Seminars and Colloquia at ESO Garching and on the campus

The evolution of galaxies is closely connected to the gas environment in which galaxies reside. Traditionally, this tenuous gas that cycles in and out of galaxies has been studied primarily in absorption using quasar spectroscopy. The deployment of large integral field spectrographs at 8 meter telescopes, and in particular MUSE at VLT, is now transforming our view of the interplay between the ambient gas and galaxies by enabling spectroscopy in emission at very low surface brightness. In this talk, I will present highlights from multiple large programmes that are starting to shed light onto the link between gas and galaxies as a function of cosmic time.

Quasars at z>6 are among the brightest sources in the Universe. The mass of their central black holes grows by 20 times in only 100 Myr via gas accretion. At the same time, their host galaxies form hundreds of solar masses per year. How can these extreme sources sustain such a rapid gas consumption? To answer this question we started the REQUIEM survey: an ongoing MUSE effort aimed to dissect the ecosystem where the first massive galaxies at the dawn of the Universe form and grow.  I will present results from the analysis of the first 31 fields. Complementing our ALMA and XSHOOTER data (probing the ISM and the black holes properties), the REQUIEM survey is providing the first insight view on the connection between the inter- and circum-galactic medium, the quasar host galaxy and the accretion of the central black holes in the most massive galaxies at the dawn of the Universe. I will conclude presenting our current constraints on the evolution of the cool gas surrounding quasars in the first 3 Gyr of the Universe and showing how these fit in the current ``cold'' vs. ``hot'' accretion paradigm of galaxy formation.

Join us for the traditional presentation of this year Nobel Prize laureates.

Protoplanetary disk properties are the focus of an intense observational campaign, but the conditions in the inner part of the disks at early phases remain beyond reach. Here we deduce some properties of the early proto-solar disk, by looking at the elemental composition of non-carbonaceous chondrites and of the Earth. The Al/Si and Mg/Si ratios in non-carbonaceous chondrites are lower than the solar (i.e., CI-chondritic) values, in sharp contrast to the non-CI carbonaceous meteorites and the Earth, which are enriched in refractory elements and have  Mg/Si ratios that are CI-like or larger. We show that the formation of a first generation of planetesimals during the condensation of refractory elements implies the subsequent formation of residual condensates with strongly sub-CI Al/Si and Mg/Si ratios. The mixing of  residual condensates with different amounts of material with CI-like refractory element ratios explains the Al/Si and Mg/Si values of non-carbonaceous chondrites. Instead, the supra-CI Al/Si and Mg/Si ratios of the Earth can be explained by the accretion of ~40$% of the mass of our planet from the first-generation of  refractory-rich planetesimals. To match quantitatively the observed ratios, we find that the first-planetesimals should have accreted when the disk temperature was ~1,330--1,400 K at 1 AU,  depending on pressure and for a solar C/O ratio. We discuss how this model relates to our current understanding of disk evolution, grain dynamics, and planetesimal formation.

Is it clear to you, what we indirectly witness when gazing at some recent observations of protoplanetary disks (PPDs)? How do they fit into our theoretical comprehension of planet formation? And what can the oldest known solids tell us about the history of our own Solar System? Well, the last decades of hunting for exoplanets definitely revealed one thing: planet formation is a quite natural consequence of the formation of most stars. Detecting planets or protoplanetary cores in the early stage of their formation can give us immensely valuable information and constraints, both about the planetary product and about its environment. Here at ESO, I will talk about how embedded planetary cores interact with their surrounding PPD. I will give examples of how these effects can lead to observable signatures for ALMA, and how these signatures can in return be interpreted to deliver important information about the environment of planet formation and the planet's motion therein. Besides investigating the direct "live" observation of distant PPDs, I will show that we can also extract some crucial knowledge about the history of our own Solar System by inspecting pristine leftovers of the oldest known solids under the microscope.

The Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to directly probe the neutrino mass with a sensitivity of 0.2 eV (90% CL). KATRIN persues a model-independent approach, solely based on the kinematics of tritium beta decay. In spring 2019 KATRIN performed its first neutrino mass measurement campaign. With this first data set new limits on the neutrino mass could be established, reaching for the first time the sub-eV regime. In this talk these results and the future scientific program of KATRIN to search for sterile neutrinos will be presented.

Galaxies in compact groups live in an environment where galaxy interactions play an important role, similar to the situation in the early universe. The atomic hydrogen is extremely affected by this environment, whereas the molecular gas is relatively normal in most galaxies.

However, the  properties of the molecular gas are drastically different if one selects those galaxies , based on their mid-infrared colours from the Spitzer and WISE satellites, that are  in transitioning phase from active to quiescent. These so-called “canyon”  or "infrared transition zone" galaxies have a considerably lower molecular-to-stellar mass and star formation efficiency than actively star-forming galaxies in compact groups.

This shows the transition from active to quiescent is driven both by a loss of molecular gas and the fact that the remaining gas has lost its capacity to form stars efficiently.

High-resolution observations with NOEMA and CARMA of a few objects confirm the perturbed nature of the of the molecular gas.

A likely reason for this result is that collisions of the ISM are taking place in the “canyon” galaxies that produce shock and inject turbulent energy into the ISM.  These processes have been observed in several individual objects, as e.g. in the intergalactic medium of the compact group Stephan’s Quintet or in the collisional bridge of the Taffy galaxies. 

Galaxy clusters, the most massive collapsed structures in the Universe residing at the connecting nods of the Cosmic Web, are unique probes for exploring the evolution of baryons, nature of dark matter, and constraining cosmological parameters of the Universe. X-ray observations of clusters of galaxies provide insights into overall structure of the Universe by capturing bulk of the baryons from small spatial scales to the cosmological Large Scale Structure. In this talk, I will review the recent advancements in understanding of the structure and evolution of baryons from cluster cores to outskirts as well understanding the nature of dark matter in these massive reservoirs of dark matter. In addition, I will highlight the significance of ongoing all-sky survey with eROSITA on-board the Spektr-RG X-ray observatory in revolutionizing the cluster astrophysics and cosmology.

ALMACAL is an extensive (sub-)millimetre survey taking advantage of the high sensitivity reached in the fields of ALMA calibrator observations. We analyse all calibration data taken by ALMA since Cycle 1 (more than 2000 hours of observing time!) to conduct a number of surveys, including multi-band and multi-epoch surveys of dusty star-forming galaxies, a blind CO survey to study the evolution of the cold gas content of the Universe, redshifted molecular absorption line surveys, and line intensity mapping. In addition, the data offer a unique opportunity to investigate the spectral behaviour and variability of a large sample of bright extragalactic sources: the calibrators themselves. Here, we give a summary of the ALMACAL survey strategy and the science potential, addressing a large range of problems in extragalactic astronomy.

Despite the tremendous success of the Standard Model in describing the fundamental forces of nature, there is abundant evidence of phenomena outside the reach of this theory, such as the unexplained mass hierarchy within fundamental particles, the existence of dark matter, or the fact that neutrinos, which are assumed to be massless, have instead small but non-zero masses. All of these can be probed by studying tau lepton decays, where unambiguous signs of new physics might manifest in the form of lepton number or lepton flavor violating processes.

The Belle II experiment at SuperKEKB, which has recently completed commissioning in 2018, offers the ideal environment for such studies with its large tau pair production cross section. Belle II started main operation in 2019, with the ultimate goal to record an unprecedented 50 ab−1 of e+e- collision data. I will cover the short and long term prospects of tau measurements at Belle II.

How and when in the star formation sequence do dust grains start to grow into pebbles is a cornerstone question to both star and planet formation. 

I will present how our recent observations from ALMA and NOEMA of the dust continuum emission properties in young protostellar envelopes call for significant grain growth, less than tenth of a million years after the onset of collapse. Confronting our observations against synthetic observations of solar-type protostellar core formation MHD models, we were able to test the dependency of the resulting dust (polarized and unpolarized) emission with various grain size distributions, including grains up to ~50 microns. 

Our work shows that large dust grains are required to (i) produce  polarized dust emission at levels similar to those currently observed in solar-type protostars at millimeter wavelengths (Valdivia et al. 2019), and (ii) explain the variations of dust emissivity observed at scales 100-1000 au in the youngest objects (Galametz et al. 2019). 

I will describe new avenues to explore dust pristine properties and describe better in the future, for example, the initial conditions for the formation of planetesimals.

In this second part, I will connect basic theory of optical interferometry to recent results, especially from GRAVITY on VLTI. The goal is for the audience to understand how astrophysical results are obtained from complex visibilities, not from equations, but from basic principles.

Theoretical arguments suggest that the energy released by the black hole at the center of most galaxies may play an important role in shaping the properties of the interstellar medium (so-called AGN feedback). In particular, AGN-driven, galaxy wide massive outflows may not be a rare and peculiar phenomenon, but a fundamental process affecting the bulk of the baryons in the universe. Hundreds of hours of observations from the ground have been used in the last decade to characterize such outflows and their impact on the host galaxies using e.g. NIR IFU on 8-10m telescopes to trace the ionized gas or the molecular phase with ALMA.  

I will report on the first results of a recently completed Large Programme with SINFONI/VLT (SUPER) on a sample of AGN at z~2. SUPER aims to address the following questions: a) demography of AGN driven outflows on a statistical sample of AGN at cosmic noon; b) how the properties (e.g. energetics and geometry) of such outflows are connected with the properties of the central SMBH; c) which is the impact of such outflows on the gas content of the host galaxy.  

I will finally describe further developments in this research area using facilities that will become available in the future (e.g. JWST, ELTs, SKA, Athena).

Understanding and characterizing the distribution and properties of stars in the Galactic stellar disk and its structure is of fundamental importance to study the evolutionary history of our Galaxy. In this talk, I will discuss the vertical stellar disk structure of MW-like galaxies using the large data provided by the IllustrisTNG50 simulation, the highest-resolution run of the IllustrisTNG suite of cosmological-magnetohydrodynamical simulations. I will present the demographics of TNG50 MW-analogs sample, focusing on the disk flaring: how and by how much the vertical disk scale height increases at larger galactocentric distances. The unique set of a hundred of MW-like galaxies provided by TNG50, allows us to investigate how unique and special our Galaxy is: are the known observational features in place in all TNG50 MW-analogs? How often the disk flaring occurs in our MW-like sample? Across all MW-mass disk galaxies, do young and old stellar populations display the same amount of flaring? Moreover, I will discuss whether the degree of flaring depends or correlates with other structural properties, such as disk heights, disk lengths and the gas fraction.

To form giant planets in protoplanetary disk lifetime, small micron sized particles must grow rapidly to larger grains. To do so, they need to settle efficiently towards the disk midplane, and likely concentrate into dust traps. Currently observational constraints on vertical settling, which is intrinsically related to grain growth, are incomplete. During this talk, I aim to add constraints on vertical settling efficiency. I will compare optical/infrared scattered light with millimeter observations of several inclined disks, to probe the difference in vertical extent between micron-sized and larger millimeter-sized dust grains. Disks observed at large inclination are of particular interest as they provide a unique point of view to determine their vertical extent. I will show that the most edge-on disks of our sample, well resolved vertically, are compatible with having a millimeter dust scale height of about 1au at 100 au. Compared to a gas scale height estimated to about 10 au at 100 au, this result indicates very efficient vertical settling. This increasing dust density in the midplane likely enhance the efficiency of planet formation.

Bring your Fourier transform and come see why telescopes and interferometers behave exactly the same.

We study the properties of the Sydney University Molonglo Sky Survey (SUMSS) 843 MHz radio AGN population in galaxy clusters from two large catalogs created using the Dark Energy Survey (DES). The first contains ⇠11,800 optically selected redMaPPer clusters (RM-Y3; M200c > 1014M, z < 0.8) and the second contains ⇠1,000 X-ray selected clusters from the ROSAT All Sky Survey (MARD-Y3; M200c > 2 ⇥ 1014M, z < 1). These samples allow us to push to higher redshift than in previous studies. We show that cluster radio loud active galactic nuclei (AGN) are highly concentrated around cluster centers to z ⇠ 1. We measure the halo occupation number for cluster radio AGN above a threshold luminosity, finding that the number of radio AGN per cluster increases with cluster halo mass as N ~M1.2±0.1 (N ~ M0.68±0.34) for the RM-Y3 (MARD-Y3) sample. Together, these results indicate that radio mode feedback is favoured in more massive galaxy clusters. Using optical counterparts for these sources, we demonstrate weak redshift evolution in the host broad band colors and the radio luminosity at fixed host galaxy stellar mass. We use the redshift evolution in radio luminosity to break the degeneracy between density and luminosity evolution scenarios in the redshift trend of the radio AGN luminosity function (LF). The LF exhibits a redshift trend of the form (1 + z)^g in density and luminosity of g_d = 3.0 ± 0.4 and g_l= 0.21 ± 0.15, respectively, in the RM-Y3 sample, and g_d= 2.6 ± 0.7 and g_l= 0.31 ± 0.15, respectively, in the MARD-Y3 sample. We discuss the implications for physical drivers of radio mode feedback in cluster AGN, suggesting confining pressure of the ICM and mergers of infalling, gas rich galaxies within central giant ellipticals as possible mechanisms influencing the measured mass and redshift trends. We use the cluster radio galaxy LF to estimate the average radio-mode feedback energy as a function of cluster mass and redshift and compare it to the core (< 0.1R500) X-ray radiative losses for clusters at z < 1. We find the imbalance of radio mode feedback and X-ray radiative losses is qualitatively consistent with that required to explain the observed cool core population and the trend of increasing ICM mass fraction with mass observed over the same redshift range.

Have you ever wondered how major companies including Apple, Google, Airbnb, Nike or SAP come up with the ideas for their products? These companies use flavours of the user-centric design method called Design Thinking. This method is a step-by-step approach to innovation unleashing the creative potential of a group of people. It can be used to design products or systems or for trying to find solutions to any complex problem in life. In this informal discussion we look the background, the ingredients and the steps of Design Thinking and we can discuss together whether or not the approach could be used within ESO. 

We have used SCUBA-2 and ALMA to detect 75 sources in 100 square arcminutes of the Chandra Deep Field-South, by far the highest density sample of faint 850 micron sources yet obtained.  The observed region matches the deepest portion of the 7 Ms Chandra image, making it possible to probe low-luminosity AGN at very high redshifts.  We find that most of the ALMA sources appear to be consistent with having both their X-ray and submm emission driven by star formation.  Indeed, only 20% of the ALMA sources have intermediate X-ray luminosities (rest-frame 8–28 keV luminosities of 10^42.5-10^44 erg s^-1), and none has a high X-ray luminosity (>10^44 erg s^−1).  Conversely, we find extreme star formation rates (>300 solar masses per year) in some intermediate X-ray luminosity sources, but not in any high X-ray luminosity sources.  I will discuss how our results seem to be consistent with gas clearing from the galaxies.

The journey that Astronomers have taken in order to recover a clear picture of the heavens has been a long one. Earth's turbulent atmosphere sets a limit on the scales of detail that can be recovered - an impediment once believed so fundamental it would set a boundary to what humanity could know. Progress in astrophysics throughout the 20th century was largely made in spite of the fact that we mostly failed to solve this problem, rather than because we did. Recovering structures at the highest angular resolutions obtainable at the formal diffraction limit of a modern large ground-based telescope continues to present interesting challenges. With the past as our guide, I discuss new ways to formulate the image formation process.

