped stars remained, until recently, observationally unconfirmed since their predicted existence over half a century ago. We found the first set of stripped stars by combining ultraviolet and optical photometry with follow-up spectroscopy in the Magellanic Clouds. By fitting their spectra with a new grid of models, we could measure stellar properties and thus confirm that the predictions from binary evolution models are broadly consistent with observed stripped stars.

This discovery is a step towards understanding the role of interacting binaries in stellar populations. This is evidenced, for example, by the highly ionized gas surrounding some of these systems, shining brightly in O III and Balmer spectral lines. Directly constraining the ionizing emission and hardness of stripped stars, along with the typical gas density surrounding the stars, could lead to estimates of the escape fraction for different star types and the disentangling of stellar populations in unresolved galaxies.

I will present one of the most recent climate simulation results regarding the potential collapse of one of Earth’s most prominent tipping elements: the abrupt collapse of the Atlantic meridional overturning circulation (AMOC). AMOC is a system of ocean currents that brings warm water north and cold water south in the Atlantic. Its potential collapse could lead to abrupt cooling of the Northern Hemisphere, changes in tropical rainfall patterns, and non-linear changes in sea-level rise in the North Atlantic. Using the Community Earth System Model, Van Westen et al. (2024) simulated the first AMOC tipping event due to ocean freshwater forcing from Greenland Ice Sheet melt. From their results, they developed a physics-based and observable early warning signal of AMOC tipping. Atmospheric reanalysis products indicate that the present-day AMOC is on route to tipping, but current time series measurements do not allow us to predict when this abrupt transition might occur. Abrupt transitions occurring due to climate change might have a dramatical impact on ecosystems and living organisms on our planet.

Van Westen et al., Sci. Adv., 10, 6, 2024

Circumstellar disk dispersal is a brief, yet critical, end stage of disk evolution, dictating the end of planet formation and migration. Thermal winds powered by high-energy stellar photons have long been theorized to drive disk dispersal. However, evidence for these winds is currently based only on small (~3-6 km/s) blue-shifts in [Ne II] 12.81 um lines, which does not exclude MHD winds. We report JWST MIRI MRS spectro-imaging of T Cha, a disk with a large dust gap (~20 au in radius) and known blue-shifted [Ne II] emission. We detect four forbidden noble gas lines, [Ar II], [Ar III], [Ne II], and [Ne III], of which [Ar III] is the first detection in any protoplanetary disk. After performing continuum and PSF subtraction, we discover a spatial extension in the [Ne II] emission off the disk continuum emission, consistent with a disk wind. In contrast, we also find compact [Ar II] emission.

We then show how by applying photoionization radiation transfer to simple hydrodynamic wind models we can predict the extent and luminosity of the Ne and Ar line emissions. Along with the low degree of ionization implied by the line ratios, we find that the relative compactness of [Ar II] compared to [Ne II] implies a dense wind such that soft X-rays and EUV only reach the inner parts of the wind while harder X-rays ionize the wind to larger radii. This requires high mass-loss rates (~10^-8 Msun/yr) and small wind launch radii (~1 au), that are consistent with the properties of X-ray-driven photoevaporation.

These high mass-loss rates suggest that we may be witnessing the last stage in T Cha’s disk evolution, which is supported by the serendipitous discovery of a significant change in the continuum consistent with a depletion in the mass of the inner disk.

HARPS is one of the most long-lived and proficient instruments installed at ESO telescopes. During 20 years of operation, it has produced about 800 thousand spectra, half of them of astrophysical sources and the other half of the Sun. These observations have been of paramount importance in advancing the understanding of stellar phenomena and discovery of exoplanets.

A first critical review of the observations of astrophysical sources was published in the ESO Archive as HARPS Radial Velocity catalog. This allows archive users to access the radial velocity of the targets and identify the spectral types observed, expanding the RV content using the Halpha line for RV determination.

In this talk, I will discuss the process of associating these observations with SIMBAD identifiers, a key step in cataloging and analyzing this vast dataset, and I will show how the resulting HR diagram from the HARPS RV catalog facilitates the identification of stars based on their physical characteristics.

I will also present the plan for producing a high-resolution high signal-to-noise stellar library and offer some insights into the chemical/physical and temporal characterization of this dataset.

