Seminars and Colloquia at ESO Santiago

The deeply embedded phase of star formation is particularly

interesting because the star itself is still being built up and the

disk is still being formed. Ultimately, it is the physical and

chemical structure of the disk and infalling envelope that determine

the system's potential for planet formation and its building blocks of

life.  Since the protostar is obscured by hundreds of magnitudes of

extinction from the surrounding dense cloud, it can only be observed

at long wavelengths as provided by ALMA.

The ALMA Protostellar Interferometric Line Survey (PILS, PI

J. Jorgensen) consists of an unbiased line survey of the most

line-rich low-mass system, the protostellar binary IRAS 16293-2422 in

Ophiuchus (27 L_Sun, d=125 pc). It covers the full Band 7 spectral

window from 329 to 363 GHz with a spectral resolution of 0.2 km/s and

imaging at 0.5" angular resolution (60 AU). Complementary data in

selected settings in Band 3, 6 and 9 are also available, down to 0.2"

(15 AU radius). Thus, the chemistry and physics can now be studied in

young solar system analogs on scales corresponding to the orbit of

Uranus. Initial PILS results on the chemical inventory near source B

will be presented, illustrating the wide range of complex organic

molecules and deuterated forms that have been found. See

http://youngstars.nbi.dk/PILS/ for list of publications.

M87, which is the massive elliptical galaxy at the center

of the Virgo Cluster, is a promising candidate to reveal

the shadow image of its Supermassive Black Hole (SMBH).

Greenland Telescope (GLT) project is aiming to image the SMBH

shadow using submillimeter VLBI technique together with other

submillimeter telescopes, such as the Phased ALMA in Chile

and JCMT/SMA in Hawaii.  The big triangle formed by GLT-ALMA-

JCMT/SMA provides 20 micro-arcsecond resolutions at 350 GHz

towards M87, whose shadow size are expected to be about 40

micro-arcsecond.  LMT in Mexico is located almost at the

center of the big triangle, and other Event Horizon Telescope

(EHT) antennas would provide the high quality image of the

shadow.  Main components of the GLT antenna are already

shipped to Thule, Greenland, and currently we are reassembling.

We are planning to make a few initial VLBI observations in

2017/2018.  We will also arrange the infrastructures of the

final destination, the summit of Greenland.  In this

presentation, I will report the current status of the project.

According to the Lambda-CDM cosmology, galaxies are build-up
hierarchically, through the progressive accretion of smaller satellites
systems. Sagittarius (Sgr) tidal stream is the most definite example of
Milky Way's satellite accretion in action. In principle, the orbit of Sgr
allows to measure the mass and the shape of the dark matter halo of our
Milky Way. Nonetheless, the Sgr stream exhibits bifurcations and
substructure difficult to reconstruct with models. The stream has been
mapped all over the sky, but gaps have remained until now: one of them, at
least 100 degrees wide in the immediate neighborhood of the parent. In
this talk, I will present the tracing of the Sgr trailing arm in this
unstudied innermost region near the parent using the VST ATLAS data. We
used photometrically selected Sub-Giant Branch stars to reveal a complex
debris morphology of the trailing arm and detected at least two clear
peaks in the SGB distance modulus distribution. One of the peaks is
consistent with the southern continuation of the trailing arm, connecting
the previous detections with the current position of the Sg remnant. The
second detection is unexpected since no counterpart exists in simulations
of the Sgr disruption. These new detections ought to provide a good
leverage in constraining the properties of the gravitational potential of
the Galaxy.

Debris disks are second generation dust disks around roughly 10 Myr or older stars, which have lost their original
gas. They also have a total disk luminosity which is at least a 100 times fainter than their parent star.
Since planets are very hard to detect around young systems, because of the scarcity of the systems and the low
percentage yield of traditional planet detection techniques, we know very little about how planetary systems form.
The plethora of observed debris disk features, like rings, spirals, warps hold the promise to reveal the configurations
of hidden planetary systems in formation, through the physics of gravitational interactions between large bodies and dust. Here, I review the high resolution imaging observations of debris disks and pose questions about a particularly interesting and increasingly common type of debris disk: the narrow ring systems. Can such systems remain as narrow rings without the need for shepherding planets? If they can, what conditions are necessary for them to arise? What fraction of debris disks and at what ages should be such rings be narrow, according to model predictions? If narrow systems cannot remain narrow without planets, what sort of planets are necessary for their maintenance?