When, in theoretical physics, we attempt to derive the quantum properties of a black hole, several difficulties are found on our way. In this talk it is shown how these difficulties can be overcome, but not without reformulating some of the laws of nature. This is very important to know, because this way one might uncover new features of the gravitational force when subject to the laws of quantum mechanics.

We claim that the evolution operator for the quantum black hole during short time intervals can be deduced unambiguously from standard quantum field theory in curved space-time, merely by demanding unitarity and completeness for pure quantum states. We explain its Hilbert space and the topologically non-trivial space-time that emerges in our approach. Since there are no run-away solutions, the behaviour at arbitrarily long time scales follows unambiguously. Curiously, string theory does not seem to work flawlessly when details at the Planck scale are addressed.

Exoplanet population studies indicate that small rocky planets should be common around very low-mass stars and brown dwarfs (‘ultra-cool dwarfs’, SpT>M7). However, the M8 star TRAPPIST-1 is currently the only ultra-cool dwarf known to harbour planets. I will describe and present preliminary results from our on-going Spitzer search for transiting planets around equator-on ultra-cool dwarfs.

Accreting supermassive black holes are thought to drive the energy output in the form of radiation and relativistic plasma outflows (jets) seen in Active Galaxies. As such they allow us an excellent opportunity to probe the realm of extreme physics.

Hosting one of the most massive black hole in the local Universe, the nearby radio galaxy M87 has become a prominent target in this regard with recent campaigns enabling to study astrophysical processes such as jet formation or the production of non-thermal radiation in unprecedented detail.

I will highlight recent results on the high-energy diagnostics of M87, ranging from non-thermal magnetospheric processes in the vicinity of its supermassive black hole to the X-ray characteristics of its large-scale jet.

On black hole horizon scales, gap-type particle acceleration, accompanied by curvature and Inverse Compton radiation, could be responsible for the rapidly variable gamma-ray emission seen by current ground-based VHE instruments, introducing a link between gamma-ray production and jet formation. On larger scales, complex X-ray emission features have been emerging which can be used to distinguish physical scenarios for the origin of the extended X-ray emission in the kilo-parsec-scale jets of AGN. 

The cosmic ray ionization rate ζ is an important and uncertain parameter in both chemical and dynamical models of prestellar cores.  It seems unavoidable that ζ must decrease as the column density increases, but the magnitude of this drop is highly uncertain.  I will discuss the physics of a few different transport models and the conditions under which each model is appropriate, highlighting the predictions for the attenuation of ζ with increased column density.  I will then discuss some of the observational constraints on ζ, and some ongoing work on my part to jointly constrain ζ and the degree of dust evolution in dense cores based on the measured gas temperature.

One of the most exciting opportunities offered by the new VLT beam combiner GRAVITY is to directly resolve the immediate regions around the super-massive black holes (SMBHs) in the center of active galaxies (AGN), i.e. the Broad Line Region (BLR) and the hot dust ("torus") structures. We are exploiting this capability to study the inner workings of AGN in the K-band on unprecedented micro-arcsecond (sub-pc) spatial scales. This has led to the first interferometric detection of a BLR (finding ordered rotation and measuring the black hole mass in the quasar 3C273), as well as to the first 0.2 parsec resolution K-band image of the dust sublimation region in the nucleus of the Seyfert 2 galaxy NGC1068 (finding a ring-like structure which is inconsistent with the expected signatures of a geometrically and optically thick torus). I will summarize these and other recent results , discuss their scientific (and historical) context, and give and outlook how such observations (along with already planned or potential future upgrades of GRAVITY) might contribute to the study of the structures and physical processes around SMBHs or to the study of how SMBHs build up their mass across cosmic time.

LP 40-365 is a runaway star, whose atmosphere is dominated by oxygen, neon, and magnesium. Additionally, it contains super-solar traces of iron-peak elements. Its composition and remarkable kinematics suggest this star formed via the failed disruption of a near-Chandrasekhar mass white dwarf in a peculiar thermonuclear supernova that unbound the binary progenitor. LP 40-365 is the prototype of a new class of objects, which appear as low-mass (0.2-0.3 Msun), inflated white dwarfs of 0.2-0.6 solar radii. The known members of this class have a homogeneous chemical composition, physical and kinematic properties. Future theoretical and observational work will help to better constrain the characteristics of their binary progenitors, explosion mechanisms, and nucleosynthetic yields.

The study of dark matter captured inside stars has proved to be a viable indirect search strategy complementary to other direct searches. In this context, only a fraction of the rich diversity of physics found in different types of stars has been explored, with most studies mainly focused in the Sun. In this work we looked to the center of the galaxy and studied the imprint of dark matter particles in two completely different types of stars: low mass main-sequence stars and Red Clump (helium burning) stars. We found that the scattering interactions between baryons and dark matter particles within the central region of these stars can result in effects such as the slowdown of the nuclear burning rate or the suppression of core convection, both of which can have an important impact on the evolution and asteroseismology of the star.

The lower edge of the radio window (10-200 MHz) has been scarcely explored due to the complexity of such observations. In this talk I will review the recent progresses in the observation of the metre-wavelength sky, focusing on the last results obtained with the Low Frequency Array (LOFAR). Then, I will summarize the recent scientific outcomes obtained with LOFAR observations. From the search for radio emission from exoplanets, to the AGN life-cycle, to the study of diffuse radio emission in galaxy clusters. I will conclude presenting the first data release of the LOFAR 2m sky survey at 150 MHz and an sneak preview of the upcoming LOFAR LBA Sky Survey at 50 MHz.

We investigate the stellar kinematics of galactic bulge and disk components using 830 galaxies with various morphological types from the Sydney-AAO Multi-object Integral-field spectroscopy (SAMI) Galaxy Survey. The rotation velocity and velocity dispersion of bulge and disk components have been simultaneously estimated using the penalized pixel fitting (pPXF) method with photometrically defined weights of two components. We introduce a new subroutine of pPXF to avoid physically meaningless solutions. We present the Tully-Fisher and Faber-Jackson relations showing that the stellar mass scales the velocity and velocity dispersion of both bulge and disk components for all galaxy types. Also, we first introduce a tight correlation between the stellar mass and the velocity dispersion in disk components. We show that bulge and disk components are kinematically distinct: (1) two components show scaling relations with similar slopes, but with different intercepts; (2) the spin parameter Lambda_R indicates bulges are pressure-dominated system, and disks are supported by rotation; (3) bulge and disk components present low and high values in intrinsic ellipticity. We reproduce the rotation and dispersion of galaxies using the kinematics and weights of two components. The agreement between the reproduced and observed kinematics suggests the combination of two distinct components draw the kinematics of galaxies.

Star-forming galaxies are known to follow broad correlations between their star-formation rate, stellar mass and metallicity.  Yet, many questions remain about the physics behind these relations.  In this talk, I will highlight some recent results on star-forming galaxies at low mass and high mass from two deep spectral surveys in the Hubble Ultra Deep Field (HUDF).  At low masses, we have used the MUSE HUDF Survey to measure the slope and intrinsic scatter in the galaxy main sequence down to unprecedented low masses.  We find an increased scatter and shallower slope than predicted on the basis of theoretical models.  At the high mass end, we are using the ALMA Spectroscopic Survey in the HUDF to measure the molecular gas content in galaxies without any preselection.  We detect a variety of galaxies in molecular gas, that lie on, above and even below the galaxy main sequence, and examine the local conditions in their ISM using CO, [CI] and dust continuum.  I will argue that now is a good time to push MUSE and ALMA as key instruments to forward our understanding of the physics behind the galaxy main sequence at high redshift, both at low and high mass.

Phosphorus is a crucial element for the development of life as we know it, but because of its low cosmic abundance, until recently its interstellar chemistry was almost totally unknown. Since 2016, the star formation group at Arcetri has made a fundamental contribution to our understanding of the astrochemical processes that involve this element in the star-forming regions of the Galaxy, paving the way for a growing number of studies on this pre-biotic element that had been “forgotten” up to now. Among the most important results, we have achieved the first detection of the PO molecule, the basic bond of phosphates, in two star-forming regions, W51 and W3(OH). Another crucial result was the tight relation between PN - the P-bearing molecule detected first in the interstellar medium and with the highest number of detections in star-forming regions so far - and SiO, a well-known shock tracer. Based on an unprecedented statistic, we have demonstrated that the abundances of SiO and PN, X[SiO] and X[PN], are strongly correlated in a variety of interstellar environments, indicating a similar production process.

Low mass stars, stars within the mass range ~0.5-2 Msun, undergo core helium flash at the end of their first red giant branch (RGB) evolutionary phase. The subsequent abrupt change in luminosity leaves a sharp upper luminosity of the RGB, the Tip fo the Red Giant Branch (TRGB) easily identifiable in a Colour-Magnitude Diagram. A well-defined luminosity of the TRGB has been recognised by Baade and Sandage, and established as a useful distance indicator by Da Costa & Armandroff 1990 and Lee et al. 1993. It has been shown to be competitive distance indicator in comparison with Cepheids, surface brightness fluctuations and the planetary nebulae luminosity function.

After a brief theoretical background for the TRGB method, I will give an overview of methods that have been used to identify and measure the brightness of the TRGB and to calibrate its brightness. I will explain why TRGB is typically applied to I-band filter photometric observations and discuss its calibration in other photometric bands. Applications to measuring distances to (nearby) galaxies and for Hubble Constant H0 measurements will be also presented.

The outskirts of clusters make the best, and most efficient locations to observe and trace the mass assembly processes of the Cosmic Web. Residing at the vertices of this Cosmic Web (Bond et al. 1996), galaxy clusters grow by steady accretion of matter from the surroundings, as well as by discrete mergers with nearby groups and clusters. Supported by simulations, this scenario regarding the total mass content and distribution in filaments themselves remains largely untested. Filaments are vital elements of the cosmic census, containing up to half the baryonic mass of the Universe as a ‘warm hot intergalactic medium’ but also the majority of the dark matter.

Recently, some of the most massive and disturbed clusters have been the centre of attention thanks to the Hubble Frontier Fields (HFF) initiative, which constitutes the largest commitment ever of Hubble Space Telescope (HST) time to the exploration of the distant Universe via gravitational lensing by massive galaxy clusters. These clusters were chosen for their strong lens properties, and are all highly disturbed objects, showing major and minor merging on-going processes, making them ideal target to trace the Cosmic Web assembly.

While combining strong- and weak-lensing regimes to map the total mass with X-rays observations of the hot gas and spectroscopy of cluster galaxies to look at their direction of motion, we can thus study the dynamical scenarios in place within these massive galaxy clusters, and trace the substructures engaged in these processes. I will present the last results we obtained on the HFF clusters, and discuss the different caveats present on both the observing and simulation sides. I will then present the BUFFALO HST large programme, the ’spatial extension’ of the HFF, that started back in July 2018 and should end in June 2020.

One of the most important quantities needed to explain how planets form is the mass of their precursors, protoplanetary disks. Determining the total disk mass – which is dominated by the gaseous component – has proven to be very difficult. On one hand dust-based disk masses depend on the assumptions on the dust properties and on the gas/dust ratio, and on the other hand CO-based gas masses are affected by the uncertainty on the chemical processes. Other molecules, such has small hydrocarbons, can be used to put some constraints on the chemistry. Hydrogen deuteride (HD), on the other hand, is a promising alternative and has already proved to be a game changer thanks to the few detections by the Herschel Space Telescope. SPICA is now the only near-future instrument which may allow us to expand the sample of HD detections and mass measurement in a statistically relevant sample of disks. After summarizing the results from different ALMA disk surveys and their implications, I will present alternative observational strategies which may help us to solve the disk mass puzzle.

From a theoretical point-of-view, magnetic fields are crucial to the evolution of planet-forming disks. However, profound observational constraints are pending. Presently, the number of cutting-edge polarization observations presenting inconclusive data increases continuously. In very recent years, polarization at mm-wavelengths, the classical tracer of magnetic fields, emerged as highly ambiguous, and the pressing demand for comprehensive tools to analyze these new observations is growing. I will present an overview on the sources of continuum polarization with focus on the impact of grain alignment, scattering, and grain porosity on the polarization measurement – as well as a potential solution to this dusty ambiguousness, linearly polarized gas emission.

Efficient scheduling of astronomical surveys is a challenge with an increasing complexity as the observation strategies are becoming  more sophisticated and operational costs are higher. Astronomical surveys require a huge number of observations, implying the need to use efficient schedulers to fulfill and optimize specific constraints. STARS (Scheduling Telescopes as Autonomous Robotic Systems) provides optimal schedulers for diverse infrastructures, and has been successfully applied in several ground and space-based observatories. Currently, STARS is extended to cover multi-observatory coordinated scheduling, a challenging and complex optimization problem that will allow an optimal operation of large astrophysical infrastructures to promote multi-messenger science.

Type Ia supernovae have long been used as probes of the expansion history of the universe. Their standardisable luminosities make them very attractive as distance measures, and they remain indispensable in constraining the properties of dark energy. In this talk, I will give an update from the Dark Energy Survey (DES), including the latest cosmological results using type Ia supernovae to measure the dark energy equation-of-state. I'll also show how large imaging surveys, such as DES, are developing our knowledge of the 'zoo' of cosmic explosions, beyond the classical supernova types. I'll focus on two new classes of explosion: superluminous supernovae, ultra-bright explosions now confirmed out to a redshift of two, and which bring the possibility of measuring distances at higher redshifts than type Ia supernovae; and 'calcium-rich transients', faint-and-fast events that play a critical role in chemical enrichment, and have a surprisingly high intrinsic rate. Finally, I will look forward to what the next decade of LSST and massive spectroscopic follow-up may bring.

This year the Nobel Prize in Physics was awarded and shared between James Peebles "for theoretical discoveries in physical cosmology”, and Michel Mayor and Didier Queloz "for the discovery of an exoplanet orbiting a solar-type star.” During this informal discussion we will give a general overview of the state of the respective research fields at the time these Nobel laureates performed their work. Then we will highlight some of the technical and observational challenges that had to be overcome, and point out how and where they have contributed and transformed their fields (and our view of the Universe).

Though computational methods are widely used in many disciplines, those who author these methods have not always received credit for their work. This presentation will cover recent changes in astronomy, and indeed, in many other disciplines, that include new journals, improved software policies for existing journals, community resources, changes to infrastructure, and availability of new workflows that make recognizing the contributions of software authors easier. This talk will include steps code authors can take to increase the probability of having their software cited correctly and steps researchers can take to improve their articles by including citations for the computational methods that enabled their research.

Soft Collinear Effective Theory (SCET) formalism has been successfully applied to many important observables in collider physics, improving the accuracy of fixed-order predictions via the leading power resummation of large logarithmic contributions which appear in certain regions of phase space. Recently, a renewed interest in subleading power corrections has arisen in the theoretical community.  In this talk, I will discuss the framework for the threshold resummation of the Drell-Yan process at next-to-leading power using SCET. I will explain how to derive the general factorisation formula and discuss the new objects that emerge beyond leading power: collinear jet functions and generalized soft functions. The leading logarithmic solution of the RG equations will be  presented, and I will perform a comparison with known fixed order results.