This past summer, the pulsar timing array community announced strong evidence for the presence of a stochastic background of nanoHertz frequency gravitational waves. This has been the primary goal of the community for the past two decades, and it took thousands of hours of telescope time, over 500,000 pulse arrival times from ~70 millisecond pulsars, and a highly sophisticated and very computationally demanding analysis effort to accomplish. While we can't yet say for certain what is causing the gravitational waves, our best guess is a population of slowly merging super-massive black hole binaries throughout the universe. But it is possible that the signal also heralds new physics. So what does it all mean and what are we expecting next? And what other cool things can we do with all of this high-precision pulsar data?

Paper: https://arxiv.org/pdf/2304.01757.pdf

The chemical evolution of distant galaxies, unlike nearby galaxies, cannot be assessed from observations of individual stars. On the other hand, the study of the interstellar medium (ISM) is an alternative way to reveal important properties of the chemical evolution of distant galaxies. The outcome of the evolutionary history of galaxies is recorded in the interstellar abundances of the chemical elements. Observations of the interstellar medium (ISM) in galaxies of various types, which differ in mass, size, metallicity, and are at different evolutionary stages, can provide a key to understanding the processes taking place in galaxies.I will present the study of the abundance patterns of the neutral ISM in 110 gas-rich mostly-metal-poor distant galaxies (Damped Lyman-alpha absorbers, DLAs) at redshifts 0.60 < z < 3.40. We observe systematic deviations from the basic abundance patterns for O, Mg, Si, S, Ti, and Mn, which we interpret as alpha-element enhancements and Mn underabundance.  We constrain for the first time the distribution of the alpha-element enhancement with metallicity in the neutral ISM in distant galaxies. Less massive galaxies show an alpha-element knee at lower metallicities than more massive galaxies. If this collective behaviour can be interpreted as for individual systems, this would suggest that more massive and metal-rich systems evolve to higher metallicities before the contribution of SN-Ia to [alpha/Fe] levels out that of core-collapse SNe, possibly explained by different SFR in galaxies of different masses. Overall, our results add important clues to the study of chemical evolution of distant galaxies.

The activity of the Sun and solar-like stars is driven by a dynamo mechanism, according to which the combination of differential rotation and convective motions of the outer atmospheric envelope continuously regenerates the magnetic field that manifests itself in the form of powerful optical, UV, and X-ray radiation. M-L dwarfs are also known to be magnetically active, but the physical mechanism is poorly understood. Studying their X-ray emission and its variability with rotation and stellar parameters allows to constrain the dynamo mechanism that powers the magnetic field and causes activity in the atmosphere.

In this talk, I present our attempt on constraining the magnetic dynamo of M dwarfs by studying the mass-dependent activity-rotation relation for the largest and most uniform sample of M dwarfs with observations taken with XMM-Newton, Chandra, eROSITA, K2 and TESS combined with X-ray and rotation data from the literature. Finally, I will present the relation between the X-ray and radio luminosity of ultracool dwarfs, and the evidences of a previously proposed bimodal dynamo responsible for the magnetic activity of these objects.

Found to be among the most dark matter-dominated systems discovered to date, low-mass galaxies provide stringent tests of our cold dark matter model on small scales. Because they are intrinsically faint and difficult to identify and characterize, studies thus far have primarily focused on the population of dwarf galaxies orbiting the Milky Way. I will present novel observations of low-mass galaxies beyond our local galactic neighbourhood, uncovering their considerable diverseness and introducing new astrophysical puzzles. I will describe a new framework for obtaining constraints on the distribution of dark matter in low-mass galaxies by leveraging their globular cluster systems and dynamical considerations. I will also present new constraints on the statistical mapping between satellite galaxies and their host dark matter halos, utilizing a unique sample of satellite galaxies in the Local Volume from the ELVES survey. I will conclude by discussing ongoing and future surveys essential in mapping the census and properties of the general population of low-mass galaxies.

Pressure broadening is one of the general line broadening processes in astrophysics. Indeed, it is widely used to model spectra from stelar and exoplanetary atmospheres, where the gas pressure is significantly high. However, its effect has been ignored in the field of planet formation. In this talk, we show that pressure broadening can affect line emission with high optical depths, even under a typical condition of the inner ~10 au region of protoplanetary disks, which produces very broad line wings. By taking advantage of this phenomenon, we can directly measure the gas pressure and density, which is otherwise a very difficult task. Indeed, we found that the CO molecular line spectrum from the nearest protoplanetary disk around the young star TW Hya has a very broad line wing, which is characteristic of pressure broadening. We successfully derived the gas density profile and found that the disk is gas-rich and a promising site for planet formation.

