Semi-analytic models (SAM) of galaxy formation are a frequently used tool to model the physics acting on baryons in and around galaxies. Current models have become very successful in reproducing local galaxy properties such as stellar masses, sizes, gas reservoirs, star-formation rates, stellar metallicities, and black hole masses.

In this informal discussion I will present the schematics of SAMs and discuss what physical processes are typically included and how. I will highlight a few of them, revealing why we think they work or what their problems are. Last, I will discuss some of the recent successes and failures of SAMs and discuss what steps are to be taken next.

We present some of the highlights from a workshop held in Toulouse a couple of weeks ago in the framework of the MaTYSSE project. MaTYSSE aims to map the large scale magnetic fields of low mass pre-main sequence stars which have mostly dissipated their accretion disc (weak-line T Tauri stars) in order to investigate how they differ from those that are still accreting from their circumstellar discs (classical T Tauri stars), as well as how they differ from their main-sequence counterparts. This 3-day workshop brought together theorists and observers working on stellar magnetic fields, accretion, discs and planets. We will give an overview of the results discussed as well as new/planned instrumentation that will further work in this area (e.g., CARMENES, CRIRES+, SPIRou).

The Open Clusters of the Milky Way are very informative in many aspects, being testbed of stellar evolution models and tracers of the chemical evolution of our Galaxy. During the discussion I will briefly overview the characteristics of these objects and focus on the details they provide about chemical evolution of the Galaxy and (extra) mixing in steller interiors. Which constraints can we get from OCs? I will discuss this from an observer's point of view.

As our Sun rotates, stars rotate too, thus producing dynamo processes and magnetic activity that occur in their interior, on their surface, and along their surrounding medium. The high-accuracy data of the CoRoT and Kepler space telescopes have allowed us to measure directly the rotation periods for tens of thousands of stars, as well as the magnetic activity cycles (similar to 11-yr solar cycle) for several of them. These unique and direct measurements have helped us to better understand, for example, how the spin affect the stellar evolution and how similarly (or differently) it occurs in our Sun in comparison to Sun-like stars.

Irradiation effects in secondary stars of close binary systems are crucial for a reliable determination of system parameters and understanding the close binary evolution. They affect the stellar structure of the irradiated star and are reflected in the appearance of characteristic features in the spectroscopic and photometric data of these systems. We aim to study the light originating from the irradiated side of the low mass component of close binary eclipsing system comprising a hot subdwarf primary and a low mass companion, in order to precisely interpret their high precision photometric and spectroscopic data, and accurately determine their system and surface parameters. We re-analyse the archival high-resolution time-resolved VLT/UVES spectra of AADor system where irradiation features have already been detected. After removing the predominant contribution of the hot subdwarf primary, the residual spectra reveal more than 100 emission lines from the heated side of the secondary that show maximum intensity close to the phases around secondary eclipse. We analyse the residual spectrum in order to model the irradiation of the low mass secondary. We perform a detailed analysis of 22 narrow emission lines of the irradiated secondary, mainly of Oii, with a few significant Cii lines. Their phase profiles constrain the emission region of the heated side to a radius ≥ 95 % of the radius of the secondary, while the shape of their velocity profiles reveals two distinct asymmetry features one at the quadrature and the other at the secondary eclipse. In addition, we identify weaker emission signatures originating from more than 70 lines including lines from He i, Nii, Si iii, Ca ii and Mg ii. From the emission lines of the heated side of the secondary star we determine the radial velocity semi-amplitude of the center-of-light and correct it to the centre-of-mass of the secondary which in turn gives accurate masses of both components of the AADor system. The resulting masses M1 = 0.46 ± 0.01M⊙ and M2 = 0.079 ± 0.002M⊙ are in perfect accordance with those of a canonical hot subdwarf primary and a low mass just at the substellar limit for the companion. We also compute a first generation atmosphere model of the low mass secondary, which includes irradiation effects and matches the observed spectrum well. We find an indication of an extended atmosphere of the irradiated secondary star.

A planetary nebula (PN) is known as the ionized envelope surrounding a white dwarf , the final fate of low- and intermediate-mass stars. This stellar phase is also important for its contribution to the interstellar medium, when PNe drive out s-process elements, molecules as well as different dust species, the building blocks of life. One of the most discussed topics in the PNe research field is their huge variety of morphologies and how the more complex forms are sculpted. The theoretical models predict the existence of collimating agents such as disks (steady and/or rotating), jets, and binary systems to sculpt these perplexing morphologies. However, the observations able to detect these shaping engines are often quite difficult to accomplish. Furthermore, the transition to PN hides the clues of this process, when the AGB, post-AGBs, proto-PN, and the circumstellar environments of young PNe are compact and embedded in dust. I will present some results implementing observational techniques and different analysis in a effort to inspect and resolve these structures in infrared wavelengths and using two VLT instruments: CRIRES (near-IR) and VISIR (mid-IR).