Chondrules are silicate spheroids found in meteorites, and they serve as important fossil records of the early solar system. In order to form chondrules, chondrule precursors must be heated to temperatures much higher than the typical conditions in the current asteroid belt. We present a new scenario in which planetesimals in the asteroid belt region are excited to high eccentricities by the Jovian sweeping secular resonance in a depleting disk, leading to efficient formation of chondrules when they pass through the bow shocks of planetesimals. We find that 50─2000 km planetesimals can obtain eccentricities larger than 0.6 and cause effective chondrule heating. Our model implies that the disk depletion timescale is t_dep ≈ 1 Myr, comparable to the age spread of chondrules, and that Jupiter formed before chondrules, no more than 0.7 Myr after the formation of calcium aluminum inclusions.

Experimental physics relies by definition on hardware to carry experiments, with a growing tendency towards large and complex infrastructures (LHC, ELT, JWST…). Developing and building such infrastructures is alone an engineering challenge that pushes the boundaries of human knowledge. Mechanisms, metal structures, materials and heat transfer - including cryogenics - are some of the technical aspects covered by Mechanical Engineering. This talk introduces this engineering branch, skipping through its main concepts and tools. Examples referring to the ELT and other facilities are also provided.

The direct detection of gravitational waves from merging black holes by LIGO in 2015 has revitalized the area of gravitational wave astrophysics. The origin of black hole and neutron star mergers is still unclear, however, and various scenarios have been proposed. In this talk, I focus on the evolution of multiple-star systems such as triples, quadruples, and binary systems in galactic nuclei. I discuss the complex interplay between dynamical, stellar, and binary processes in these systems. Finally, I highlight future directions for modeling their long-term evolution, in order to make predictions for future gravitational wave observations.

A prominent jet-driven outflow of CO(2-1) molecular gas is found along the kinematic minor axis of the Seyfert 2 galaxy ESO 420-G13, at a distance of 340-600 pc from the nucleus. The wind morphology resembles a characteristic funnel shape, formed by a highly collimated filamentary emission at the base, likely tracing the jet propagation through a tenuous medium, until a bifurcation point at 440 pc where the jet hits a dense molecular core and shatters, dispersing the molecular gas into several clumps and filaments within the expansion cone. We also trace the jet in ionised gas within the inner ~340 pc using the [NeII]12.8µm line emission, where the molecular gas follows a circular rotation pattern. The wind outflow carries a mass of ~8 x 10^6 Msun at an average wind projected speed of ~160 km/s, which implies a mass outflow rate of ~14 Msun/yr. Based on the structure of the outflow and the budget of energy and momentum, we discard radiation pressure from the active nucleus, star formation, and supernovae as possible launching mechanisms. ESO 420-G13 is the second case after NGC 1377 where the presence of a previously unknown jet is revealed due to its interaction with the interstellar medium, suggesting that unknown jets in feeble radio nuclei might be more common than expected. Two possible jet-cloud configurations are discussed to explain the presence of an outflow at such distance from the AGN. The outflowing gas will likely not escape, thus a delay in the star formation rather than quenching is expected from this interaction, while the feedback effect would be confined within the central few hundred parsecs of the galaxy.

I present ALCOHOLS, a 2.7 square degree survey in the CO(3-2) line covering a substantial area in the Orion giant molecular clouds A and B. The survey was done using the SuperCAM 64-element receiver array at APEX. I I will present first results, including a first analysis of a sample of more than 70 protostellar molecular outflows that have been extracted from the survey data.

The Fornax cluster provides a uniquely compact laboratory in which to  study the detailed history of early-type galaxies and the role played by the environment in driving their evolution and their transformation from late-type galaxies. I would like to present a new "picture" of the Fornax cluster that emerged like a puzzle in the latest years. It is based on dedicated studies using deep imaging from the Fornax Deep Survey (FDS),  and the high-quality integral-field data obtained with MUSE@VLT from the Fornax3D project. Both surveys map the Fornax cluster out to its virial radius. The analysis pointed out the complex structure of the cluster, suggesting that it is not completely relaxed inside the virial radius. The bulk of the gravitational interactions between galaxies happens in the W-NW core region of the cluster, where most of the bright early-type galaxies are located and where the intra-cluster baryons (diffuse light and globular clusters) are found. We suggest that the W-NW sub-clump of galaxies results from an infalling group onto the cluster, which has modified the structure of the galaxy outskirts (making asymmetric stellar halos) and has produced the intra-cluster baryons (ICL and GCs), concentrated in this region of the cluster. These studies could be considered as a benchmark for (simulations of) the assembly and evolution of galaxies in a cluster environment.

Interferometric observations of the dust distribution in protoplanetary disks pose the degenerate problem of recovering the brightness of an on-sky source from sparsely sampled Fourier data. The most common approach to this problem performs image reconstruction with CLEAN deconvolution prior to scientific analysis. Yet this practice places both fundamental and practical limits on the reconstruction accuracy. In this talk I will present our open source code to fit the interferometric visibilities directly in their native, Fourier domain in an accurate (super-CLEAN resolution), nonparametric and fast (<1 minute) way with a Gaussian process. The technique is currently performed in 1D, where the seemingly ubiquitous gap and ring structures in axisymmetric discs can be well characterized. I will then motivate how our fits are recovering disc structures beyond the CLEAN imaging resolution both through theory and demonstration with synthetic and real low and high resolution mm observations. Discussing scientific applications of our model, I will conclude by briefly noting planned extensions of the code.

The study of stellar magnetic fields — particularly for main sequence stars — has advanced enormously in the last couple of decades thanks to the increased availability of high resolution echelle spectrographs and spectropolarimeters. I’ll take you on a very brief tour of our current understanding of stellar magnetic fields, starting with the main techniques that are used to detect them across a range of spectral types. I’ll then outline what these techniques have revealed and how these are affecting our understanding of stellar and planetary formation and evolution.

The first image of the shadow of a supermassive black hole located in the core of the galaxy Messier 87 was recently released by the Event Horizon Telescope (EHT) Collaboration. This image is a high point following decades of VLBI (Very Long Baseline Interferometry) observations of Active Galactic Nuclei (AGN) and relativistic jet structures. VLBI at mm wavelengths enables the study of the conditions and interactions close to supermassive black holes on a range of scales. I will give an overview of this research in the context of astrophysical studies of AGN. Finally, I will give an outlook to the future of this research at Event Horizon scales.

Being a scientist, especially in astronomy, should be a joyful experience. Yet we can sometimes find ourselves overwhelmed with the pressure, stress and uncertainty the can come with the job. Furthermore we can encounter people and situations that may make you feel miserable and question is it all worth it. We will explore why we can lose the joy of science and discuss what we can do as a group and - importantly for ourselves - to try and navigate the challenges of the career whilst maintaining the joy and enthusiasm that it should entail.

Short of sending spacecraft to an asteroid, the highest-resolution way to learn about asteroids is to study them with radar.  Arecibo Observatory in Puerto Rico is home to the world's largest single-dish radio telescope and the most powerful planetary radar system for asteroid studies.  The 305-meter diameter facility dedicates hundreds of hours a year to improving our knowledge of near-Earth asteroids and comets with planetary radar.  Radar observations reveal a wide variety of asteroids shapes, surface features, and sizes, as well as asteroid moons.  Important not only for robotic solar system exploration of asteroids, radar-derived asteroid shape models help us plan for potential asteroid hazard mitigation and future human exploration of asteroids.  I will show recent results from the Arecibo planetary radar system and discuss the upcoming asteroid sample return mission OSIRIS-REx that launched in September 2016 to return pieces of a 4.6-Gyr old asteroid to Earth.

The estimated number of black holes in the Galaxy from simple stellar evolution considerations is about 100 million, a large fraction of which are expected to besingle. Yet, not a single isolated black hole has been detected to date -- all the few dozen black hole mass determinations so far have been in binaries. In addition, there is a nagging inconsistency between the measured masses of black holes in our Galaxy, masses expected from theoretical calculations, and the LIGO measurements. Mass determinations of a few isolated, stellar-mass black holes will provide important clues in our understanding of black holes. Astrometric microlensing is the only available technique capable of detecting isolated black holes and measuring their masses. I will discuss the technique, and our HST programs aimed at the first detections of stellar-mass black holes through this technique.

Gap-opening planets can generate dust-trapping vortices that may be responsible for some recently-discovered crescent-shaped dust asymmetries in transition discs. Although this model can explain some of these features well, most previous numerical studies of vortices have neglected the time it takes to grow a planet to Jupiter-size, a process that may last more than 1000 orbits. In our work, we incorporate more realistic planet formation timescales into two-fluid (gas and dust) hydrodynamical simulations, which we use to generate synthetic ALMA images of planet-induced vortices. With longer planet formation timescales, we show that planets trigger shorter-lived vortices with much more elongated shapes, if they even form at all. Although these elongated vortices still trap dust, that dust is no longer trapped at the center of the vortex. Instead, with a flatter pressure bump and disruptions from the planet’s overlapping spiral density waves, the dust instead circulates around the vortex. This motion spreads the dust out over a wider azimuthal extent (> 180 degrees) and carries the peak off-center (often by > 30 degrees with sufficient resolution). We compare our synthetic images to those from recent disk surveys, and identify candidate elongated vortices. Overall, our work demonstrates that observing elongated planet-induced vortices would help constrain the timescales for planet formation.

ALMA has now surveyed the protoplanetary disc population in many nearby star-forming regions. I will talk about statistical inferences from these surveys that suggest we are not seeing the bulk of the material that forms planets. An underlying planetesimal mass reservoir, stirred by oligarchic growth at a few Myr, may explain the evolution of the millimeter luminosity distribution.

In the first half of the talk we will go over a brief introduction to deep learning together covering the history, differences with machine learning and its recent advances. Then we will review the general use cases, starting with typical ones like classification, regression and finishing with auto-encoders.

In the second half, we will detail two exemplar data-driven applications in astronomy: a) TransiNet: real-time transient detection using ConvNets, b) "Letting spectra speak for themselves!

Thanks to ALMA our understanding of gas and dust in galaxies over cosmic time and their connection to other galaxy properties has improved dramatically. I will discuss a number of the results from the ALMA large program ASPECS, a spectroscopic survey at 1 and 3 millimeter with ALMA of the Hubble Ultra Deep Field. This survey marks the deepest observations of a 4.2 arcmin^2 contiguous area on the sky and pushes our understanding of gas and dust in high-redshift galaxies even further. The aims of this survey include measuring the cosmic evolution of the molecular gas density and the gas properties of galaxies; the deepest measurement of the 1 millimeter continuum number counts and it’s connection to the underlying galaxy population; improving our understanding of dust obscuration at high redshift; and constraining the [CII] luminosity (function) of high-redshift galaxies. I will present the main survey design and after that focus on some of the individual results of the survey, guided by the interest of the audience.

It is well known that old stellar populations are dominated by evolved short-lived hot stars (Teff  > 10, 000 K). Such stars emit most of the light in the Ultra-Violet (UV) and have similar optical colours over a wide range of temperatures because the optical passbands are far enough down the Rayleigh-Jeans tail of their spectral-energy distributions. They are therefore inconspicuous in optical images of old star clusters in comparison to the large numbers of main-sequence stars and red giants. But, far-ultraviolet (FUV) and near-ultraviolet (NUV) imaging of old stellar populations provide a unique opportunity for the studies of white dwarfs, blue stragglers stars (BSSs), post asymptotic giant branch star and compact binaries etc. Since they are easily discerned in the rarefied topography of Far UV/Near UV colour magnitude diagrams. Consequently, a number of space missions including Hubble Space Telescope have imaged a number of globular and a few old open star clusters since they are not only ideal objects but also span a broad range of stellar populations in both age and chemistry, as well as a variety of environments.

In light of the above, a key science project on this topic has been identified by the ASTROSAT, India’s first multi-wavelength (X-ray to optical) space-born astronomy mission launched successfully on 28 September 2015.  Life time of the mission is 5 years. Five scientific payloads are mounted on the ASTROSAT. One of them is UV Imaging Telescope (UVIT).  It has spatial resolution of ~1.2 arc-sec, large field of view (~ 28 arc-min diameter) and also has number of filters in both FUV and NUV regions.  UVIT observations, therefore, provide very useful observations for extracting the properties of UV bright stellar populations in a star cluster. A few results published recently will be highlighted in this talk along with future Indian Space mission in UV as well as encouraging capabilities of recently installed Indo-Belgian 3.6 meter optical telescope located in central Himalayan region of India.

P/2016 G1 is an "active asteroid", i.e. a main belt asteroid that suddenly displayed a cloud of dust. We observed its evolution for a few month, and could re-constitute the details of what happened to it using a few millions of test particles, a little detective work, and hydrodynamics simulations of nuclear weapon explosions.

The cosmic baryon cycle is key to our understanding of galaxy formation and evolution. Open questions are: How do baryons cycle into and out of galaxies? What physical processes drive the dramatic change in the cosmic star formation rate history? What galaxies harbor half of the star formation activity in the universe enshrouded in dust? I show how we transform ALMA into a survey telescope acquiring more than 2000h of observing time. I present measurements of the molecular gas across cosmic time offering new clues on the evolution of the star formation rate history. Furthermore, I highlight new results from our search for the dusty star-forming galaxies.

Supernovae (SNe) and Long-duration Gamma-ray Bursts (GRBs) are exploding stars and constitute the most powerful explosions in the universe. Since they are visible over large cosmological distances, release elements heavier than Helium, and leave behind extreme remnants such as black holes, they are fascinating objects, as well as crucial tools for many areas of astrophysics, including cosmology. However, for many years the fundamental question of which stellar systems give rise to which kinds of explosions has remained outstanding, for both Type Ia SNe used for cosmology as well as for Superluminous SNe and long-duration GRBs that must originate from special kinds of massive stars. I will discuss the exciting recent progress that we have made on this question in key areas by publishing and thoroughly analyzing the largest data sets in the world at the time. I will conclude with an outlook on how the most promising venues of research - using the existing and upcoming innovative large time-domain surveys such as ZTF and LSST - will shed new light on the diverse deaths of stars.

I will provide for those that couldn’t attend a succinct and very biased account on the ESO workshop on Artificial Intelligence in Astronomy that took place July 22-26 and attracted more than 130 participants.

As the two most abundant molecules in protoplanetary disks around young stars, H2 and CO are critical tracers of the planet formation environment. We have used the Cosmic Origins Spectrograph onboard the Hubble Space Telescope (HST-COS) to observe emission from electronic transitions of both molecules at ultraviolet wavelengths. The UV spectral features were fit with a 2-D radiative transfer model to reproduce the radial distributions of gas in the inner disks around a sample of T Tauri stars. By combining kinematic information from UV-H2 and UV-CO for the first time, we provide a more complete census of molecular structure in the planet forming regions of our sample of young disks. In addition, the UV radiation field is critical in regulating photochemical reactions within the disk. We have used the HST-COS spectra to reproduce the LyA profile and FUV continuum reaching the gas. We compare our results to emission from CN (observed with ALMA) and HCN (observed with Spitzer-IRS), which are chemically dependent on UV photons.

Observations in the infrared and sub-mm using the Herschel and ALMA suggest that stars form in high mass density filaments in giant molecular clouds while embedded star clusters and high mass stars reside at the intersection of filaments, hubs and ridges. What imprint does the star formation in filaments leave in young stellar populations just emerging from their natal molecular clouds? In this informal discussion we show that GAIA-DR2 data allow us to answer this question.