The magnetic field is one of the critical segments of the interstellar medium. It has been proposed that supporting interstellar clouds against gravitational collapse by magnetic fields could explain the low observed star formation efficiency in the Milky Way and other galaxies. Planck satellite provided a 5-15' all-sky map of the magnetic field geometry in the diffuse interstellar medium. However, higher spatial resolution observations are required to understand the transition from diffuse gas to gravitationally unstable gas. The Flame Nebula, also known as NGC 2024, is located in the Orion B molecular cloud and provides an excellent opportunity to study the role of the magnetic field in the formation, evolution, and collapse of filaments, as well as the dynamics and effects of young HII regions on the surrounding molecular gas. NGC 2024 contains a young, expanding HII region and a dense filament that harbors embedded protostellar objects. In this talk, I will present the results of our recent work on analyzing the magnetic fields in the Flame Nebula. We use new SOFIA HAWC+ 154 and 216 micron dust polarization measurements and the CN and HCO+ emission as part of the IRAM 30-m ORION B large program. In this work, we determine the geometry of the magnetic field and estimate the strength of its plane of the sky component across the NGC 2024. The magnetic field in NGC 2024 follows the morphology of the expanding HII region and the direction of the main filament. The derived plane of the sky magnetic field strength is moderate, ranging from 30 to 80 micro G, with the strongest measured at the east edge of the HII region, whereas the weakest field is found toward the filament in NGC 2024. We have found that the magnetic field has a non-negligible influence on the gas stability at the edges of the expanding HII shell and the filament, a site of the current star formation.

The Large Hadron Collider (LHC) offers a unique opportunity to probe the dark matter sector by producing dark matter particles in high-energy proton-proton collisions. Although such particles are invisible to an LHC detector, once produced, they can reveal themselves through their interactions with the known particles of the Standard Model. The LHC has developed a comprehensive dark matter search program, covering various collision signatures, such as large missing energy, resonant signals from new mediator particles, or invisibly decaying Higgs bosons. More recently, experimental techniques have advanced to probe also extended or strongly-interacting dark sectors, that would result in unconventional long-lived or novel hadronic signatures. A review of recent collider dark matter searches, their interplay and interpretations will be presented.

Where and how stars form within galaxies are two of the most critical questions in galaxy evolution. Our understanding of the star formation process is limited, ultimately, by our understanding of the sites of individual star formation — giant molecular clouds (GMCs). These dense, gaseous structures have sizes of 10s of pc, so the high spatial resolution required to resolve them has been mostly unattainable beyond the Local Group before the advent of the ALMA interferometer. Even then, acquiring the statistical sample of these ‘cloud-scale’ observations to answer questions like how local environment (bars, rings, etc.) module the star formation process has been an undertaking requiring 100s of hours of observing time with dedicated teams.

I will present some new results from the mm-Wave Interferometric Survey of Dark Object Masses (WISDOM) project looking at the properties of molecular clouds in ‘red and dead’ early-type galaxies, attempting to understand why these often molecular gas-rich galaxies do not form stars. We find that the molecular gas in these galaxies is often not in virial equlibrium, and external forces such as shear are likely destroying the clouds on shorter timescales than required for star formation to occur. The gas in these galaxies may be analogous to those in the Central Molecular Zone (CMZ) of the Milky Way, and provide an excellent laboratory for studying the interaction between extreme dynamics and cloud-scale properties. Combining ALMA with MUSE optical inteferometry, I have also been studying star formation on a resolved level in these quiescent galaxies. Star formation appears to be extremely localised to very small regions of the galaxy, and our integrated star formation rate measurements may be severely biased by this, with the true SFR being maybe an order of magnitude lower. However, resolved star formation efficiencies are similar to that of star forming galaxies, indicating that when star formation does happen, it perhaps happens in the same way across the galaxy population. 