I discuss the discovery with an amateur telescope of DGSAT I, an ultra-diffuse, quenched galaxy located ~10 degrees in projection from the Andromeda galaxy M31. Initially interpreted as a low-surface brightness dwarf spheroidal galaxy in the Local volume, radial velocity measurement suggests that this system is an ultra-diffuse galaxy associated to the Piscis-Perseus  supercluster and similar to those recently discovered in the Coma cluster. Its origin of this ultra-diffuse galaxies (with a size comparable to the Milky Way but with only ~1% of the stellar content of our Galaxy) is still a mystery for modern galaxy scenarios.

The surface rotation rates of young solar-type stars decrease rapidly with age from the end of the pre-main sequence through the early main sequence. This suggests that there is also an important change in the dynamos operating in these stars, which should be observable in their surface magnetic fields. Here we present early results in a study aimed at observing the evolution of these magnetic fields through this critical time period. We are observing stars in open clusters and stellar associations to provide precise ages, and using Zeeman Doppler Imaging to characterize their complex magnetic fields. Results for 15 stars, in five associations between 20 Myr and 250 Myr old, are presented. We find a trend towards weaker magnetic fields with age, and to weaker fields with Rossby number. Comparing to previous results for T Tauri stars, we see a strong change in magnetic strength and geometry with the development of a radiative core. Observations are in progress to extend the sample to a wider range of ages and rotation periods.

Disk dispersion timescales are an important calibrator for models of disk evolution and planet formation. By studying disks in different evolutionary stages within and between clusters of different ages, it is possible to estimate disk clearing times and lifetimes. From these studies it now becomes clear that disk lifetimes are a function of stellar mass, where disks around lower mass stars survive longer. How these parameters change for the lowest mass objects is still unclear.

I will present an ongoing project in which we observe 32 disks around stars that cross the very low mass stars to brown dwarf boundary (spctral types between ~ M3 and M8) in two star formation regions at ~1 and ~10 Myr: Taurus and Upper Sco. We characterize the stellar and disk parameters of our targets using a multi wavelength dataset including ALMA, Herschel and XSHOOTER observations, with the (perhaps somewhat ambitious) aim of finding out what makes these disks live longer. In my talk I will give a special focus to the XSHOOTER dataset.

This informal discussion is a double feature given by astrophysicist Aoife Boyle (Queen’s University Belfast) and computer scientist Vytautas Jančauskas (Vilnius University). Both of them work on the supernova radiative transfer code TARDIS and are visiting for a week.

Vytautas will introduce the concepts of multi-objective optimization (solving problems that have several, possibly contradictory criteria) and its importance in real-life scenarios. Discuss the concepts of Pareto dominance, non-dominated sets and traditional approaches to multi-objective problems. Limitations of weighted-aggregate approaches.

Aoife will talk about her work on the state of helium in type Ia supernovae, how this state is altered by non-thermal effects, and how the inclusion of these effects in simulations changes the predicted spectra for certain type Ia supernova models. She will also discuss her work on the plasma section of the TARDIS code, which has involved simplification of the overall structure and the addition of new modules for calculating the state of helium.

In this talk, I review the main ingredients of the dynamical evolution of young star clusters, focusing on evaporation, core collapse, mass segregation and equipartition. Whether (young) star clusters actually reach equipartition is still an open question, and dynamical simulations show a very complex picture. Finally, I discuss how stellar evolution can affect the most important dynamical processes that occur in star clusters, including the collapse of the core. The Gamma Velorum cluster is an intriguing example of the impact of stellar evolution, stellar dynamics and gas physics onto the early evolution of the young star clusters in the Milky Way.

I discuss the star formation history of the Milky Way, how its constituent components grew their stellar masses, with the context of what we know about distant galaxies.  The evolutionary history of the MW provides interesting insights into why galaxies are dynamically hot in the early universe, what may "quench" galaxies, and how thin and thick disks grow.

After introducing the LMC and its unique peculiarities, I will show you how we can use chemical abundances to constrain the chemical evolution of the LMC.

Radial velocity and transit surveys have revealed a large and diverse population of exoplanets in our Galaxy. To truly understand them we need to obtain spectra of their atmospheres in order to probe their compositions and determine the dominant physical processes. Transiting planets allow such measurements via transmission spectroscopy, which has been a very active field of research over the last decade. I will introduce this technique, and present the first complete UV to NIR transmission spectrum of a hot Jupiter.

High mass star clusters represent the peaks of Galactic density distributions,
forming in massive clouds that dominate the overall star formation budget of
Milky Way-like galaxies.  These clusters are important places to study the
initial mass function because they form stars over a very short period.  The
rapid formation also means that feedback has little effect on the clusters
themselves, but a large effect on the surroundings. I will discuss observations
of the density structure during the early stages of formation of these massive
clusters and the tools used to measure the density.  I will also describe what
we hope to learn with ongoing and future observations.