I will present results from a catalog of ~1.8 million Omega Cen member stars derived from DECam photometry covering a field of view of ~5x5 degrees  across the cluster and HST data for the innermost regions. The unprecedented accuracy of DECam photometry, the depth and field coverage, combined with HST data for the cluster core, allowed me for the first time to derive the global stellar density profile of Omega Cen based on star counts of red-giant and main-sequence stars from 1 to ~140 arcminutes.

The King and Wilson models fail to reproduce the outermost shape of Omega Cen density profile suggesting that the interaction with the Galactic tidal field and the presence of potential escaper (extra-tidal) stars need to be taken into account to explain the observations. The best fit of Omega Cen density profile is found with the SPES models which include potential escaper stars, confirming the presence of a stellar halo around the cluster. 

I will present the results of my master thesis project on quasar feedback and outflows, which have been submitted for publication to MNRAS and announced at https://arxiv.org/abs/1906.00985.

The Active Galactic Nuclei (AGNs) play a major role in the evolution of the galaxies, thanks to their ability to launch powerful outflows. The detection of nuclear X-ray winds, as well as ionised and molecular galactic outflows provide direct evidence of the so called feedback processes in action, whose physics is nevertheless poorly understood. 

I have studied a local AGN hosting a powerful nuclear X-ray wind, using ALMA observations in order to trace, at galactic scales, the molecular ISM kinematics. I found the signature of a possible molecular outflow with v~200 km/s that is potentially able to suppress the star-formation activity. By comparing the energetics of this putative outflow with that of the nuclear wind, I tested the blast-wave AGN feedback scenario favouring a momentum-driven outflow over an energy-driven model. 

I will introduce the scientific background, present the data analysis and discuss the possible interpretations of the results and their implications.

The discovery that stars in globular clusters do not fit within the traditional picture of hosting stars with the same age and chemical composition has led to a renewed interest in globular cluster studies. Indeed, it has been discovered that these complex systems host stars with variations in many elements like helium, carbon, nitrogen, oxygen, and sodium (a.k.a. multiple populations). Several scenarios have been put forward to explain the origin of the observed variations, but none of them is able to entirely reproduce observations. After more than 30 years from the discovery of multiple populations, their origin is still a mystery. In this talk, I provide an outline of observations of multiple populations and I attempt to highlight topics that are particularly uncertain and which new theoretical and observational studies are likely to lead to important advances.

Conceiving gravity as a force that emerges from an unknown microscopic structure, is a new paradigm. Recent progress in the description of gravity as an entropic force enables predictions/"post"-dictions for galaxy dynamics. When disks can be used to determine galaxy masses, these predictions are confirmed with an impressive precision, the well-known MONDIan phenomenology (Milgrom/Bekenstein).

However, deviations as "dark matter poor" or "dark matter rich" galaxies are found for elliptical galaxies. These are still obstacles for a satisfactory and more complete understanding of gravity. 

Any viable cosmological model in which galaxies interact predicts the existence of primordial and tidal dwarf galaxies (TDGs). In particular, in the standard model of cosmology (LCDM), according to the dual dwarf galaxy theorem, there must exist both primordial dark matter-dominated and dark matter-free TDGs with different radii. I use the hydrodynamical cosmological Illustris-1 simulation to identify tidal dwarf galaxy candidates and study their present-day physical properties. In particular, I will discuss the positions of galaxies in the radius-mass plane depending on their nonbaryonic content and compare it with observational data. I will explain the implications of the dual dwarf theorem for a LCDM cosmology. Finally, I will discuss the occurrence of NGC 1052-DF2-type objects.

How angular momentum is redistributed during accretion of material toward the central protostar is a key issue to understand the formation of stars, which is related to the disk formation, binary formation, as well as outflow launching. In this talk, I will report some of our recent results related to these topics, using high-resolution high-sensitivity observations of ALMA towards both low and high-mass protostellar objects. In the massive protostellar source G339.88-1.26, we detect rotational features in various molecular emissions. Based on their spatial distributions and kinematics, we find that they trace different parts of the envelope-disk system, such as the inner Keplerian disk, the outer Keplerian disk, and the infalling-rotating envelope surrounding the disk. These results indicate that an ordered transition from an infalling-rotating envelope to a Keplerian disk, accompanied by change of chemical composition, is a valid description, not only for low-mass protostellar sources as previous studies have shown, but also for massive sources, which supports a similar way of forming massive stars as low-mass stars. In the massive protostellar source IRAS07299-1651, the observations reveal a forming massive binary with an apparent separation of 180 au. From the line-of-sight velocity difference of the two protostars measured from hydrogen recombination lines, the binary is estimated to have a minimum total mass of 18 Msun, consistent with several other metrics. The hydrogen recombination line also reveals a rotating ring around the primary. The results suggest that disk fragmentation at several hundred au may have formed the binary, and much smaller disks are feeding the individual protostars. In the low-mass protostar NGC1333 IRAS4C, we detected a rotating outflow.  As the distance to the central source increases, the rotation velocity of the outflow decreases while the outflow radius increases, which gives a flat specific angular momentum distribution along the outflow. The mean specific angular momentum of the outflow is about 100 au km/s. Based on reasonable assumptions on the outward velocity of the outflow and the protostar mass, we estimate the range of outflow launching radii to be 5-15 au. Such a launching radius is more consistent with a slow disk wind launched from relatively large radii on the disk. These results provide promising targets for future close-up studies of disk formation, binary formation, and outflow launching, and how angular momentum is transferred among these components to allow accretion happens.

We will briefly report on the recent workshop “The VLT in 2030” which was held in Garching two weeks ago: https://eso.org/sci/meetings/2019/VLT2030.html. After the introduction, we will discuss what you may have learned at the workshop, if you attended, or answer questions you may have, if you did not attend the workshop.

Stellar feedback triggers galactic outflows and is a crucial component in simulations of galaxy formation. Galactic outflows contribute to the continuous interaction between galaxies and their surrounding medium, and allow for the interplay between stars and the different phases of the interstellar medium (ISM).

I investigate the impact of galactic outflow modelling on the formation and evolution of a disc galaxy, by performing a suite of cosmological simulations with initial conditions of a Milky Way-sized halo. In this talk, I will show how sensitive the general properties of the simulated galaxy are to the way in which stellar feedback triggered outflows are implemented, comparing results obtained by adopting different galactic outflow models. I will discuss the key requirements that a feedback model must have to be successful in producing a disc-dominated galaxy and the crucial importance of galactic outflows in reproducing observational features of present-day disc galaxies.

Also, I will show how the inclusion of AGN feedback impacts on the evolution of galaxies and on their properties, and I will discuss the key interplay between AGN and stellar feedback across cosmic time in cosmological simulations. I will focus on how feedback energy from the central BH couples to the different phases of the ISM, how the joint AGN and stellar feedback guarantees the large-scale cosmological accretion of gas on to the forming galaxy, controls the BH growth, triggers galactic outflows, and determines the BH-galaxy co-evolution. 

I will discuss the connection between chemical evolution and gas dynamics, to interpret observations of metal abundance in the ISM and circumgalactic medium. I will also present results that show the impact of the AGN feedback on the metal content of ISM and stars in galaxies, comparing predictions from my simulations with observations. 

It is often said that the Milky Way can serve as a 'model organism' to explore and understand the physical mechanism that shape galaxies from random initial fluctuations into the beautiful island universes we see today.

This statement is true, but easily said and much harder to make a reality. Over the last years I have collaborated with a number of students, post-docs and visitors at MPIA combining spectral surveys and now Gaia to turn this Galactic Archeology mantra into astrophysical insights.

In this talk I will synthesize some of this effort, focusing on two aspects of our Galaxy's main component, its disk: what sets the overall radial profile of the disk,  and what sets its vertical structure? The answers to both questions are linked to the question of how much dynamical memory loss our Galaxy has incurred --  its exceptionally quiescent history. I believe we are now considerably closer to understanding why disk galaxies look the way they do.

The cosmic microwave background (CMB) has proven to be a powerful probe of the physics and cosmology of our universe. CMB observations are helping to address fundamental questions, such as the nature of dark energy and dark matter, and are being used to constrain the physics of inflation at energies a trillion times higher than the Large Hadron Collider. Recent measurements have led to exciting progress in several areas, from improved constraints on cosmological parameters via CMB polarization to the discovery of galaxy clusters and characterization of their large-scale velocities. One focus of our current research is combining measurements from the Atacama Cosmology Telescope (ACT) with optical galaxy surveys to characterize pairwise galaxy cluster velocities. Beyond the ACT, the CCAT-prime and Simons Observatory projects are building six-meter-aperture ultra-high optical throughput telescopes to illuminate many times more microwave detectors than existing telescopes. With CCAT-prime we plan to pursue new galaxy cluster and carbon intensity mapping measurements to understand the epoch of reionization in addition to CMB research. These high-throughput telescopes are designed to work together with smaller aperture telescopes in a next generation “Stage-IV” CMB survey, which we will use to probe models of inflation, light relics, and cosmic structure with unprecedented precision.

Understanding the processes of gas flows in and out of galaxies is crucial in galaxy evolution studies. Yet, observations of the faint and diffuse Circum-Galactic Medium (CGM), where these processes take place, remain challenging.

The most efficient approach to detect this faint and diffuse gas is in absorption towards bright background quasars. However, to investigate the CGM we need to also identify the galaxy counterpart and connect it to the absorption feature.

In this context we characterised counterparts to Damped Lyman-alpha Absorbers (DLAs) at z~1 using HST broad-band images. We measured their stellar masses and find them to be generally less massive than the average galaxy population. We also discovered their complex morphology and environments, challenging the interpretation of CGM studies in absorption.

Beyond absorption, prospects to map the CGM in emission will offer new information on its extent and clumpiness. To optimise observing strategies of the CGM in emission, we have made predictions from dedicated cosmological zoom-in RAMSES simulations. We post-processed galaxy halos with an emission model to create mock integral field observations. Using the instrument model, our results indicate that ELT/HARMONI will enter a regime of low surface brightness typical of the CGM which is not attainable with current facilities.

In recent years, the number of known galaxy clusters at high redshift has grown dramatically thanks in large part to the success of surveys utilizing the Sunyaev Zel'dovich effect. In particular, surveys carried out by the South Pole Telescope have facilitated the discovery of hundreds of new distant clusters, allowing us to trace, for the first time, the evolution of clusters from shortly after their collapse (z~2) to present day (z~0). In this talk, I will highlight recent efforts by our group to understand the observed evolution in the most massive clusters, including: the enrichment history of the intracluster medium, the merging history of clusters, the cooling and formation of cool cores, the growth of central cluster galaxies, and the evolution of the central radio-loud AGN.  In addition, I will attempt summarize the current state of ongoing and planned SPT surveys, and the synergies with current and future observatories including eRosita and Athena.

Powerful quasars can be seen out to large distances. As they reside in massive dark matter haloes, they provide a useful tracer of large-scale structure. Stacking far-infrared and sub-millimeter maps on the locations of quasars has proved a useful tool in studying quasars and their environments. We stack Herschel-SPIRE images at 250, 350, and 500 μm at the location of 11,235 quasars in 10 redshift bins spanning 0.5 ≤ z ≤ 3.5. The unresolved dust emission of the quasar and its host galaxy dominate on instrumental beam scales, while extended emission is spatially resolved on physical scales of order a megaparsec. This emission is due to dusty star-forming galaxies (DSFGs) clustered around the dark matter haloes hosting quasars. We measure radial surface brightness profiles of the stacked images to compute the angular correlation function of DSFGs correlated with quasars. We then model the profiles to determine large-scale clustering properties of quasars and DSFGs as a function of redshift. We adopt a halo model and parametrize it by the most effective halo mass at hosting star-forming galaxies, finding log(M_eff/M_⊙)=(13.8+/0.1) at z = 2.21-2.32, and, at z = 0.5-0.81, the mass is log(M_eff/M_⊙)=(10.7+/-0.2). Our results indicate a downsizing of dark matter haloes hosting DSFGs between 0.5 ≤ z ≲ 2.9. The derived dark matter halo masses are consistent with other measurements of star-forming and sub-millimeter galaxies. The physical properties of DSFGs inferred from the halo model depend on details of the quasar halo occupation distribution in ways that we explore at z > 2.5, where the quasar HOD parameters are not well constrained.

The earliest stages of star formation begin with the gravitational collapse of a molecular cloud core to a protostar and circumstellar disk, both surrounded by an extended envelope of gas and dust. The protostar assembles most of its mass through accretion from the disk during its youngest, deeply embedded period, with the accretion rate expected to be variable due to disk instabilities, planet/companion interaction, and other mechanisms. However, direct constraints on the accretion rate for the youngest stage are difficult to obtain in the optical and near-IR due to extinction by nascent dust. Millimeter observations can indirectly trace changes in the accretion rate by monitoring the temperature response of the dusty disk and envelope to a change in the accretion luminosity. The strongest response is expected at the spatial scales of the disk, which can be measured using the the high resolution provided by the Atacama Large (sub)Millimeter Array (ALMA). In this seminar, I will discuss techniques for time domain surveys with interferometers, and present preliminary results from our ongoing ALMA surveys to measure accretion variability in a sample of deeply embedded protostars.

The Milky Way halo consists of old and metal-poor stars amidst bound substructures such as globular clusters and satellite dwarf galaxies. A comparison of stellar abundance ratios and kinematics between typical halo stars and these bound substructures reveals many interesting patterns that give us clues about their chemical evolution - a process called Galactic archaeology. The lowest metallicity stars that still exist today probably carry the imprint of very few supernova and push Galactic archaeology to its limits. These stars represent our best observational approach to understand the First Stars and the early Galaxy. In this talk I will review cosmological modelling predictions for observations of these very old and metal-poor stars as well as observational efforts and results. In particular, I will present results of the Pristine survey, a Franco-Canadian photometric survey of the Milky Way halo designed to efficiently decompose the metallicity structures of the Milky Way halo. I will show how we can use this great discriminatory power to hunt successfully for the very rare extremely metal-poor stars, to study metal-poor dwarf galaxies, and to search for stellar structures in the halo.

Observational astronomy, a field several thousand years old, has been dominated for most of its history by the human eye, which acted as both optics and detector. Important discontinuities provided enormous advances both in collecting area and detectors (e.g. the telescope, photographic plates, solid state detectors etc), increasing immensely the parameter space of discovery. Today most of these advances are close to their full potential and new progress is mostly predicated on ever larger telescopes. I will give a brief overview of the history of the field, discuss some of the solutions developed to produce larger and larger primaries and describe some of the science driving this effort. Finally, I will touch on the current development of Extremely Large Telescopes and on future possibilities.

How and when the stellar mass content of galaxies is assembled is still one of the main questions of galaxy evolution studies. The existence of a very tight relation between the galaxy star formation rate (SFR) and the stellar mass (M*) suggests that most galaxies form their stars at a level mainly dictated by their stellar masses and regulated by secular processes. Such relation, called the Main Sequence (MS) of star forming galaxies, is in place from redshift ~0 up to ~4 and it is considered one of the most useful tools in astrophysics to study the evolution of the  star formation activity in galaxies.