I will give an introduction to the structure and dynamics of the central 3 kpc of the Milky Way. This region hosts a complex star-forming ecosystem that is continually exchanging matter with the rest of the Galaxy through inflows and outflows. The Galactic bar efficiently transports gas from the Galactic disc towards the centre at a rate of ~1 Msun/yr, creating a ring-like accumulation of molecular gas known as the Central Molecular Zone (CMZ) at a radius R=120pc. The CMZ is the local analog of the star-forming nuclear rings commonly found at the centre of external barred galaxies, and forms by a process similar to the one that creates gaps in Saturn’s rings. Once in the ring, approximately 10% of the gas is consumed by its intense star formation activity. Star formation does not occur uniformly throughout the CMZ ring, but is more likely to occur near the sites where the bar-driven inflow is deposited. The star formation rate of the CMZ varies as a function of time, but it is currently debated whether this is due to an internal feedback cycle or to external variations in the bar-driven inflow rate. The radius of the CMZ gas ring slowly grows over Gyr timescales, and its star formation activity builds up a flattened stellar system known as the nuclear stellar disc, which currently dominates the gravitational potential of the Milky Way at 30pc<R<300pc. Most of the gas not consumed by star formation in the CMZ is ejected perpendicularly to the plane by a Galactic outflow powered either by stellar feedback and/or AGN activity, while a tiny fraction continues moving radially inward towards the circum-nuclear disc at R=few pc, and eventually into the sphere of influence of the central black hole SgrA* at R<1pc.

• From 11:00 to 12:30
• From 13:45 to 15:00

Paper: https://arxiv.org/abs/2310.08052

An ESO internal ALMA development study, BRAIN is addressing the ill-posed inverse problem of image analysis employing astrostatistics and astroinformatics [1,2]. These emerging fields of research offer interdisciplinary approaches at the intersection of observational astronomy, statistics, algorithm development, and data science [3]. In this study, we provide evidence of the benefits in employing these approaches to ALMA image analysis for operational and scientific purposes. We show the potentials of two techniques (RESOLVE [4,5] and DeepFocus [6]), applied to ALMA calibrated science visibilities. Significant advantages are provided with the potential to improve the quality and completeness of the data products and overall processing time. Both approaches evidence the logical pathway to address the incoming revolution in data analysis dictated by ALMA2030 [7]. Moreover, we bring to the community additional products through a new package (ALMASim) to promote advancements in these fields, providing a refined ALMA simulator usable by a large community for training and/or testing new algorithms.

[1] Guglielmetti, F. et al. "Bayesian and Machine Learning Methods in the Big Data Era for Astronomical Imaging" Phys. Sci. Forum 2022, 5(1), 50; https://doi.org/10.3390/psf2022005050

[2] Guglielmetti, F. et al. ?A BRAIN Study to Tackle Image Analysis with Artificial Intelligence in the ALMA 2030 Era? Phys. Sci. Forum 2023, 9(1), 18; https://doi.org/10.3390/psf2023009018

[3] Siemiginovska, A. et al. "Astro2020 Science White Paper: The Next Decade of Astroinformatics and Astrostatistics", arXiv 2019, arXiv:1903.06796

[4] Junklewitz. H. et al. "RESOLVE: A new algorithm for aperture synthesis imaging of extended emission in radio astronomy", A&A, 586, A76 (2016)

[5] Tychoniec, L. et al. "Bayesian Statistics Approach to Imaging of Aperture Synthesis Data: RESOLVE Meets ALMA" Phys. Sci. Forum 2022, 5(1), 52; https://doi.org/10.3390/psf2022005052

[6] Delli Veneri, M. et al. "3D detection and characterization of ALMA sources through deep learning", 518, 3 (2023); https://doi.org/10.1093/mnras/stac3314

[7] Carpenter, J.; Iono, D.; Kemper, F.; Wootten, A. "The ALMA Development Program: Roadmap to 2030", arXiv 2020, arXiv:2001.11076

Recent discoveries of accreting brown dwarfs (BD) and exoplanets that appear to accrete at anomalously high rates have placed new importance on understanding the mechanisms that control their growth and formation. I will discuss my work to disentangle systematic effects from true physical variation in substellar accretion properties using the Comprehensive Archive of Substellar and Planetary Accretion Rates (CASPAR). CASPAR consists of >1000 measured Ṁs from ~800 T-Tauri stars, BDs, and planetary mass companions (PMC), making it the largest compiled sample of Ṁs for accreting objects to-date. I will show that systematically rederiving physical and accretion properties for all objects in the database has a negligible effect on the scatter in the M-Ṁ relation while showing that the remaining broad scatter is attributable to physical effects such as age, mass, and variability.