I will present a spectroscopic and photometric analysis of type II supernovae (SN II) obtained by the Carnegie Supernova Project (CSP), plus previous campaigns between 1986 and 2009. In total 123 supernovae with ~900 optical spectra and a good photometric coverage (optical and infrared) were followed. Spectral parameters were analysed and correlated with photometric properties. During this talk I will discuss possible explanations of these results in terms of physical properties of SNe II, speculating that the most likely parameters which influence in the spectral diversity are the mass and density profile of the hydrogen envelope, together with additional emission components due to circumstellar interaction. I will also discuss possible relations between the observed parameters with the physical properties of the progenitor and explosion . Linking these pre-SN properties to initial progenitor properties can provide insights into the diversity of SNe II progenitors.

The extraction of exoplanet spectra is currently a major interest in the field of exoplanet imaging, mostly with the new generation of high-contrast instruments equipped with an IFU, such as the VLT/SPHERE-IFS. MEDUSAE is an algorithm dedicated to process coronagraphic multispectral images from ground-based telescopes. This innovative method exploits the spectral redundancy to jointly estimate the instrumental aberrations and the astrophysical scene thanks to an inverse problem approach. During this talk I will describe the strategy followed by the algorithm and the results obtained from its application on simulated data. I will then present the perspectives toward its application on real on-sky images.

I will summarize various independent observational evidences about the
presence of two different stellar components in the galactic bulge. The
two differ by mean metallicity, alpha element ratios, kinematics and
spatial distribution. They might have had a very different origin, or,
as recently proposed, they might be the result of a secular process
that funneled to the Galaxy central region stars whose properties
were different, as time went by.
In any case, these recent observational constraints must be met by
any bulge formation model.

Sulphur (S) and Zinc (Zn) are rarely targeted by stellar abundance studies: they are
difficult to measure (S in particular) and are considered to trace
other alpha elements (for S) and iron (for Zn) in their abundance evolution.
However, they bear great importance in Interstellar Medium studies because they
are very volatile, and remain in the gas phase (where they can be measured)
rather than forming dust. For all these reasons, they are the proxies of
choice for alpha elements and iron in studying the abundances of Damped-Lyman-Alpha
systems: it is thus important to investigate whether they do in fact behave as
expected in local stars, where Fe and other alpha elements can be handily measured.

The Gaia-ESO (GES) internal data release 4 allows us to measure S abundances in ~1300
stars, and Zn in ~1700, Comprising local thin/thick disk dwarfs, and giants
mostly in globular and open clusters over a variety of galactocentric radii.
Sulphur appears indeed to behave as an alpha element (albeit with surprising
results in 47 Tucanae), but Zn has a complex behavior, following Fe only partly,
with signs of a more complex nucleosynthetic history than previously thought.

Luminous Infrared Galaxies (LIRGs), with IR luminosities > 10^11 Lsun, represent a key stage in galaxy formation and evolution. They are the most important population of galaxies at redshifts z > 1, accounting for more than 50% of all star formation produced in the Universe at those epochs. Studying their local counterparts is therefore fundamental for our understanding of the physical properties and phases of the inter-stellar medium (ISM) in active galaxies, near and far. At low redshift, LIRGs range from what is called the main-sequence (MS) of star-forming galaxies to out-of-MS systems. Their bolometric luminosity is largely dominated by massive, compact bursts of star formation, although they show a wide range of contributions from active galactic nuclei (AGN). Nearby LIRGs are a mixture of isolated disk galaxies, interacting systems, and advanced mergers, covering the entire range of interaction stages. Here I will present results regarding the gas and dust properties of the largest, most complete sample of LIRGs in the local Universe: The Great Observatories All-sky LIRG Survey (GOALS). The full coverage of Spitzer and Herschel imaging and spectroscopic observations allow us to study their ISM and investigate differences among sources as a function of AGN activity, merger stage, dust temperature, and compactness of the starburst – parameters that are thought to control the life-cycle of galaxies moving in and out of the MS, locally and at high-z. Finally, if time permits, I will discuss recent results based on ALMA observations of the ionized gas in W2246-0526, a high redshift (z=4.6) Hot, Dust Obscured Galaxy that is also the most luminous galaxy in the Universe known to date.