More than 500 papers in the literature explored in the past 15 years, with a variety of star formation rate indicators and techniques, how the slope and scatter of the relation evolve across cosmic time. I will show that, when all of the selection effects are taken into account, all these results point to a rather consistent  picture, with surprising consequences for the cosmic star formation history of the Universe.

X-ray binaries, composed of a compact object (neutron star or black hole) orbiting around a companion star, constitute an excellent environment to study accretion phenomena, one of the most promising challenges in modern astrophysics. Outstanding open topics include the interplay between outflows (in the form of collimated winds or relativistic jets) and discs, the accretion-radiation energy balance, the radiative feedback and the relation between relativistic jets and the fundamental properties of the black holes (e.g. spin). Here, we report the analysis of two black hole low mass X-ray binaries, 4U 1630-47 and IGR J17091-3624, using X-ray high-resolution spectra. In the case of 4U 1630-47, we found that the absence of lines in the transitional state cannot be attributed to an evolution of the plasma caused by thermal instabilities. For IGR J17091-3624 we identified a local X-ray absorber during a hard-intermediate accretion state. This is the first detection of a local not-outflowing absorber simultaneously with a compact jet emission.

While ancient scientist often have patrons to fund their work, peer review of proposals for the allocation of resources is a foundation of modern science. A very common method is that proposals are evaluated by a small panel of experts (due to logistics and funding limitations) nominated by the grant-giving institutions. The expert panel process introduces several issues - most notably: 1) biases introduced in the selection of the panel. 2) experts have to read a very large number of proposals given a very limited time. Distributed Peer Review promises to alleviate several of the described problems. In this process, the task of reviewing is distributed among the proposers. Each proposer is given a limited number of proposals to review and rank. The process promises – among others – making grant allocation more transparent, making the voices of junior scientists heard, and lowering the load of review tasks on the senior academics. We present the result of an experiment running a distributed peer review process for allocation of telescope time at the European Southern Observatory. We have introduced several enhancements to the ‘classic’ distributed peer review, including using natural language processing and machine learning algorithms in identifying research expertise, and the addition of a step to provide an evaluation of the reviews encouraging the reviewers to provide useful feedback. The results of our experiment show a very high success rate in predicting the expertise of reviewers given proposals. The general experience has been overwhelmingly praised by the participating community (using an anonymous feedback mechanism). I will give an overview of our experiment in this talk.

Pyxel is a novel, end-to-end detection chain simulation framework in Python, designed to host and combine existing and new models, i.e. code simulating instrumental effects such as optical diffraction, charge deposition by cosmic rays, charge diffusion, detector Point Spread Function, readout noise sources, Charge Transfer Inefficiency in CCDs or persistence in CMOS-based imaging detectors.

This simulation framework has been developed in order to alleviate the need for re-developing a new specific simulation tool for every new instrument onboard space mission or ground observatories and instead share and transfer resources and knowledge.

Pyxel is an easy-to-use, flexible and multi-purpose tool to support instrument development during all phases, e.g. to generate synthetic data, support data processing and analysis , estimate performance, understand criticalities, investigate problem areas or trade between different technologies.

It is developed at the European Space Agency in collaboration with the European Southern Observatory, and will be released soon as an open-source software. Our goal is to establish a worldwide collaboration based on Pyxel to share simulation codes and resources, initiate and facilitate the knowledge transfer within the instrumentation community.

In a reprise of the famous 1919 solar-eclipse experiment that confirmed general relativity, the nearby white dwarf Stein 2051B passed very close to a 19th magnitude background star in 2014. As it passed in front, Stein 2051B caused a deflection of the background star's image by ~2 milliarcsec, which we observed with HST at 8 different epochs. This allowed us to determine the mass of Stein 2051B using this technique of astrometric microlensing for the first time outside the solar system. Our measured mass of Stein 2051B, the sixth- nearest white dwarf, provides confirmation of the physics of degenerate matter, and lends support for white-dwarf evolutionary theory. The recent Gaia data allow accurate prediction of many such upcoming events which can be used to determine accurate masses of single stars.

There are now a long list of direct imaging “planet” discoveries (some with question marks in their title) that have shown to be unexpected infrared disk features. These objects include T Cha, LkCa 15 and HD 169142. I will outline why these features were unexpected based on naive radiative transfer models, and why the planet hypothesis was often preferred in the past. I will show that our current knowledge of the distribution and luminosity of giant planets explains why direct imaging is so hard, will explain how disk features can be much brighter than previously expected due to “exotic” dust compositions, and how radiative acceleration, dust settling and gas drag sorts dust grains to create such “exotic” dust. Finally, if I haven’t run out of time, I will discuss alternative approaches to detecting giant planets, in particular spectro-astrometry of accretion shocks in the context of objects like PDS 70 and GSC 6214b.

A basic introduction is given to optical and IR detectors for ground based astronomical instrumentation. This will include a bottom up description of the techniques employed by the manufacturers to give the very best performance demanded by us.

It will also include a brief description of the external detector electronics required to drive these beasts as well as touching on some of the characterisation testing we do here at ESO. Real devices will be on show.

Stars constitute the building blocks of much of the visible Universe, therefore the understanding of their evolution and nucleosynthesis is a key astrophysical goal for the future. In particular, the knowledge of the structure, evolution and nucleosynthesis of stars, both as single objects and as part of stellar aggregates, is crucial for our understanding of the chemical evolution of the galaxies, of the resolved stellar populations in Galactic and extragalactic environments, for the definition of standard candles to be used in the cosmic distance ladder, for robustly measuring ages, for dating the oldest stellar systems and in turn the universe itself.

However, despite the great effort of several groups over the last 30 years devoted to achieve a satisfactory level of accuracy and reliability of the stellar evolutionary codes, the predictive power of the present stellar models is still limited by a number of uncertainties due to the poor knowledge of some fundamental physical phenomena.

In this talk I will review the current status of the most updated stellar models, their uncertainties and what we plan for the future to improve the most important limitations of their predictive power.

Journey with a space-race geek who never got to see a Saturn V fly and still won't forgive himself for missing a Space Shuttle launch. We're going to the Moon, Apollo-style — I’ll bring the Lego.

Journey with a space-race geek who never got to see a Saturn V fly and still won't forgive himself for missing a Space Shuttle launch. We're going to the Moon, Apollo-style — I’ll bring the Lego.

Journey with a space-race geek who never got to see a Saturn V fly and still won't forgive himself for missing a Space Shuttle launch. We're going to the Moon, Apollo-style — I’ll bring the Lego.

Journey with a space-race geek who never got to see a Saturn V fly and still won't forgive himself for missing a Space Shuttle launch. We're going to the Moon, Apollo-style — I’ll bring the Lego.

The presence of Raman-scattered laser guide-star photons above the VLT was first reported in 2017. Here, I will present the outcome of a series of dedicated follow-up observations of the 4LGSF up-link laser beams acquired with MUSE and ESPRESSO.

From a series of MUSE observations acquired over a 27 month period, we find evidence that dust on the primary and secondary mirror of the telescope is responsible for up to (60+-5)% of the laser light contaminating MUSE WFM-AO observations. As such, laser lines provide an ideal, non-invasive means to monitor the scatter properties of the UT4 telescope mirrors on a sub-nightly basis. This could allow, for example, to assess (with a single metric) the qualitative impact of operating with high-particle counts, and the ability of CO2 cleanings to mitigate long-term consequences.

In February 2018, we used ESPRESSO to acquire a high-resolution (R~140'000) spectra of one 4LGSF up-link laser beam. The richness of the Raman spectra associated with the laser beam, revealed in a spectacular fashion by ESPRESSO, provides an ideal and unique means to characterize the as-built accuracy of the ESPRESSO spectrograph.

Altogether, these observations demonstrate that laser guide-star systems at astronomical observatories ought to not only be thought of as mere sub-components of complex adaptive optics systems, but also as powerful monitoring tools and accurate spectral calibration sources: both for existing and upcoming facilities.

With available X-ray surveys getting to extreme deep levels with Chandra (~1e-17erg/s/cm2) and probing harder energies with NuSTAR (8-24keV), one may wonder how JWST or ALMA will contribute to obscured-AGN demography. Although deep spectroscopy will be enabled with spectroscopic instrumentation on board JWST (especially with MIRI) and ALMA, such modes are still regarded as follow-up tools for this purpose. This presentation aims at showing how deep high-spatial resolution NIRCam and MIRI broad-band imaging combined with ALMA can excel in what obscured-AGN demography and host-characterisation is concerned with respect to what is currently achieved by X-ray surveys. I will show one way to pursue a telescope-time-efficient survey aiming at selecting AGN up to redshift 2 (and potentially to redshift 6), and what currently planned JWST GTO and ERS projects lack in that regard. Extra science questions such a JWST-ALMA team-up could address in addition "for free" (e.g., high-redshift source selection) will be briefly highlighted.

Dynamically important magnetic fields have been shown to play pivotal roles in processes that are closely linked to galaxy evolution. However, how galaxies and their magnetic fields have co-evolved since the early Universe remains an unsolved fundamental question in astro-plasma physics and cosmology. In this talk, I will describe how the advent of broadband radio polarimetry is revolutionizing the field of cosmic magnetism by enabling unambiguous and precise polarization measurements. Then, I will highlight several innovative studies on mapping galactic magnetic fields near and far: from the Milky Way/ nearby galaxies to distant galaxies. I will conclude by discussing the exciting prospects of decoding the origin and evolution of cosmic magnetic fields with Spare Kilometre Array pathfinders and the next generation radio telescopes.

Since its discovery by Henize (1956), numerous observations have been made of the supergiant B[e] star LHA 115-S 18 (S18). The optical spectrum of the star is characterised by strong emission in the Balmer series and prominent He I lines as well as a wealth of forbidden and permitted low excitation metallic lines. Following the behaviour observed in other sgB[e] stars, the high excitation lines are broader than the metallic lines and exhibit pronounced variability in profile and strength – the Balmer lines evolve from (asymmetric) single peaked to P Cygni profiles and vary in strength by a factor of ∼3 (Zickgraf et al. 1989; Nota et al. 1996). The most dramatic variability, however, is seen in the He II 4686 Å line, which has been observed to transition from absence to being comparable in strength to H Beta, with such changes occurring over short timescales (of the order of months; Shore et al. 1987). Clark et al.(2013) used archival spectroscopic and photometric data to show that whilst S18 trivially satisfies the eponymous classification criteria of LBVs, it does not conform to their typical behaviour as outlined by Humphreys & Davidson (1994): The photometric variability occurs at unprecedented rapidity and these spectral and photometric changes appear completely uncorrelated, in stark contrast to the behaviour of normal LBVs. S18 has been detected at X-ray wavelengths both by Chandra (in 2002) and XMM-Newton in (2003) with L_X~10^33 erg/s, however, in a deeper XMM observations in 2006, the source was undetected, suggesting a factor 10 variability at X-ray wavelengths.

Since mid 2014, S18 has been monitored spectroscopically, with the Southern African Large Telescope (SALT), and photometrically as part of the OGLE project then the by the Remote Observatory in the Atacama desert (ROAD). In July 2018 a VLT XSHOOTER spectrum revealed that the source was transitioning into its ''hot'' state (in which He II 4686 A is at maximum), a state never monitored and a transition that has never before been observed. We were granted a further 10 hours of observations with XShooter and 14 hours with SALT. The target is also being monitored at X-ray wavelengths as part of the Swift monitoring of the High Mass X-ray Binary population of the SMC. Far from finally revealing the nature of this enigmatic target, however, this dataset, and specifically the XSHOOTER data, has revealed yet more unexpected and unexplained behaviour including a strong UV excess at wavelengths < 360 nm, similar to those reported in Young Stellar Objects (Manara et al. 2016). In this discussion session, I aim to summarise all the data from this "outburst" and, with the help of the participants, finally find an answer to the question "What is LHA 115-S 18?"

Central and satellite galaxies are strictly connected to the global and local properties of their host halo, although in very different ways. While the stellar mass of the central galaxy is tightly correlated with the host halo mass, satellites might go through a complex mix of processes involving the erosion of their hot and cold gas and stellar component.

I will show how these connections can be used to understand the distribution of galaxies in the SFR-stellar mass plane up to z~1.2 using SDSS and COSMOS data. I will show that the Main Sequence of star forming galaxies and its scatter as a function of stellar mass are consistent with a re-scaled version of the local relation and distribution, shifted at higher values of SFR according to (1+z)^3. The relations bends at high stellar masses, where central galaxies of massive halos, as groups and clusters, dominate in number. Low mass satellite  dominate the region of quiescence at very low star formation activity at any redshift. I will argue that the MS bending at the high stellar mass end is due to two processes: i) the formation of a bulge component as a consequence of the increased merger rate in groups and clusters, and ii) the cold gas starvation induced by the hot halo environment, which limits the gas inflow onto the disk. The latter process leads to a systematic decrease of the availability of molecular gas at any stellar mass in groups and clusters with respect to lower mass halos. Similarly, the increase of the MS scatter at high stellar masses is explained by the larger spread of star formation histories of central group and cluster galaxies with respect to lower mass systems.

Simulations of planet-disk interactions have long predicted that giant protoplanets can induce the formation of rings, spiral arms, and high contrast asymmetries in protoplanetary disks, but for most sources it only recently became possible to detect such structures with the advent of high-resolution, high-sensitivity telescope facilities. I will present the results of the Disk Substructures at High Angular Resolution Program (DSHARP), the first high angular resolution ALMA survey of protoplanetary disks. Concentric rings and gaps are the most common type of substructure observed and can be found in disks spanning a wide range of ages and stellar host spectral types. A small fraction of disks also feature spiral arms or high-contrast asymmetries. The widespread presence of these complex substructures in young disks suggest that giant planet formation may occur readily within a million years. The results of  DSHARP, in conjunction with other recent ALMA studies, suggest that high angular resolution millimeter wavelength observations will be key for characterizing young planet demographics.

Artifacts, background noises, mosaic overlaps, HDR looks, color balance, more exposures, frame composition, etc. are all issues which removing/improving them completely might not affect your scientific output but could help significantly to share your science with the world outside. The discussion will look into the visual improvements which could be done on images by scientists as part of post-processing and data reduction. The talk will be also a quick surf on deep waters of scientific image processing for outreach purposes at ESO.

We now know that exoplanets abound in the Galaxy, with most stars hosting at least one planet. These recently discovered worlds are much more diverse than the planets in the Solar System, and raise many questions about their formation, evolution, and habitability. To address these questions, we turn to atmosphere characterization, which provides a wealth of additional information about the planets. I will discuss the state of the art in atmosphere studies, focusing on recent high-precision, space-based observations of hot Jupiters and warm Neptunes. These studies have already revealed planetary atmospheric chemistry, climate, and cloud coverage in unprecedented detail, and they are poised for a revolutionary advance thanks to a series of new and upcoming missions. I will conclude with a discussion of prospects for characterization of temperate, terrestrial worlds with future facilities.

Directly detection of radiation from extrasolar planets is the premier method for determining exoplanet atmospheric composition. Direct detection of young giant planets can also probe formation processes near the snow line, which is thought to be where giant planet formation is most likely. Existing instruments have largely failed at detecting a significant population of giant planets. I will outline why they have failed, and what is needed to significantly change this and open up a new subfield of observational exoplanet research. I’ll outline the potential for a METIS and a high contrast VLTI instrument (Hi-5/VIKiNG), and describe why eventually space interferometry is needed. I’ll finish by outlining a pathway for space interferometry, and describe why it isn’t has hard as you might think.