The DSA-2000 will be a world-leading radio survey telescope and multi-messenger discovery engine, commencing construction in 2025. Building on proven technology developed for DSA-110, the array will consist of 2000 x 5m dishes instantaneously covering the 0.7-2 GHz frequency range, spanning an area of 19 km x 15 km in Nevada. In an initial five-year survey, the DSA-2000 will image ~33,000 deg2 repeatedly over sixteen epochs, producing a combined full-Stokes sky map with 500 nJy/beam rms noise and 3.3 arcsecond spatial resolution. Fundamental questions surrounding the baryon cycle in galaxies, the formation of stars over cosmic time, and the influence of active SMBHs on galaxies, will be addressed by detecting over a billion star-forming galaxies and active SMBHs, and by observing the neutral-hydrogen kinematics and contents of several million galaxies. The array will revolutionize the field of radio transients, detecting >10,000 FRBs, >10,000 pulsars and >1 million slow transients, with sub-arcsecond localization for host galaxy identification. The DSA-2000 will also be a leading instrument for the discovery and characterization of the electromagnetic counterparts to neutron-star mergers found by ground-based GW detectors. Overall, it will thus also serve as the radio counterpart of the Rubin-LSST survey.

There has been a tremendous leap forward in our understanding of the formation of planetary systems thanks to substantial advances in our observational capabilities. Observatories like ALMA are routinely revealing the presence of complex structures in the gas and dust which are forming planets, much of which has been associated with young, embedded protoplanets. Such observations are unpinning sigificant developments in the theory of how, and from what, planets form. In this talk I will provide an overview of our current understanding of the physical, chemical and dynamical structure of protoplanetary disks with a particular focus on how we are beginning to detect the presence of young planets, only recently formed. I will present new results from the exoALMA program, an ALMA Large Program that is undertaking an extensive planet-hunting campaign in the sub-mm, and the related projects on facilities like JWST, VLT and Magellan. To conclude, I will discuss future facilitiies, and detail how, in the coming decade, we will begin to push into the terrestrail planet forming regions of these disks and understand the formation of Earth-like planets. 

Supervised learning methods are routinely used on tabular data of light-curves (either feature based or involving deep learning) to classify the origin of the variations. On the other hand, a not so commonly used approach is to classify the phased curves as "static" images themselves. We are not the first group to propose this approach but since it is still not commonly used I will present the main challenges and achievements we faced from a conceptual point of view. As this is meant to be an informal discussion, some intuitive principles will be explained regarding how our architecture works, how data have to be (and are) processed, etc

ALMA has embarked upon a 150 million Euro upgrade, the so-called “Wideband Sensitivity Upgrade” or WSU, that is currently planned to be commissioned and ready for use around the end of this decade. In this talk I will outline what this upgrade means both in practical terms and for new capabilities. This is a truly massive upgrade, with essentially only the ALMA antennas staying the same. All other parts of the signal chain  - receiver bands, digitizers, data transmission system, over 40 km of optical fibres, correlator – will be replaced or upgraded to give a system with x2 to x4 increase in instantaneous bandwidth. The WSU upgrade will result in a factor of 3-6 increase in continuum mapping speed and a factor of 2-3 increase in spectral line imaging speed. Importantly, ALMA users will no longer need to sacrifice bandwidth in order to work at high velocity resolution (e.g., 0.1 km/s). For ALMA operations, a major change will be that the ALMA correlators, which are currently at >5 km altitude, will be replaced by a correlator at the ALMA Base Camp (Operations Support Facility at 3 km altitude). To meet the challenges of this era of intensive ALMA Development, for ALMA 2030 and beyond, the ESO ALMA Support Centre (EASC) has recently created a new department for Development. In this talk I will describe the new EASC structure and other ways that the EASC is stepping up to the delivery of this - in essence - brand new ALMA.

Gas is the dominant mass constituent of protoplanetary disks and its distribution and evolution have a profound impact on every major step of planet formation: planetesimal formation, accretion of planetary atmospheres, and migration of planets. Yet, we only have a limited understanding of how much gas a typical disk has, how the gas disk evolves and what mechanism(s) drives its global evolution.

In this talk I will show measurements of the gas disk size can be used to indirectly study the mechanisms that drive disk evolution and I will discuss what we learned from current observations.

I will also present some of first results of the ALMA Large Program AGE-PRO, which aims to trace the evolution of the gas throughout the lifetime of protoplanetary disks by quantifying gas masses and gas disk sizes for 30 disks across the whole range of disk lifetimes (0.1-10 Myr).  