The discovery of more than 3500 extrasolar planets has given us the opportunity to thoroughly
study their host stars. The determination of chemical abundances provide us with unique
information not only about the stellar atmospheres but also about the processes that take place
inside the stars and how they have been formed. The first difference we came across between
stars with and without planets was that the former are on average more metallic but other trends
have been reported during these years. I will make a short review about these studies and focus
more specifically on light elements and the information they can give us about the formation
of planetary systems and the engulfment of close-in planets by red giants.

The detection of reflected light from exoplanets is a daunting task, pushing
current observing facilities to their limits. The advent of 30m class
telescopes will get us past these boundaries, enabling us not only to detect
reflected light from exoplanets, but recover the color dependence of those planets
albedo function. This quantity is paramount towards the understanding of exoplanet
atmospheres as it is highly dependent on the constituents of a planet's atmosphere
and is a direct measure on how these reflect the incident light under a given
conditions of temperature and pressure.

In this talk I will show how the Cross Correlation Technique presented in Martins et al 2015
can be used to recover recover the color dependence of the albedo function from exoplanets
with next generation observing facilities. I will present some results
on the recovery of the color dependence of the albedo function from selected known planets
from simulated observations with ESPRESSO@VLT and HIRES@E-ELT.

About a dozen substellar companions orbiting young stellar objects at several hundred au have been identified in the last decade. These objects are interesting because we don’t know how they formed and because their large separation from the host star offer the potential to study the atmospheres of young giant planets and brown dwarfs. We will present X-shooter spectroscopy of Sr 12 C, a brown dwarf orbiting SR 12 at an orbital separation of 1045 au. We determine the spectral type, gravity, and temperature using model and observed templates of brown dwarf spectra and test for accretion using several accretion tracers. The X-shooter spectrum provides clear evidence for accretion at a relatively low rate.I will discuss the implications of this result in the context of formation scenarios for substellar companions at large orbital separations.

Current galaxy evolution ideas tie star formation (SF) and black hole (BH) activity through 1) merger driven inflow of gas to the centers of colliding galaxies, and/or 2) secular evolution fed by cold gas flow onto young galaxies. In these scenarios, a common reservoir of cold gas is available for both SF and BH accretion but the different physical scales associated with the two processes might imply different time scales. Clear, quantifiable evidence for this stellar and BH growth is still missing, making difficult to asses the impact of BH activity in their host galaxies. To remedy this, we are carrying out systematic studies of well defined populations of high-z quasars to determine the instantaneous growth rate of MBH and M∗, the role of mergers in triggering SF activity for different redshift bins. In this talk I will present space and ground-based observations (including ALMA), which are slowly helping to build a picture of the BH activity and their host-galaxies at high-z.

Whereas the so-called “chemically peculiar stars” seemed to be very exotic objects, the other main-sequence stars, referred to as “normal”, were thought to be more simple and well known. Recent studies show however that all these objects hide some surprises. Chemical segregation occurs inside most main sequence stars leading to element accumulation in some internal layers, which may have important consequences for the opacities and lead to specific instabilities. I will review the recent works on this subject and discuss the consequences in connection with stellar observations

(a) Frequency modulation due to orbital motion

(b) Phase modulation due to orbital motion

(c) A planet in an 840-d orbit around an A star found from phasemodulation

(a) Efects of rotation on stellar oscillations

(b) Internal rotation becomes observational astronomy

(c) Determination of three-dimensional spin-orbit angle of exoplane-tary systems

(d) Angular momentum transfer by waves

Supermassive black hole growth, nuclear activity, and galaxy evolution have been found to be closely related. To understand the role of BH  activity in galaxy evolution, how relevant is feedback and how it works, it is fundamental to combine statistical studies of complete and unbiased sample of AGN with detailed multi-wavelength analyses of well selected objects undergoing the feedback dominated phase of AGN-galaxy coevolution. In this context, I will present some of the observational results obtained in the last year by our team aimed at understanding the possible effects of nuclear activity and AGN-driven winds in regulating host galaxy growth.