The distribution of planetary companion masses, as well as the integrated surface density of companions over fixed mass ranges provide a wealth of information concerning planet formation processes as well as the subsequent dynamical evolution of planetary systems.  However, decoding this information requires large samples of host stars of differing mass.  Here we review recent direct imaging results (e.g. Reggiani et al. 2016) combining predictions for planetary mass distributions as well as very low mass brown dwarf binaries suggesting a local minimum in the companion mass ratio distribution.  We also present preliminary results for the on-going SPHERE SHINE imaging survey on the ESO VLT (Vigan et al. in preparation).  Using constraints on the surface density distribution of gas giant planets we can fit results from radial velocity, imaging, and other techniques with a log-normal that peaks between 1-10 AU (e.g. Meyer et al. 2018).  Finally, we discuss the implications of these results (the local minima in the companion mass ratio and the local maxima in derived surface density distribution of gas giant companions) as a function of stellar mass.  We explore whether gas giant planet mass functions could be universal when considered in ratio to the host star mass and highlight areas where further work is needed.

I will review some of the common methods for model selection: the goodness of fit, the likelihood ratio test, Bayesian model selection using Bayes factors, and the classical as well as the Bayesian information theoretic approaches. I will illustrate these different approaches by comparing models for the expansion history of the Universe. I will highlight the premises and objectives entering these different approaches to model selection and finally recommend the information theoretic approach.

It was always hoped that one day we would be able to use Gaia data to pin down the matter distribution in the Milky Way, measure the Galactic accretion history, find new previously unseen dwarf galaxies with unprecedentedly low surface brightnesses and track narrow stellar streams to gauge masses of Dark Matter sub-halos. I will show that all of these hopes came true with the last year’s Gaia Data Release 2.

We compare resolved and unresolved observations of the CO and dust continuum emission from star-forming galaxies at z~2. The molecular gas phase of the interstellar medium is a crucial component of star-forming galaxies, hosting, and providing the fuel for, star formation. Constraining the total mass and spatial distribution of molecular gas is therefore critical to understanding the evolutionary state of a galaxy, which can be characterised by how efficiently, and where, star formation is occurring. To determine the total molecular gas mass of high-z galaxies, the community currently relies on two main approaches: measuring either (1) a CO line luminosity, or, (2) dust continuum emission. These molecular gas tracers have been observed for large samples of high-z galaxies with ALMA, and it is assumed that the two lead to equivalent measurements of the molecular gas content. But, recent low-resolution imaging indicates that the CO and dust continuum may trace different galactic regions, with the dust continuum emission being more centrally concentrated. In this talk I will present our comparisons of the CO and dust-derived molecular gas properties of Main Sequence galaxies at z~2 and will discuss the implications for future molecular gas studies with ALMA.

We will discuss simulation outputs from projects such as IllustrisTNG -- what kind of data exists, and how it can be analyzed. I will go quickly through how to use the IllustrisTNG public data release (online), including its documentation, getting started tutorials, and examples for data analysis.

I will lead a short hands-on tutorial showing some basic data analysis. If you wish to follow along (recommended), please bring your laptop. Before Monday, please register for a TNG data release account if you don’t have one already. After this has been approved, please then request access to the JupyterLab service, which I will use for the tutorial. We won’t have time to do any of this on Monday morning. This will be in Python, although it is also possible to work in IDL or Matlab.

We can discuss how to compare the simulations to any type of observation that people may have, and other topics of interest.

We review the status of the Supernova/Gamma-Ray Burst connection. Several pieces of evidence suggest that long duration Gamma-ray Bursts (GRBs) are associated with type Ic Supernovae (SNe). Current estimates of SN and GRB rates show that only a tiny fraction of massive stars, likely less than 2%, are able to produce GRBs. The reasons for this small ratio will be discussed.

In the last 6 months, the VLTI/GRAVITY and Event Horizon Telescope experiments have ushered in a new era of spatially resolved studies of event horizon scales around massive black holes. I will discuss the experiments, their first results, and the implications for understanding the role of magnetic fields in black hole accretion and jet launching and for future tests of strong field general relativity.

BLAST-TNG is a long-duration, high altitude, balloon-borne telescope scheduled to fly in the 2019-2020 season from Antarctica. The data from the 28 day flight will provide new insight into the properties of dust and the role of magnetic fields and its role in the star formation process. BLAST-TNG will observe the sky at three difference wavelength, 250um 350um and 500um, with more than 3000 polarization sensitive KIDs (Kinetic Inductance Detectors) cooled at 270mK.

It is now well established that globular clusters (GCs) host unusual chemical patterns in the form of star-to-star abundance variations in light elements. However, the origin of such multiple stellar populations (MPs) is still far from being understood. The detailed characterisation of MPs is fundamental in our understanding of GC formation, which in turn has consequences for the formation and evolution of galaxies. To this purpose, we have undertaken an HST photometric survey of 13 star clusters in the Magellanic Clouds (MCs) with masses comparable to that of old GCs where MPs have been identified, but with significantly younger ages (from 1.5 - 11 Gyr). We found that the extent of the MPs (in both chemical spread and in the number of stars that show the chemical anomaly) are a strong function of age, with older clusters having more extreme populations. Another surprising result is that we find MPs down to ~2 Gyr old clusters for the first time. This is fundamental as it shows that the formation of MPs is not restricted only to the early Universe, but it continued down to a redshift of at least z=0.17.  This provides another strong link between young massive clusters and the ancient globular clusters, suggesting a common formation/evolution mechanism.  The results presented here represent fundamental constraints for the origin of MPs and might point towards a new and fresh direction into the onset of this complex phenomenon.

Quasars are now thought to have made critical impact on galaxy formation. Feedback from accretion onto supermassive black holes is frequently implicated in establishing the black hole mass vs galaxy bulge correlations and in limiting the maximal mass of galaxies. In this talk, I will review the indirect evidence for quasar feedback as required by galaxy formation models. I will then review the recent progress on detecting direct evidence for quasar-driven outflows and other types of feedback through multi-wavelength observations. These data may provide direct observational evidence for one of the long-standing paradigms in galaxy formation.

The mass of the Milky Way is one of its most fundamental properties, important for understanding the MW itself, the past and future of the Local Group of galaxies, and where the MW sits in a cosmological context. Yet mass estimates in the literature are significantly scattered and many estimates differ by more than their uncertainties. Mass estimates rely on accurately measuring total velocities of objects within the MW, but historically we have only been able to measure one component of motion, leaving two components unknown. However, this has changed thanks to recent proper motion measurements from HST and Gaia. I will talk about why knowing the mass of the MW is so important, how we can measure it, why there has been such disagreement in the past, and how recent HST and Gaia measurements are finally bringing better agreement.

Brown dwarfs (BDs) bridge the mass range between low-mass stars and Jupiter-like planets. BDs are relatively abundant in star forming regions and in the field, but their formation mechanism is still under debate.  Some theoretical descriptions and observational findings support the idea that stars and BDs share a common formation history, but the observational evidence is still not enough to distinguish the competing formation models. The study of the earliest phases of BD formation, the proto-BD phase, when they are still embedded in the parental cloud, and finding BDs formed in isolation with similar properties to low-mass stars would strongly support the star-like scenario as the primary formation mechanism. Our group started more than ten years a project to search and characterize very young proto-BD through a systematic and multi-wavelength exploration in nearby star-forming regions. I will show some of the results of the collaboration that has found a few tens of candidate proto-BDs in Taurus, Barnard 30, and Chamaeleon II, which begin to point out to the formation of BDs as a scaled-down version of low-mass stars.

Core Collapse Supernovae are the endpoint of the evolution of massive stars (M > 10 Msun). They play a fundamental role in the evolution of the Universe because, among the other things, contribute to the production of most of the elements (especially those necessary to life), induce star formation when the shock wave following the explosion passes though the interstellar medium, produce neutron stars and black holes, are connected to the GRB events (some of them) and last, but not least, are one of the sources of gravitational waves. Therefore, a good knowledge of these events are needed to shed light on many astrophysical topical subjects.

In this lecture I will mainly focus on the role of core collapse supernovae in then chemical evolution of the matter and, in particular, on the nucleosynthesis occurring during the explosion. I will describe the basic principles of the nuclear burning at high temperatures coupled to the dynamics of the exploding mantle of the star and will show the main products of the various explosive burning.

For sake of completeness I will also briefly discuss the chemical composition of the final ejecta, how it depends on the progenitor star and on the remnant mass. Finally, I will show which is the contribution of a generation of massive stars (i.e., core collapse supernovae) to the global enrichment of the interstellar medium.

Our view of the gas and its physical conditions in the central region of AGN has been enriched by the discover of fast and massive outflows of HI and molecular gas. These outflows can be driven by radiation/winds but also by the interaction of the radio plasma with the ISM. Understanding the origin and quantifying their impact requires to trace their location and derive their physical conditions (density of the gas, mass, mass outflow rate and kinetic energy of the outflow etc.). Particularly interesting has been the finding that in the first phase of their life, jet in radio galaxies can be particularly effective in driving such outflows. This crucial phase is at the heart of the idea of feedback, therefore particularly relevant for studying feedback in action.

In this talk, I will present some of the results we have obtained to trace jet-driven HI and molecular gas outflows down to scales ranging from hundred to tens of pc. The impact of low-power radio jets will be discussed and the comparison with the predictions from numerical simulations will also be presented. Outflows of up to 100 Msun/yr have been found in molecular gas using ALMA while the HI observed with VLBI is showing that the outflowing gas is clumpy as also predicted from numerical simulations. I will describe the kinematics of the gas and its conditions and the relevance they may have for feedback.

Numerous models of galaxy evolution expect that AGN should have a negative feedback effect on star formation in their host galaxy, by injecting energy into the ISM in the form of powerful outflows. In this informal discussion, I will focus on observational evidence of multi-phase outflows in optical spectra of nearby AGN. In particular, I will show which are the best tracers of ionised and atomic outflows among emission and absorption lines commonly observed in optical spectra. Then, I will talk about general outflow properties and their connection with AGN activity. In the last part, I will discuss gas mass outflow rate and related energetics, generally used to estimate the feedback impact on galaxy evolution.

The halo system of the Milky Way is a precious laboratory because it provides unique elemental abundances and kinematic information on the first objects formed in the Universe and encoded in the ancient stars that populate this complex structure. All this information can be used to tightly constrain models of galaxy formation and evolution. In this talk, I will focus on the age distribution and age gradients in the halo system and I will discuss possible formation scenarios of the Galaxy based on these results.

This talk presents the crucial role that type-I Cepheid variable stars play in improving the understanding of how stars and the cosmos evolve. Starting from the recently reported Hubble constant tension that may imply a need for new physics beyond standard cosmology, I will describe ongoing efforts to measure H0 with an accuracy of 1%. Specifically, I will present an ongoing large observing program operating on both hemispheres that has measured more than 19,000 high-precision radial velocities of Cepheids in support of accurate parallaxes and alternative distance estimates based on Baade-Wesselink-type methods. After highlighting the impact of binaries for accurate parallax determination, I will show that stars physically associated with Cepheids contribute a modest photometric bias of less than 0.23% to H0, which may be further reduced in the future. The second part of the talk discusses Cepheids as sensitive stellar laboratories that probe the effects of rotation on stellar evolution in general and in the context of predicting properties of Cepheid populations, such as the period-luminosity-relation. Time permitting, I will present the curious case of Polaris, our nearest Cepheid, whose Gaia-based luminosity estimate and multi-periodic variability seem to defy theory, thus underlining the urgent need for a more detailed astrophysical understanding of our most important standard candles.

Adaptive Kernel proved to be valuable in the evaluation of 1D profiles of positive additive distributions in inverse problems. This includes modelling photon fluxes as well as heat fluxes from plasma to the surrounding wall in fusion research. This multi-resolution concept is extended to 2D evaluation, aiming at inverse problems arising in the analysis of image data. Approaches for tackling the problem with optimisation routines as well as "classic" Random Walk and Hamiltonian Monte Carlo integration are presented.

For more than 20 years helioseismology, the study of solar oscillations, has provided an exquisite picture of the solar interior structure. However these oscillations, which are standing acoustic waves in the solar interior, have diminishing amplitudes towards the deep interior and render a blurred picture of the solar innermost core, where most nuclear reactions take place and neutrinos are produced. During the last decade, after the discovery of neutrino oscillations, solar neutrino experiments such as SuperKamiokande, SNO and especially Borexino have continued to develop and improve the accuracy and precision of measurements solar neutrino fluxes. Helioseismic and neutrino constraints offer complementary views of solar interiors and open up the best possibilities to date for testing solar (and stellar) evolution theory as well as a laboratory for particle physics.

The talk will first review the current status of (standard) solar modeling in the context of helioseismic constraints, and discuss where problems and uncertainties lie. About the latter, some emphasis will be placed on recent calculations and experiments of radiative opacities that impact solar and stellar modeling. The second part of the talk will present results of solar neutrino experiments, focusing on Borexino's capabilities to perform solar neutrino spectroscopy, and the constraints on solar interior models that can be obtained. The third part of the talk will briefly discuss the relevance of solar model uncertainties for evolution of low mass stars and the uncertainties in determination of stellar properties based on asteroseismic results might be affected. A short final part will include a discussion of the recent claims of detection of gravity modes (g-modes) in solar oscillations.

The study of the inner gaseous disc of YSOs is crucial to understand the physical processes ruling disc evolution and its connection with planet formation. In this talk, I will present our results on the inner disc properties of the CTTS RW AurA. The RW Aur system has captured the attention of astronomers for its dimming events. By using X-SHOOTER spectra obtained when the star was in a bright and in a dim state, we compare the NIR CO emission in order to shed light on this mystery. In general, the NIR CO emission traces a warm (T=2000-5000K) and dense (NCO>1e12cm-2) gas as expected in the innermost region of discs. Both states need a cool (T=2600K) and dense (NCO=7e20cm-2) gas to reproduce the observations, with the emitting region located just inside the dust sublimation radius. By comparing the SED (from ~300 to ~1000 nm) and the CO emission of both states, we find that the dimming can be due to absorption by a layer of large grains with optical depth slowly declining from 2.8 to 1.6. The accretion rate remains constant (Macc~2e-8 Mo/yr) if one assumes that the same layer of dust also occults the accretion line emitting region. This excludes accretion bursts as the main cause of RW AurA brightness variability.

Supermassive black holes are found inside all massive galaxies. As these black holes grow (through mass accretion) tremendous amounts of energy is released. Current galaxy evolution theory states that this energy must couple to the gas in the host galaxy (and beyond) and consequently heat the gas or driving it away through outflows. Without this so-called “AGN feedback” models cannot reproduce realistic galaxy populations. However, trying to observationally constrain this process has been an on-going challenge for the last two decades. In this KES I will give a simplified overview of the status of the research on AGN feedback, including the different approaches taken by observers and theorists. Most importantly I will try to provide some clarity on what can be considered a very confusing topic to those outside the field!