Paper: https://arxiv.org/pdf/2307.03222.pdf

Low-mass star-forming regions are blooming in emission from abundant complex organic molecules (carbon-containing molecules of at least 6 atoms). Unbiased spectral surveys and the advent of state-of-the-art interferometers like ALMA have tremendously expanded our understanding of the chemical composition of protostellar regions. The earliest stage of star formation, the prestellar core, is the birthplace of complex organic molecules under interstellar physical conditions. Upon gravitational collapse, a young protostar with a protoplanetary disk is formed. The concurrent heating and UV irradiation boost the production of complex organics. It is thought that the largest reservoir of complex organics is in interstellar ices, which can now be directly probed by the JWST. Meanwhile, thermal desorption in the warm inner regions around protostars allows us to readily observe such species in the gas with ALMA. In the outer parts of a protoplanetary disk, solid complex organics become integrated into forming comets and planets.

Our Solar System was once too an infant low-mass protostar embedded in its natal cloud. The most pristine relics of this time that survive to this day are comets. Recently, cometary science experienced a significant boost as a result of the large wealth of data coming from the ESA Rosetta mission that escorted comet 67P/Churyumov-Gerasimenko for two years. In my talk, I will highlight recent observational investigations of complex organics from cores to protostars, including studies of methanol isotopologs in the prestellar core L1544 and the comprehensive chemical inventory of the low-mass star-forming region IRAS 16293-2422. I will present the chemical trail that connects the earliest phases of star formation with comets in our Solar System. I will address the story told by the comet’s volatile inventory and isotopic ratios about the connections with protostellar and prestellar phases, thereby bring forward the idea that comets of our Solar System reflect to a degree the complex organic composition of the innate core that birthed our Sun.

MPE: Women in Astronomy (scientific talk, in English)

The Assembly, Integration and Verification of a system on an observatory is a critical part of the lifetime of a project. We explain the main steps needed for this activity based on experience gained on La Silla Paranal Observatory. It covers the preparation with the logistics, the safety , the procedures, the Interfaces, the team the AIV itself with the assembly in integration hall, transport to the telescope and integration on to the focus, but also few words about the verification on sky, the commissioning and the validation for operation.

The presentation is based on successful and less successful experiences, which hopefully gives an hint at the complexity of implementing such unique systems on a remote area.

I will present some of my experiences moving from engineering to Astronomy. Some of the advantages and disadvantages of this change and also some differences between the two fields I've seen along the way. It was a good idea? We will see...

The masses of the supermassive black holes in AGNs can be determined by resolving the BH sphere of influence in time via reverberation mapping (RM). The resulting relationship between the broad-line region (BLR) radius and AGN luminosity serves as a baseline for measuring black hole mass (MBH) across the entire Universe.  For an increasing number of nearby AGNs, time-costly high signal-to-noise and high cadence RM data provide insights into BLR geometry and kinematics, offering independent MBH measurements. In combination with spatially-resolved measurements of the host galaxy kinematics, this enables us to constrain the MBH-host galaxy scaling relations with unprecedented resolution. In this talk, I will present the calibration of the MBH-stellar-velocity-dispersion relation for a sample of AGNs with velocity-resolved lags from the BLR. I will discuss the biases introduced by different aperture sizes, host galaxy morphologies, and AGN luminosities, along with the consequences for interpreting such scaling relations as tests for the black hole - host galaxy co-evolution.

I will show observations of ALMA and JWST, along with radiative transfer models to analyse the physical and chemical conditions of protostellar systems which could be where planets start to form. From the observational side, I will use ALMA to quantify complex organic molecules (COMs) in the gas around young protostars, and show that their abundances are consistent with their formation under similar conditions, likely in ices of the prestellar phase. I will then show observations of JWST that (tentatively) detect two nitrogen-bearing COMs in interstellar ices for the first time. From the modeling side, I will use radiative transfer models to investigate how physical conditions such as source structure can change molecular emission and molecular abundances with emphasis on their implication for ALMA and JWST observations. Finally, I will use high angular resolution ALMA observations to further explore the predictions of radiative transfer models with a bonus of a disk wind detection in two new molecules.

Optically active confined spins in solids such as semiconductor quantum dots, colour centres in diamond and atomic-scale defects in 2D-semiconductors are of interest for a wide range of applications in quantum science and technology. In the context of photon-based quantum technologies electron and hole spins localized in single quantum dots can be used for the high rate (~100\,MHz) on-demand generation of single photons with excellent quantum indistinguishability. This talk will provide a snapshot of the recent progress and challenges for quantum light sources, spin-photon interfaces, optical interconnection of distant spins, as well as outlining recent progress in quantum state detection using superconducting nanowires. Finally, we will also explore how spin states in emerging 2D-semiconductors provide fascinating perspectives in quantum sensing and metrology.