(a) Observational aspects of stellar oscillations

(b) Theory of stellar oscillations

(c) Excitation and damping of oscillations

(d) Super-Nyquist asteroseismology

Red supergiants (RSG) stars have been confirmed as the progenitor stars of the majority of hydrogen-rich type II supernovae (SNe II). However, while RSGs are observed with masses higher than 25Msun, detections of SNe II progenitors >18Msun have remained elusive. RSGs are also expected to form at all metallicities, but given the historical galaxy-targeted nature of past SN surveys, discoveries of explosions from such low-abundance progenitors are also scarce. Here, we report observations of the SN II CSS140925:223344-062208, aka CSP14acu, for which we infer a progenitor metallicity of ~0.1Zsun and a Zero Age Main-Sequence (ZAMS) mass of >20Msun. CSP14acu displays a relatively normal light-curve morphology, together with the typical Balmer lines usually observed in SNe II, implying a RSG progenitor. However, there is a clear lack of strong spectral lines originating from heavier elements such as iron. Comparison to spectral models confirm a progenitor metallicity of ∼0.1Zsun or lower. This is consistent with observations of the host galaxy that constrainits absolute magnitude to be the lowest of any SN II host to-date. At late phases CSP14acu also shows unique features among SNe II. [OI] is much stronger with respect to H-alpha and [CaII]  than all known SNe II. Nebular hydrogen emission is also broader implying higher velocities for the outer core material. CSP14acu is thus constrained to have a helium core mass produced by the explosion of an >20msun initial mass progenitor. Why such a massive progenitor should also be related to such a low progenitor metallicity is currently unknown.

I will present the results of our search for extragalactic Radio Recombination Lines (RRLs) from M82 using LOw Frequency ARray (LOFAR) observations. The goal of our search is to study the cold gas component of the interstellar medium of this object, for which low-frequency radio recombination lines can provide a unique and sensitive probe.

Following the detection achieved in the ~48-64 MHz frequency range using the LOFAR Low Band Antennae, I will present our results within the High Band Antennae frequencies (~152-174 MHz). To constrain the properties of the gas, ongoing complementary efforts focus in combining these measurements with VLA P-band observations and new modeling of low frequency RRLs.

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.

The two main models for high-mass star formation, ‘core accretion' and ‘competitive accretion,' predict different internal structures for cluster forming clumps only in the very earliest stages. The best way to distinguish between these models therefore is to identify cold, cluster-forming clumps and measure their internal structure directly.

Observations of Galactic plane surveys have allowed us to determine the physical global properties of proto-cluster candidates in the Galaxy. Using data from ATLASGAL and Hi-Gal dust continuum surveys and the MALT90 molecular line survey, we have compiled information about the mass, density, luminosity and temperature of more than 1000 clumps in the Galaxy, identifying several clumps that satisfy all the requirements for cluster-forming clumps in very early stages of evolution and making possible the selection of the best candidates of clumps in the verge of star formation, for follow up observation of their small-scale structure with ALMA.

Here we present the properties derived for star forming clumps in the Galaxy and our ALMA observations of the continuum, and molecular line toward some of these clumps, which have allow us to measure its internal structure and assess whether the cores are gravitationally bound and collapsing.