I will present the preliminary results of a study of the microquasar GRO J1655-40 that hint at the presence of AGN-like Compton-thick winds. These winds are likely responsible for an optical and infrared thermal excess, and may be launched during an episode of super-Eddington accretion. I will first give a general introduction to relevant microquasar properties, before detailing the study itself.

Studies of distant Type Ia supernovae were responsible for the discovery of the accelerating Universe and the presence of dark energy. I will give an overview of the current status of Type Ia supernova cosmology including the latest constraints from dedicated surveys. I will discuss how Type Ia supernovae are 'standardised', what are the main limitations, and what future measurements will tell us about the properties of dark energy.

Although the star formation rate and black hole activity in the central parsecs of our Galaxy are orders of magnitude below levels observed in the most extreme environments in the universe - in ULIRGS and quasars - the center of our Galaxy is still the most extreme environment for molecular gas which can be imaged on sub-parsec scales. The ability to  resolve individual molecular clouds, clumps, and cores in this region makes it an ideal environment to investigate how the processes which contribute to the mixing, heating, and unique chemistry of gas in this region affect the star formation, and whether they can be scaled up to more extreme environments. I will highlight recent work which focuses on determining the densities and temperatures of gas in the Galactic center on parsec to sub-parsec scales using the GBT, VLA, and APEX. I will discuss how this work has contributed to our understanding of the Galactic center environment, and the unknowns that remain. Finally, I will close the discussion with some potential pitfalls in measuring densities and temperatures in our own and other galaxies.

SN 1987A was born special and remained unique until today. No other supernova has given us the chance to learn and understand about these explosions than SN 1987A. It has shown everything: neutrinos, shock breakout, cooling, recombination, radioactivity, a circumstellar ring system first ionised by a flash and later shocked by the supernova blast wave. Today we observe the inner asymmetric ejecta heated by radioactivity and fried by X-rays from the ring, the reverse shock within the ejecta, the forward shock within the ring, the shocked ring and the still recombining ring. Current research focusses on the search of the neutron star, the geometry of the explosion, the destruction of the ring, and first signs of emission from outside the ring. SN 1987A is as exciting as ever!

In this discussion session, I will present my recent work on studying the cosmic
star-formation activity using stacking analysis. I will briefly introduce the stacking
method used in this work, along with some other popular methods found in the
literature, and discuss the results from exploring the star-formation rate (SFR)
and specific SFR as a function of mass and redshift from z~4 to the present epoch.

In this informal discussion I would like to report on our most recent discovery of the 
fastest unbound star in the Galaxy and how we explain the acceleration of this object 
by a thermonuclear supernova. Furthermore, I would like to share some of my 
experience publishing in an high-impact journal for the first time. It was an 
interesting, but cumbersome exercise.

The Archive Science Group will give an overview of the products releases published through the ESO Science Archive Facility. It will be followed by short demos on queries and retrievals of catalogs imaging products and internal data products.

Detailed simulations of supernova explosions are essential for testing theoretical progenitor and explosion physics scenarios.  Exploring the full parameter space of models can be challenging, due to the large number of degrees of freedom and the complexity of the phenomena being simulated.  The bolometric light curve, while demanding to measure from an observer's point of view, can be predicted semi-analytically and is sensitive to global parameters of the event such as the progenitor mass, kinetic energy, and distribution of radioactive elements in the ejecta.  I will describe an analysis framework which uses at its core a parametrized, semi-analytic description of the supernova ejecta and the bolometric light curve, treating the ensemble behavior of contemporary classes of numerical models as priors for Bayesian inference on the global parameters.  The method has been shown to work surprisingly well for type Ia supernovae, yielding ejected masses with ~10% accuracy and enabling the measurement of the detailed mass distribution of type Ia supernova progenitors (putting strong new constraints on viable explosion models).  With some modification, a similar approach could be used to test classes of models for massive star explosions and other types of transients.

The speakers will give a report on the 2014 ALMA Science Conference, focusing this week on Extragalactic Astronomy.

Nowadays, the development of the observational instruments is so high that became very sensitive
to the details of stellar surface. I will present how 3D simulations of stellar convection, across the
Hertzsprung-Russel diagram, are used for the interpretation of stellar surfaces images, fundamental
parameters, stellar variability and planet detection.

Nowadays, the development of the observational instruments is so high that became very sensitive
to the details of stellar surface. I will present how 3D simulations of stellar convection, across the
Hertzsprung-Russel diagram, are used for the interpretation of stellar surfaces images, fundamental
parameters, stellar variability and planet detection.