We will reminisce about the what happened leading up to the discovery of the accelerated expansion and what it took to get there. Some of the consequences of this discovery will also be presented.

The SPECULOOS (Search for habitable Planets EClipsing ULtra-cOOl Stars) project aims to perform a transit search on the nearest (< 40 pc) ultracool (<3000K) dwarf stars. The project is based on a network of 1m robotic telescopes, composed by the four ones of the SPECULOOS-Southern Observatory (SSO) in Cerro Paranal, Chile, one telescope of the SPECULOOS-Northern Observatory (SNO) in Tenerife, and the SAINTEx telescope in San Pedro Martir, Mexico. The prototype survey of the SPECULOOS project on the 60 cm TRAPPIST telescope (Chile) discovered the TRAPPIST-1 system, composed of seven temperate Earth-sized planets orbiting a nearby (12 pc) Jupiter-sized star. The project's main motivation is to discover potentially habitable planets well-suited for detailed atmospheric characterisation with James Webb Space Telescope (JWST) and the upcoming giant telescopes, like the European Large Telescope (ELT). Beside conducting observations of targets from the SPECULOOS input catalog, a fraction of the available observing time of the SPECULOOS network is used to carry out different science goals, the so-called annex programs. I will present an overview of the project, our observation strategy and the management and operations of our facilities. Finally, I will show the latest results of the survey and the synergy of our programs with the Transiting Exoplanet Survey Satellite (TESS) and JWST.

There are strong indications from physics at both infinitesimal and cosmic distances that our current understanding of the laws of nature is only approximate, and must be replaced by deeper principles. Both in particle physics and in cosmology, novel geometric structure have made an appearance that hint at underlying mathematical structure. Many of these insights are driven by theoretical studies of scattering amplitudes -- the basic building blocks used to predict outcomes of particle scattering. In this talk I will review recent progress in this fascinating field.

In our quest to find other Earths, we’ve uncovered an extraordinarily diverse set of outcomes of the star-planet formation process, far beyond our imagination, and yet we have still barely scratched the surface of what we can learn about this eclectic zoo of other worlds. While exoplanet hunters continue the search for the nearest Earth twins, our last decade of study has pushed to understand the atmospheres of these new planets, and how their climate physics and chemistry respond to the environment created by their parents stars. In this talk, I will demonstrate how new instrumentation, high in resolution, precision, and contrast is pushing our understanding of exoplanet atmospheres to increasing detail. I’ll discuss studies of gas giants as well as the crucial preparation we are doing to find biosignatures on nearby rocky worlds with the Extremely Large Telescopes. Finally, I will demonstrate our recent work on techniques to map out storms in giant exoplanet atmospheres, and end by discussing the next phase of exoplanet observations that aim to reveal the surface interactions of rocky exoplanets.

Orbyts is a multi-award-winning movement that partners scientists with schools to empower school students to undertake world-leading research. We aim to address diversity issues in science and to support short-supply science teachers who have extensive time pressures. We accomplish this through multi-term partnerships that are proven to transform science inclusivity, inspire school students and teachers, and ignite scientists' leadership potential. In this discussion I will explain how the Orbyts programme works on a practical level, and share some of the highlights of our most recent impact report.

Multiple populations distinguishable by their light-element content are well studied in many globular clusters (GCs). Additionally iron spreads have been measured in some of them. In this talk an analytical method to determine the number of core collapse supernovae (CCSNe) that must have contributed to this iron spread is presented. From this the duration of star formation during the initial stage of a GC’s development can be computed. For a sample of 55 GCs with known iron spreads we find that the number of CCSNe required to explain the iron spread varies between a few tens of thousands and a few. In most cases, however, this leads to a SF duration typically around 3.5 Myr.