The far-infrared Herschel Space Observatory has opened our eyes to the cold dusty Universe. Far-IR wavelengths provide arguably the best tracers for star-formation in active galactic nuclei (AGN), since luminous nuclear activity is rather inefficient at keeping dust cold. I will report on studies that bring together the very best modern multi-wavelength survey datasets, from the X-rays to the optical to the far-IR, aimed towards developing a coherent view of the growth of supermassive black holes (in AGN) and the growth of stellar content in galaxies (through star-formation). These studies build on the newest advances in our knowledge of galaxy evolution across most of the Universe's history. I will demonstrate that a positive relationship between star-formation and AGN activity is now clearly seen to z > 2. However, the nature of this relationship supports weak or stochastic co-evolution, driven more by the smooth increase of gas content in normal galaxies over time rather than a dominant role of short, intense episodes, such as star-bursts or mergers. This has important implications for the connections between galaxies and the black holes that reside at their hearts.

I will discuss the results of re-measuring the mass-metallicity relation (MZR) of local star forming galaxies using IZI, a recently developed Bayesian code that measures the physical properties of ionized nebulae using photo-ionization models. I will make the argument for the existence of a characteristic transition mass scale in the MZR at which star forming galaxies suffer a significant enhancement in their level of chemical enrichment. Using simple chemical evolution models that include the flow of baryons in and out of galaxies I will show how the MZR can be used to constrain the efficiency of star formation, the magnitude of gas outflows, and the physics of gas accretion into dark matter halos.

The Dark Energy Survey (DES) is 5-band optical survey designed to use four complementary cosmological probes (type Ia supernova, large-scale structure, weak lensing, clusters) to obtain the best constraints to date on the composition of the universe, particularly the time-evolution of dark energy.  In August, DES began the 4th observing season in its five-year, 525-night observing program using the wide-field DECam imager on the 4m Blanco telescope.  I will discuss the methodology, discoveries, and early results to date of the DES supernova program.  In particular I will highlight two lines of research being carried out using ESO facilities.  I will discuss how the systematic uncertainty in supernova cosmology due to correlations between type Ia supernova and their host-galaxy environments are being uniquely studied by DES with an ongoing large programme using X-shooter.  I will also talk about the rare and exciting class of transients called superluminous supernovae, and how DES is not only finding many of these objects with unparalleled data quality, but is also discovering new hints as to their progenitor systems.

The Sagittarius (Sgr) dwarf spheroidal galaxy and associated stellar streams provide valuable tools for the study of galaxy formation and evolution in the more massive surviving satellites of the MW as well as giving insights into the (dark) properties and assembly of the Galactic halo.
Using data from the Sloan Digital Sky Survey (SDSS), we construct accurate photometric colour-magnitude diagram (CMDs) and spectroscopic metallicity distribution functions of the different wraps of the Sagittarius stream. Through the accurate modelling of the CMDs, we determine the Star Formation History of the Sgr stream as a function of angle along the stream orbit and discuss the mix of stellar populations present in different wraps of the stream. This can be compared to the SFH of the Sgr core to determine when different parts of the stream were stripped from the host galaxy.
Furthermore, from spectroscopic abundances of stars in the Sgr stream, we construct the metallicity and alpha-element distribution of Sagittarius. These can be directly compared to abundances in the Galactic halo and other LG dSphs, to explore the range of masses of dwarf galaxies that could have contributed to the formation of the MW stellar halo system.

High imaging instrumentation have now enter its maturity, and all major 8 m class telescopes are now offering observation with such instruments, among which VLT/SPHERE, Gemini/GPI, Subaru/SCEXEO, Keck/NIRC2 and soon JWST/MIRI. However, the increasing complexity of the aperture geometry of the future space (WFIRST, LUVOIR) and ground based-telescope (E-ELT, TMT) will limit the performance of the next generation of coronagraphic instruments for high contrast imaging of exoplanets. We propose here a new closed-loop optimization technique to use the deformable mirrors to correct for the effects of complex apertures on coronagraph performance. This method is a new alternative to the ACAD technique previously developed by our group. This technique allows the use of any coronagraph designed for continuous apertures, with complex, segmented, apertures, maintaining high performance in contrast and throughput. Finally, this closed loop technique allows flexibility to adapt for changing pupil geometries (e.g. in case of segment failure or maintenance for ground-based telescopes), or "manufacturing imperfections in the coronagraph assembly and alignment. We present a numerical study on several pupil geometries (segmented LUVOIR type aperture, WFIRST, ELTs) for which we obtained high contrast levels with several deformable mirror setups (size, number of actuators, separation between them), coronagraphs (apodized pupil lyot and vortex coronagraphs) and spectral bandwidths. Finally, using the results of this study, we will present recommendations for future coronagraphic instruments.