Star formation takes place in the densest and coldest parts of the interstellar medium (ISM), in dark molecular clouds. These are swept up by multiple supernova explosions on scales of several hundred parsec. While condensing out of the warm ISM, the clouds are continuously fed with fresh gas. Thus, the turbulent substructure and magnetic field properties are imprinted during cloud formation. The formation of dense clouds from the multi-phase ISM, the onset of star formation, and the evolution of the molecular clouds under the impact of stellar feedback from newly born massive stars is studied in high-resolution simulations within the SILCC project. In this talk I will give an overview of the physics and chemistry involved in molecular cloud formation and evolution. After the onset of star formation, the latter is governed by stellar feedback from newly born massive stars. The detailed cloud substructure determines the clouds' vulnerability to stellar feedback processes, in particular to ionizing radiation. Moreover, the ionization state of the gas can be highly variable on scales of tens of parsec due to small-scale turbulent motions within the star-forming clouds, which shield and release the ionizing radiation. This leads to a flickering of the young HII regions on the scale of ~10 pc. On scales of several 100 pc and time scales of tens of Mega-years, the combined feedback from star clusters leads to a reduced star formation rate, such that long depletion time scales are observed.

Brown dwarfs populate the lower end of the IMF, and bridge the mass space between low-mass stars and planets. Due to their low mass, there is a strong debate about their formation mechanism(s). In order to confirm or discard those, we need to detect, and characterize, the different stages of brown dwarf evolution, which is no easy task. Ww have followed a systematic approach to the subject in our collaboration, from which we can extract some general lessons, and advice. Nonetheless, interesting and puzzling questions and challenges still remain and it is worth to keep them in mind. 

In the course of their accretion phase, massive (proto)stars impact their natal environment in a variety of feedback effects such as thermal heating, MHD-driven protostellar jets and outflows, radiation forces, and photoionization / HII regions. Here, I present our most recent simulation results in terms of the relative strength of the feedback components and the size of the reservoir from which the forming stars gain their masses. For the first time, these simulations include all of the feedback effects mentioned above which allows us to shed light on the physical reason for the upper mass limit of present-day stars. Furthermore, we predict the fragmentation of massive circumstellar accretion disks as a viable road to the formation of spectroscopic massive binaries and the recently observed strong accretion bursts in high-mass star forming regions.

To advertise our latest code development, I will also overview the most recent results obtained in a variety of other astrophysical research fields from the formation of embedded Super-Earth planets’ first atmospheres (Cimerman et al. 2017, MNRAS) to the formation of the progenitors of the first supermassive black holes in the early universe (Hirano et al. 2017, Science).

The complex nature of comets has earned them a spot among the most interesting objects in the Solar System. Comets are believed to still preserve information about the physical conditions in the protoplanetary disc. At the same time they also bear signatures of the epoch of planetary migration ~4 billion years ago, of the time spent in the outer solar system, as well as of their recent activity.

In the past three decades, a great progress in untangling the intricate history of comets has come from the in-situ studies during a series of space missions which culminated with the Rosetta mission between 2014 and 2016. However, with no plans for space missions to further comets in the next couple of decades, we have to rely more on telescope observations to reveal new details about the unanswered questions in cometary science.

In this talk, I will present results from our effort to study Jupiter-family comet nuclei and their source populations in the Centaur region and the Kuiper Belt. This work has demonstrated that ground photometric observations of the rotation and surface properties of comet nuclei can be key for understanding their evolution.

Massive star evolution is ruled by mass-loss. Through their stellar-winds, massive stars inject mechanical energy and radiation into their surroundings, influencing star formation and galaxy evolution. The generally accepted scenario foresees that very massive stars become Blue Supergiants, enter an instability phase during which they rapidly lose their H envelope through severe mass-loss, and form Wolf-Rayet stars. In this scenario, the unstable Luminous Blue Variable stars (LBVs) have a key role. Observations suggest that LBVs undergo short-duration eruptions, during which they release to the ISM a large fraction of their H-envelope with very high mass-loss rates. Among the many open issues, the mechanism that provokes the LBV instability and violent episodes of mass-loss is not clear, but it has been proposed that it is independent of metallicity, increasing the importance of LBVs in the early Universe. The physical conditions in their ejecta during the giant eruptions seem favourable for the formation and growth of dust. For these reasons LBVs are also candidate producers of dust in the early Universe. However, until recently little has been known about LBV nebulae in low metallicity environments. We carried out a pilot study of LBVs in the Magellanic Clouds with ALMA, VISIR and ATCA, focusing particularly on the mass-loss history and the dust content. I will show some results from our multiwavelength study, compare with Galactic objects, and discuss future perspectives offered by ALMA and the latest generations of instrumentation.

It has been over 44 years since the last extra-solar X-ray polarization observation was performed. As part of the NASA’s Small Explorer Program a new, exciting mission, will, for the first time, produce image-resolved polarimetry of astronomical sources. I am the Principal Investigator of this mission which includes a significant collaboration with the Italian Space Agency. I shall review the history of astrophysical X-ray polarimetry, discussing various experimental techniques and emphasizing the successful method of tracking the photoelectron in a low-Z gas developed in Italy that has allowed this experiment to proceed. After a discussion of the Observatory and its components, I shall present examples of the scientific advances that can be made by adding imaging polarimetry to the X-ray astronomer’s arsenal of tools for probing diverse questions such as: Was the black hole at the center of the Milky Way galaxy one million times more active a few hundred years ago? What is the spin the black holes in microquasars? Is there direct evidence for the effects of quantum electrodynamics in the strong magnetic fields in magnetars?

Magnitude, color, spectrum, and coordinates of light sources are the main parameters measured in most of the astronomical observations. However, the incoming light might show some degree of polarization. Polarimetric measurements allow to unveil important properties of the source and of the light path, otherwise hidden in common observations. We will discuss some aspects of polarization of light and its measurement with the Focal Reducer/low dispersion Spectrograph, FORS2, mounted on the VLT. In 2019 ESO is celebrating the 20th Anniversary of first light for FORS2.

High resolution ALMA observations recently provided strong hints for the presence of giant planets in the annular structures in young protoplanetary discs with separations up to 100 AU. I point out that these observations set unique "live" constraints on the process of gas accretion onto sub-Jovian planets that were not previously available. Using a population synthesis approach we compare the properties of the synthetic planets with the ALMA data at the same age. Applying the widely used gas accretion formulae leads to a deficit of sub-Jovian planets and an over-abundance of a few Jupiter mass planets compared to observations. We find that gas accretion onto planets needs to be suppressed by about an order of magnitude to match the observed planet mass function. This slower gas giant growth predicts that the planet mass should correlate with the age of the protoplanetary disc, albeit with a large scatter. This effect is not clearly present in the ALMA data. I show that the suspected ALMA planets are far more likely to form via gravitational fragmentation of massive protoplanetary discs followed by a partial mass loss. Detailed 3D simulations exemplifying this mode of planet formation will be presented.

Outflows of evolved stars drive the chemical evolution of galaxies in the local Universe. Population models dictate that low- to intermediate-mass asymptotic giant branch (AGB) stars dominate this process today, while in the early universe, massive stars and supernovae were likely the main contributors. However, many key issues regarding AGB mass loss remain unresolved. Thanks to Spitzer, a number of Local Group galaxies have been observed in detail, revealing the dust-production rates of all evolved stars, and hence the total dust injection rate for the galaxies. However, measuring the gas mass-loss rates outside our galaxy is prohibitive, making it unlikely that a large sample will be available in the foreseeable future, and systematic studies in the Milky Way remain conspicuously absent. The Nearby Evolved Stars Survey (NESS) aims to fill this gap, by targeting a volume-limited sample of roughly 400 sources within 2 kpc, enabling robust statistical studies of local evolved stars. We will derive the dust and gas return rates in the Solar Neighbourhood, and constrain the physics underlying these processes. I will present a detailed description of the project, including the motivation and strategy, and highlight some of our early results. I will also briefly introduce the tools we are developing that will, along with a catalogue containing all raw and reduced NESS data and a compilation of literature data, be released to the community to aid reproducibility.

The ESA cornerstone mission Gaia has been relentlessly scanning the full sky for nearly 5 years in order to create an unprecedented three-dimensional map of the Milky Way based on astrometric, photometric, and spectroscopic observations of more than 1.7 billion stars. The two first Gaia data releases (DR1, DR2) have already significantly impacted many areas of astronomy and astrophysics. Yet, the best is still to come with Gaia's mission lifetime having been extended to 6.5 years, and further extensions being likely. However, 10 months after DR2, several issues related to Gaia data have surfaced and are worth discussing.

This KES lecture aims to provide a digestible teaser of Gaia's enormous potential for stellar astrophysics and cosmology while addressing some lessons learned since DR2. To this end, the lecture is split into three main parts: i) a brief overview of the Gaia mission as the largest-ever homogeneous all-sky multi-instrument time-domain survey, ii) Gaia's variability processing with a focus on classical Cepheids and other pulsating stars, and iii) Gaia's impact on the distance scale and its relevance for resolving the Hubble tension. 

Extragalactic Planetary Nebulae (Pne) were mostly studied as secondary distance indicators in late and early-type galaxies, because of the cut-off of their luminosity function at bright magnitudes. With the use of 8 meter and custom built instruments of 4 meter telescopes, they become excellent spatial and kinematic tracers of their parent stellar populations.  In this talk, I will begin with the latest results on the kinematics within galaxies and give examples for the maximal  disk in NGC 628 and multiple disk components in M31. I will then move to the results from the extended Planetary Nebulae Spectrograph (e.PN.S) survey of a sample of local elliptical galaxies (ETGs). While ETGs are either fast and slow rotators at 1 R_e, their stellar halos traced by Pne show an increased  kinematical diversity. By using extended velocity fields out to 5.6 R_e on average, evidence is found for a kinematic transition between inner regions and halos, which depends on the stellar mass and correlates with the spatial transition from the ``in-situ'' to the ``ex-situ'' components  from cosmological simulations of galaxy formation.  I will then present the results based on the kinematics of the halos using Pne for the high mass end of the galaxy population: the cD galaxies in groups and clusters. I will describe how their stellar halos fade into the intra-group/intracluster light and the current measurements of their orbital anisotropy at 50-100 kpc. I will conclude with the constraints on the satellite progenitors of the stars in the outermost regions of these halos/ICL and with a forward look for the use of the ELT.

A recently proposed SN Ia channel is via the so-called sub-Chandrasekhar double-detonation scenario. In this scenario a white dwarf (WD) is orbited by a core Helium(He)-burning compact hot subdwarf star (sdB/sdO) in an ultra-compact orbit (Porb < 80 min). Due to the emission of gravitational waves, the binary is predicted to shrink until the hot subdwarf star fills its Roche lobe and starts mass transfer. He-rich material is then transferred to the C/O-WD companion which will lead to the accumulation of a He-layer on top of the WD. After accreting a small amount He-burning is predicted to be ignited in this shell. This in turn triggers the ignition of carbon in the core even if the WD-mass is significantly lower than the Chandrasekhar limit. However, the number of known systems is still limited. The Zwicky Transient Facility (ZTF) is a new time-domain survey with a 47 sqd. survey camera. I am scientific lead of a high-cadence survey in the Galactic Plane covering the full inner Plane visible from the northern hemisphere as part of ZTF. The goal of this survey is to uncover the population of short period variable stars in the Galaxy. In this talk I will present the discovery of several ultracompact white dwarf binaries with hot subdwarf companions as well as our strategy to find more systems using ZTF.

We investigate via numerical modeling the effects of two planets locked in resonance, and migrating outward, on the dust distribution of the natal circumstellar disk. We test whether the dust distribution exhibits peculiar features arising from the interplay among the gravitational perturbations of the planets in resonance, the evolution of the gas, and its influence on the dust grain dynamics. Models show that a common gap also forms in the dust component similarly to what a single, more massive planet would generate and that outward migration leads to a progressive widening of the dust gap and to a decoupling from the gas gap. As the system evolves, a significantly wider gap is observed in the dust distribution, which ceases to overlap with the gas gap in the inner disk regions.

Cool giant and supergiant stars are among the largest and most luminous stars in the Universe and, therefore, dominate the integrated light of their host galaxies. These stars were extensively studied during last few decades, however their relevant properties like photometric variability and mass loss are still poorly constrained. Understanding of these properties is crucial in the context of a broad range of astrophysical questions including chemical enrichment of the Universe, supernova progenitors, and the extragalactic distance scale.

Atmospheres of giant and supergiant stars are characterized by complex dynamics due to different interacting processes, such as convection, pulsation, formation of molecules and dust, and the development of mass loss. Dynamical processes in stellar atmospheres impact the formation of spectral lines producing their asymmetries and Doppler shifts. Thus, by studying the line-prole variations on spatial and temporal scales it is possible to reconstruct atmospheric motions in evolved stars. As will be shown in this thesis, a tomographic method is an ideal technique for this purpose. It is applied to pulsating Mira-type stars and RSG stars in order to better characterize their atmospheres and better understand respective mechanisms responsible for their photometric variability and mass loss.

The study of dwarf spheroidal galaxies (dSph) is of great importance to understand galaxy evolution at the low-mass end. In the Local Group (LG) the majority of them are found to be satellites of the Milky Way or M31. Although the closest ones have been studied in great detail, it is hard to constrain if their present-day observed properties are mainly caused by internal or environmental mechanisms.

To minimize environmental effects and gain an insight into their intrinsic properties, we are studying two isolated dSph galaxies in the LG, i.e. Cetus and Tucana, located far beyond the virial radius of the Milky Way and M31. These isolated dSphs, are also interesting because they break the morphology-density relation in the LG.

In this talk I will present results from a sizable spectroscopic sample of individual red giant branch stars taken with the VLT/FORS2 instrument in Cetus and Tucana dSphs. The spectra cover the near-IR CaII triplet wavelength region, from which we have obtained line-of-sight velocities and metallicities ([Fe/H]). The wide-area coverage of our data allowed us to obtain information on the large-scale kinematical and chemical properties of the considered galaxies, such as the possible presence of rotation, metallicity gradients, and multiple chemo-kinematic components. Results on the Cetus and Tucana dSphs place more stringent constraints on the formation mechanisms that led to their present-day morphology.

The Tully-Fisher (TF) relation is one of the tightest scaling laws in extra-galactic Astronomy, linking the visible mass of a galaxy to its outer rotation velocity. I will start with a brief historical overview of the TF relation and its application as a distance indicator. I will then focus on the physics behind the TF relation and its implications for dark matter and cosmology. In particular, the small scatter of the TF relation and the lack of residual correlations with galaxy radius lead to a number of non-trivial fine-tuning problems for current models of galaxy formation.

The circumgalactic medium (CGM; non-ISM gas within a galaxy virial radius) regulates the gas flows that shape the evolutionary paths of galaxies. It likely contains most of the metals lost in galaxy winds and enough material to sustain star-formation for billions of years.  Owing to the vastly improved capabilities in space-based UV spectroscopy with the installation of HST/COS, observations and simulations of the CGM have emerged as the new frontier of galaxy evolution studies. In this talk, I will describe observational constraints we have placed on the origin and fate of this material by studying the gas kinematics, metallicity and ionization state of gas 10 - 200 kpc from galaxies’ stars. I will conclude by introducing several exciting new techniques for resolving the gaseous structures in the CGM, and by posing unanswered questions about the CGM that will be addressed with future survey data and hydrodynamic simulations in a cosmological context.