There is a diverse chemical inventory in protostellar regions that has led to the classification of two extreme types of systems: hot cores, for the hot and dense systems that contain complex organic molecules, and warm carbon chain chemistry sources, for the warm and dense regions near a protostar containing unsaturated carbon chain molecules. Since these definitions were presented there has been a growing field to detect these sources and determine any co-existence between these classes of molecules. There have been few studies surveying these molecules in high mass star forming regions—places of significance as the birthplace of most stars. In this talk, I present spectral surveys in two high-mass star forming regions in Cygnus X—AFGL 2591 and IRAS 20126—with the Green Bank Telescope and the IRAM 30m Telescope. From the observed molecular spectra, I first determine the physical conditions of these regions, producing maps of the gas temperatures, column densities, and velocities. Then, the molecular formation routes corresponding to the abundances observed. These results are an initial step in investigating the specific chemical evolution of carbon chain molecules in star forming regions. The chemical makeup of star forming clouds leads directly into that of stellar systems; observing the chemical complexity of star formation and modeling its environment provides an invaluable link between these systems.

Optically active confined spins in solids such as semiconductor quantum dots, colour centres in diamond and atomic-scale defects in 2D-semiconductors are of interest for a wide range of applications in quantum science and technology. In the context of photon-based quantum technologies electron and hole spins localized in single quantum dots can be used for the high rate (~100\,MHz) on-demand generation of single photons with excellent quantum indistinguishability. This talk will provide a snapshot of the recent progress and challenges for quantum light sources, spin-photon interfaces, optical interconnection of distant spins, as well as outlining recent progress in quantum state detection using superconducting nanowires. Finally, we will also explore how spin states in emerging 2D-semiconductors provide fascinating perspectives in quantum sensing and metrology.

Unlike the Hertzsprung–Russell diagram for stars, there remains no formal classification for exoplanets composed of varying proportions of fluids, rock+metals and ice. Still, as with stars, planetary mass and composition – expressed in geochemical and cosmochemical terms – mold bulk physical characteristics and evolutionary paths. Here, I show how combining geodynamics with astrophysical observations provides insights into rocky exoplanet characteristics such as silicate mantle viscosity and intrinsic heat production vs. age. I test the general predictability of such geochemical models with an example from recent atmospheric retrieval data collected from an ultra-hot Jupiter in the WASP-76 system. I conclude with a geochemical evaluation of spectral data of moderately volatile vs. moderately refractory lithophile elements reported from some polluted white dwarfs and what this means for the ultimate fates of rocky planets around Sun-like stars

Paper: https://arxiv.org/abs/2311.13723

Format: pedagogical lecture (45 mins) and hands-on numerical simulations based on Julia (45 mins)

Open Access (OA) publishing has become a hot topic. Funders, research organisations, and universities are developing OA policies that researchers need to know about and adhere to. The fact that models for OA implementation vary and continue to evolve makes it difficult to stay well informed.

In this Informal Discussion, we will review the situation in OA publishing by looking at positive, but also negative aspects, along with a few issues that should be avoided altogether. We will also look at the OA models of major astronomy journals and evaluate if and how they are suited to establish a collaborative, equitable, sustainable publishing landscape.

Przybylski's star is probably one of the most unique stars of our Galaxy. Its spectrum is overloaded with lines of s-process elements. Quantitative analysis shows that the overabundance of these elements in the Przybylski's star atmosphere is enormous. The reason for this is unknown. I will briefly discuss new ideas that may help to better understand this mysterious star and its chemical anomalies.

How much do different physical processes in the interstellar medium -- in particular dynamics, magnetic field and density structure -- influence the formation of massive stars? I will show observational results covering scales of dynamical cloud-cloud collisions to collapsing star-forming regions. Employing studies from mm wavelengths (SMA, NOEMA, ALMA, 30m) to the mid-infrared (JWST), the characterisation of magnetic field, density structure and accretion processes will be discussed.

In today's dynamic landscape, where efficiency and innovation are pivotal, the Julia programming language (https://julialang.org/) demonstrated to be a revolution in scientific and data computing. This programming language got attention for its exceptional speed, versatility and easy to use. In the same line of Python, Julia is used in fields as diverse as finance, healthcare, engineering in addition to be widely used in particle physics. Oliver Schulz (MPP), developer of BAT.jl (Bayesian Analysis Toolkit), will provide a general introduction, background, and some pros and cons of Julia programming language.

Important note, this discussion will continue with some worked examples in the AI Forum at 14:00 (10/01/2024).

I will discuss recent advances in the understanding of globular star clusters from combining space-based data (Gaia parallaxes and proper motions, HST photometry) with data from large ground-based telescopes like the VLT. I will in particular discuss the initial mass function of globular clusters, the evolution of their black hole population and the possible presence of dark matter in globular clusters.

Paper: https://arxiv.org/pdf/2309.13115.pdf