Pierre Cox (ALMA Director) and John Carpenter (Observatory Scientist) will review the science highlights from the recent ALMA conference "Half a Decade of ALMA: Cosmic Dawns Transformed” held Sept 20-23 in California (see http://go.nrao.edu/ALMA5years ).

In LCDM theory, galaxy interactions play an important role in the growth of galaxies over time. However, the merger sequence and any consequent morphological transformation of low mass, dwarf galaxies, are not well constrained.  Dwarfs have higher gas fractions and higher dark matter to baryon ratios than more massive galaxies, suggesting their merger sequence could differ substantially from that of their more massive counterparts.  To date, the only existing detailed model of a dwarf-dwarf interaction is of the LMC/SMC, which is in close proximity to the Milky Way. In this talk, I present results of modeling the stellar and gaseous dynamical evolution of the dwarf pair NGC 4490/85 using the numerical code Identikit and SPH follow-ups. NGC 4490/85 is a pre-infall analog of the LMC/SMC, surrounded by a 50 kpc extended gas envelope and connected by a dense gas bridge. Using these models we explore the ability of  dwarf interactions to remove gas to large distances and estimate the gas removal and return timescale.

The K-band Multi-Object Spectrograph (KMOS) on the VLT is a powerful instrument for studying galaxy evolution across cosmic time. KMOS is a near-infrared (NIR) instrument with 24 integral field units (IFUs) each mounted on a robotic arm. Its NIR wavelengths and large field of view (7’ diameter patrol field) makes it ideal for investigating the properties of massive nearby galaxies, and galaxies in dense environments at redshifts z ~ 1-3.
I will first present work on a massive galaxy in the Local Universe, IC 1459. This bright early-type galaxy (ETG) is the archetype of a massive galaxy with a rapidly counter-rotating core. By using KMOS’s IFUs in mosaic mode, we generate over 45,000 spectra spanning IC 1459, allowing us to study it in unparalleled detail. We study dwarf-sensitive absorption features in the NIR to investigate the initial mass functions of the distinct components. These data are used to trace the kinematics and study the stellar populations of IC 1459 to better understand the origin of the counter-rotating core.
At higher redshifts, KMOS is ideal for studying the evolution of galaxies in dense cluster environments. I present new results from the KMOS Clusters Survey of one cluster JKCS 0141 at z ~ 1.8. The moveable IFUs allow us to target up to 24 targets in one observation. With this increased observing efficiency, we observe large spectroscopic samples of galaxies for over 20 hours on source, giving absorption line spectroscopy of massive cluster ETGs. At these redshifts, observed rest frame optical indices give information about how massive galaxies formed in dense cluster environments at early times.

Luminous Infrared Galaxies (LIRGs; L_IR [8--1000 um] > 10^11 L_sun) are the most extreme star forming systems in the local universe, in terms of their absolute star formation rates---tens to hundreds of times that of "normal" galaxies--and in terms of their star formation rate densities. Additionally, many LIRGs host active galactic nuclei, making these systems ideal for studying the co-evolution of galaxies and their supermassive black holes. The activity in LIRGs is generally driven by galaxy interactions and mergers, as these systems undergo a morphological transformation from disk to spheroidal systems. We currently lack a comprehensive understanding of galaxy-scale star formation and of the properties of the dense molecular gas which is fueling that star formation. A powerful tool to make progress is the detailed comparison between multi-wavelength observations with matched numerical simulations of individual local LIRG mergers. I will describe progress matching N-body simulations to individual LIRG mergers to provide context for observations and motivate follow-on hydrodynamic simulations to test star formation prescriptions. I will also discuss results from a millimeter survey and from targeted ALMA observations of dense gas tracers HCN and HCO+, the resulting constraints on the abundance and excitation of these species, and implications for the dense gas mass in IR luminous galaxies.