The evolution of galaxies is largely shaped by the interplay between inflows, star formation and feedback processes. Heavy elements are key tracers of this cycle of baryons in and out of galaxies. In this talk I will use observations of nearby galaxies to explore the link between metal enrichment and their history of star formation. While this approach is typically employed in systems where individual stars can be resolved, I will discuss the challenges involved in measuring gas and stellar metallicities from integrated light. I will then explore what can be learnt from applying chemical evolution models to the overall galaxy population, as observed in large spectroscopic surveys.

Recent observations which resolved the mid-infrared (MIR) emission of nearby active galactic nuclei (AGN), revealed that their dust emission appears prominently extended in the polar direction, at odds with the expectations from the canonical dusty torus. This polar dust, tentatively associated with dusty winds driven by radiation pressure, is found to have a major contribution to the MIR flux from scales of a few to hundreds of parsecs. When facing a potential change of paradigm, case studies of objects with the best intrinsic resolution are essential. One such source with a clear detection of polar dust is a nearby, well-known AGN in the Circinus galaxy. Motivated by observations across a wide wavelength range and on different spatial scales, we proposed a phenomenological model consisting of a thin dusty disk and a large-scale polar outflow in the form of a hyperboloid shell. With detailed radiative transfer modeling, we demonstrated that such a model is able to explain the peculiar MIR morphology on large scales seen by VLT/VISIR and the interferometric data from VLTI/MIDI which probe the small scales. In contrast, while providing a good fit to the integrated MIR spectrum, the dusty torus model fails to reproduce the spatially resolved interferometric data. Our results call for caution when attributing dust emission of unresolved sources entirely to the torus and warrant further investigation of the MIR emission in the polar regions of AGN. We put forth the disc + wind model of Circinus as a prototype for the dust structure in the polar dust AGN population.

Exoplanetary discoveries in the past two decades have unveiled an astonishing diversity in the physical characteristics of exoplanetary systems, including their orbital properties, masses, radii, equilibrium temperatures, and stellar hosts. Exoplanets known today range from gas-giants to nearly Earth-size planets, and some even in the habitable zones of their host stars. Recent advances in exoplanet observations and theoretical methods are now leading to unprecedented constraints on the physicochemical properties of exoplanetary atmospheres, interiors, and their formation conditions.

I will discuss the latest developments and future prospects of this new era of exoplanetary characterization. In particular, I will present some of the latest constraints on atmospheric chemical compositions of exoplanets, made possible by state-of-the-art high-precision observations from space and ground, and their implications for atmospheric processes and formation conditions of exoplanets. The emerging framework for using atmospheric elemental abundance ratios for constraining +the origins and migration pathways of giant exoplanets will be discussed along with their implications for smaller rocky planets. A survey of theoretical and observational directions in the field will be presented along with several open questions on the horizon.

Galaxy clusters are dark-matter dominated systems enclosed in a volume that is a high-density microcosm of the rest of the universe. What is their true mass scale? What are the statistical properties of the represenatative population? How does their detectability depend on baryon physics? We have learnt a lot on these fundamental questions with our current projects, like XMM-Newton Cluster Outskirts Project (X-COP) and CLASH. More has to be understood and will be the focus of our next XMM-Newton Heritage Cluster Project that will pave the way in using the next generation of observatories, like XRISM eROSITA Euclid Athena, to construct a consistent picture of the formation and composition of galaxy clusters.

The unconscious brain processes are an important part of everyday life, but what effect do they have on our work, on the choices we make in the professions and our interplay with colleagues? I will present a few findings and discuss possible measures to adopt in order to make the workplace a fairer environment.

Transit spectroscopy is one of the main techniques for exoplanet atmosphere characterisation. Since a lunar eclipse has a similar geometry as exoplanet transit, it can be used to observe the Earth transiting the Sun. In this talk, I will present three lunar eclipses observations and three topics we learnt from these observations: Earth’s transmission spectrum, Rossiter-McLaughlin effect of the Earth transiting the Sun, stellar line’s center-to-limb variations during lunar eclipse. I will also present how we apply these knowledge to exoplanet atmosphere characterisations, especially the detection of sodium, hydrogen and helium in exoplanet atmospheres.

In collaboration with a renowned movie director Hiromitsu Kohsaka, who is specialised on full-dome movies (which you would watch in a full-dome projection of the planetarium), we have created the world’s first full-dome movie on the cosmic microwave background (CMB). In this 45-minutes movie, you will learn the history and physics of the CMB in an intuitive manner, with incredible computer graphics and beautiful original music. Actors and actresses are real people, but most of the other stuff are CGs.

While we cannot show this movie yet in the full-dome of ESO Supernova, I will show this on a flat screen. Enjoy! The trailer is available at: https://www.youtube.com/watch?v=CQbZi4wfoaw

Stellar astrophysics is undergoing a renaissance driven by new observational and theoretical capabilities. Wide-field time-domain surveys have uncovered new classes of stellar explosions, helping to understand how stars evolve and end their lives. Gravitational-wave astronomy is providing exciting insights in the properties of the final remnants of massive stars. Asteroseismology, the study of waves in stars, is also producing dramatic breakthroughs in stellar structure and evolution. Thanks to space astrometry, accurate distances are now available for an unprecedented number of galactic stars. From the theoretical standpoint, it is increasingly possible to study aspects of the three-dimensional structure of stars using targeted numerical simulations. These studies can then be used to develop more accurate models of these physics in one-dimensional stellar evolution codes.

I will review some of the most important results in stellar physics of the last few years, and highlight what are the most relevant puzzles that still need to be solved. I will put particular emphasis on the physics of massive stars, which are the progenitors of core-collapse supernovae, gamma-ray bursts and the massive compact remnants observed by LIGO.

Strong gravitational lenses with measured time delays between the multiple images can be used to determine the Hubble-Lemaître constant (H_0) that sets the expansion rate of the Universe. Measuring H_0 is crucial for inferring properties of dark energy, spatial curvature of the Universe and neutrino physics.  I will describe techniques for measuring H_0 from lensing with a realistic account of systematic uncertainties, and show the latest results from the H0LiCOW program.  I will show the bright prospects of gravitational lens time delays as an independent and competitive cosmological probe.

Stellar population synthesis models describing the energetic emission and stellar mass distribution of galaxies and star clusters are the essential analysis tool in astrophysics and cosmology. They are used to determine the physics of stellar systems (formation ages, star formation history and chemical composition) and dark matter fractions from data, to predict the spectral energy distribution of simulated galaxies, to trace cosmic time for constraining cosmological parameters , to predict the number, mass and location of stellar remnants giving origin to gravitational waves. Given their widespread use and core role, the accuracy of population synthesis models needs to be constantly improved for keeping pace with progress in instrumentation.

In this talk I shall appraise the progress made over the past two decades focusing on the most significant leaps - the treatment of late stages of stellar evolution and the inclusion of detailed chemistry - which starting from Munich have stimulated substantial work around the globe. I shall then introduce the next step in population model calculations, which will leverage the exploitation of current and future data and hopefully provide the solution to some current puzzles, including the universality of the Initial Mass Function.

As astronomy advances, the biggest gains are often found by combining different kinds of data in a single analysis, e.g. combinations of photometry, spectroscopy, imaging etc. However, such combinations pose a number of statistical challenges that inhibit simple analyses and require new tools to solve them. A key challenge is self-consistently combining data with radically different statistical and systematic uncertainties. I will highlight some recent advances in forward-modelling astronomical data that dramatically improve this situation, before presenting a new tool to fit general combinations of observations.

The assumption of a gas-to-dust mass ratio is a common approach to estimate the basic properties of molecular clouds, from (sub)mm continuum observations of the dust. In the Milky Way a single value is used at all galactocentric radii, independently of the observed metallicity gradients. Both models and extragalactic observations suggest that this quantity increases for decreasing metallicity Z, typical of the outer regions in disks, where fewer heavy elements are available to form dust grains. We investigate the variation of the gas-to-dust ratio as a function of galactocentric radius and metallicity, to allow a more accurate characterisation of the quantity of molecular gas across the galactic disk, as derived from observations of the dust.

Observations of the optically thin C18O (2-1) transition were obtained with the APEX telescope for a sample of 23 bright star-forming regions in the far outer Galaxy (Rgc>14 kpc). From the modelling of this line and of the spectral energy distribution of the selected clumps we compute the gas-to-dust ratio and compare it to that of well-studied sources from the ATLASGAL TOP100 sample in the inner galactic disk. The gas-to-dust ratio is found to increase with galactocentric radius, whereas the dust metallicity decreases, the most common situation also for external late-type galaxies, suggesting that grain growth dominates over destruction. The predicted gas-to-dust ratio is in excellent agreement with the estimates in Magellanic clouds, for the appropriate value of Z.

In experiments on Bell’s theorem the possibility is tested whether local realistic explanations of the correlations between entangled particles can explain the observed correlations. In the talk, I will first discuss possible loopholes in tests of Bell‘s Inequalities. I will then focus on the so-called freedom of choice loophole. This loophole is related to the demand that the measurements of correlations on two (or in principle more) entangled particles are free and independent. I will then in detail report on tests of Bell’s Inequality where cosmic sources are used to provide independent random input for the measurements t entangled photons. In the first experiment, stars within our Milky Way were used and in the second one, distant quasars. Another experiment has used choices of random numbers by humans. These numbers were directed to 13 experiments located globally at 12 different places. Finally, I will briefly mention the implementation of quantum cryptography between Europe and China using the Chinese quantum satellite Micius.

As a sequel to the Q&A session on the ELT telescope, the Project Scientists of the ELT instruments will provide an opportunity to ask question on those facilities.

A short introduction to METIS, HARMONI, MICADO+MAORY, MOSAIC and HIRES instruments will be given. Thereafter, the floor will be open for questions.

The discussion on the choice and performance of different gridding functions can be dated back to 1960s by Liz Waldram in Radio Astronomy group at Cavendish. In radio interferometry imaging process, the Fourier transform relation between the visibility data and the sky brightness distribution is usually implemented by Fast Fourier Transform (FFT), where a procedure called ‘gridding’ of convolving visibilities with a chosen gridding function is needed to assign visibility values into uniformly sampled grids. The spheroidal function has been widely used to suppress aliasing effects since early 1980s. We proposed "Least-misfit gridding function" under the criteria of minimising the difference between the DFT and FFT results. It is proved to have a better aliasing suppression performance than the spheroidal function on simulated dataset. It also minimises the DFT and FFT difference, outperforming the spheroidal function at least 10^2 times with the same gridding width and image cropping ratio. The least--misfit gridding function with a support width of 7 and an image cropping rate of 0.5 is recommended to be applied both into gridding and degridding process, so as to achieve the single precision in terms of the image misfit and visibility misfit respectively. Its application on our newly proposed wide-field imaging method can achieve the single and double precision with the gridding width equals to 7 and 14 respectively.

Circumstellar disks are fundamental for accretion and angular momentum distribution during the early phases of star formation. Class 0 objects are the youngest protostars and most embedded in their natal envelopes, and circumstellar disks can form even at this earliest stage of star formation, yet the envelopes enshrouding Class 0 and Class I protostars have made detection of young protostellar disks difficult.  Our high-resolution work with the VLA and ALMA  towards some of the youngest protostars addresses a variety of questions regarding the frequency, dust properties, kinematics, and chemistry at the earliest times. 

Just a decade ago it was believed that one could not form realistic dwarf or disk galaxies in cosmological simulations.  The past decade has seen immense progress, through both advances in resolution and development of physically motivated feedback models. Different simulators are generally now capable of forming realistic galaxies that match a wide variety of observed galaxy scaling relations, despite variations in adopted star formation and feedback recipes.

I will discuss the reasons for these successes, but also highlight a couple of areas where simulators are still facing challenges, e.g., in reproducing realistic galaxy bulges.  I will also show that the assumptions simulators have adopted in the classical dwarf regime will lead to widely varying predictions for the properties of ultra-faint dwarf galaxies. Finally, I will highlight future observations that have the potential to tightly constrain the physical conditions required for star formation at the earliest times.

Proper motions are crucial to fully understand the internal dynamics of globular clusters. To that end, the High-Resolution Space Telescope Proper Motion (HSTPROMO) collaboration has constructed large, high-quality proper-motion catalogues for 22 GCs in the Milky Way. For most clusters, these catalogues provide the most detailed kinematical data to date, with tremendous potential for improving our understanding of the dynamics and structure of individual clusters. Moreover, the size and diversity of the cluster sample, spanning a broad range of cluster properties (including environment and dynamical state), allows new studies of the GC populations as a whole. I will discuss some of our exciting recent results including: the first 2D kinematical maps for a large sample of GCs; the first directly-measured radial anisotropy profiles for a large sample of GCs; the first dynamical distance and mass-to-light ratio estimates for a large sample of GCs; and the first dynamically-determined masses for hundreds of blue-straggler stars across a large GC sample.

I will give a short introduction to galaxy formation simulations, including their overall purpose, motivation, and utility for studying various questions within the context of galaxy formation and evolution. First, I will compare the different types, approaches, and computational methods. I will discuss the common physical ingredients -- which physical processes are typically included in current simulations, 'subgrid' models, and future directions in this front. With reference to Illustris and IllustrisTNG in particular, I will discuss model calibration (tuning), and typical 'caveats' to the use of these types of simulations.

In the second half, we will get practical and discuss the simulation outputs -- what kind of data exists, and how it can be used. I will go quickly through how to use the IllustrisTNG public data release (online), including its documentation, getting started tutorials, and examples for data analysis. We can discuss the creation of synthetic (mock) observations, how to compare the simulations to any type of observation that people may have, and other topics of interest.

I will talk about the discovery and confirmation of Proxima b, the current efforts to investigate the presence of other planets orbiting around this star, and the characteristics of Proxima Centauri that act as noise and might hide the imprint of a further planets. I will also outline some of the current ideas to disentangle planetary signal from stellar noise for M Dwarfs and Solar-like stars.

Feeding and feedback tied to supermassive black holes (SMBHs) play central role in the cosmic evolution of galaxies, groups, and clusters of galaxies. The self-regulated active galactic nucleus (AGN) cycle is matter of intense debate. I review key results of our numerical campaign to unveil how SMBHs are tightly coupled to the multiphase gaseous halos, linking the inner gravitational radius to the large Mpc scale and vice versa. Massively parallel magnetohydrodynamic simulations show the turbulent plasma halo radiatively cools via a top-down multiphase condensation rain of warm filaments and molecular clouds. The multiphase precipitation inherits the hot halo kinematics and thermodynamics, ultimately establishing a 'cosmic weather'. In the nuclear region, the recurrent collisions between the clouds and filaments promote angular momentum cancellation and boost the SMBH accretion rate through a mechanism known as Chaotic Cold Accretion (CCA). The CCA rapid variability triggers powerful AGN outflows, which quench the macro cooling flow and star formation, while preserving the atmospheres of galaxies, groups, and clusters in global thermal equilibrium throughout cosmic time. I highlight the key imprints of AGN feedback and feeding, such as bubbles, shocks, turbulence, and condensed structures, with a critical eye toward observational concordance, including the X-ray plasma, optical filaments, and radio molecular clouds.