One of the most characteristic features of galaxy clusters is the so-called “red sequence” (RS) that early-type galaxies form in the color-magnitude space of filters chosen to straddle the rest-frame 4000 A-break feature in galaxy spectra. Since these galaxies are, in general, devoid of gas and dust, their red colors are mainly a consequence of their passive nature. The denser cluster core is dominated by these “red-and-dead” galaxies, some of them the most massive galaxies known. However, the physical mechanisms responsible for quenching their star formation, thus originating the RS, are poorly understood. Environmental effects should play a significant role in the formation of the RS by transforming the observed galaxy properties from late- to early-type ones. However, the details of how this actually happens are still unclear. I will present part of the work in progress that our team is carrying out to better understand whether nature or nurture dominates in cluster galaxy evolution and the formation of the RS. Results so far are based on the study of cluster galaxies at 0.8<z<1.7, an epoch of active stellar mass build-up and large-scale structure assembly in the universe.

Abstract: Stellar activity can cause difficulties in accurately determining the planetary parameters through spectroscopic and photometric observations. I will discuss how the overlap of a transiting planet and stellar active regions can produce anomalies in the transit light curves which can lead to inaccurate estimation of planet radius by 4%, and also can produce transit timing variations signal with the amplitudes of 200 seconds. I will talk also about how these anomalies can affect the transmission spectroscopy’s measurements and how easily can mimic the signature of Rayleigh scattering in the planetary atmosphere. Rossiter-McLaughlin (RM) effect, which is the spectroscopic transit observations, has been used to estimate the spin-orbit angle of planetary systems. Since the physics and geometry behind the transit light curve and RM are the same, the RM observations are expected to be affected by the occultation of stellar active regions in a similar way. I will show that inaccurate estimation on the spin-orbit angle due to stellar activity can be quite significant (up to 30 degrees), and demonstrate that the aligned transiting planets are the ones that can be easily misinterpreted as misaligned owing to the stellar activity.

The mass retention efficiency is a key question in both the theoretical and observational study of accreting white dwarfs (WDs) in interacting  binaries, with important implications for their potential as progenitors for type Ia supernovae (SNe Ia). Canonical wisdom is that classical nova eruptions erode the WD mass (e.g. Prialnik & Kovetz, 1995), and consequently, Cataclysmic Variables (CVs) have been excluded from the SN Ia progenitor discussion. However, Zorotovic et al. (2011) showed that the average mass of WD in CVs is substantially higher (~0.83 Msun) than that of single WDs (~0.64 Msun), in stark contrast to expectations based on current classical nova models. This finding is based on a sample of ~30 CV WDs with accurate mass measurements, most of them in eclipsing systems.


Given the fundamental importance of the mass evolution of accreting WDs, it is necessary to enlarge this sample and to diversify the methods used for measuring masses. We have begun a systematic study of 40 CVs using 122 orbits of HST ultraviolet spectroscopy and several nights of VLT/X-Shooter observations. We used a grid of synthetic spectra to determine the WD effective temperature (Teff) and surface gravity (log(g)). The HST spectra alone cannot resolve the degeneracy between Teff and log(g), and an additional dynamical constraint is needed. We use the phase-resolved X-Shooter observations to (i) measure the mass ratio of the CVs from the reflex motion of both the WD and the donor star (ii) to establish the spectral energy distribution (SED), which constrains both Teff and log(g). Combining the X-Shooter and HST data, we can measure the WD masses to a few percent, and will be able to answer the question whether accreting CV WDs grow in mass.

One of the main observational challenges for investigating the central regions of active galactic nuclei (AGN) at short wavelengths, using high angular resolution, and high contrast observations, is to directly detect the circumnuclear optically thick material hiding the central core emission when viewed edge-on. The lack of direct evidence is limiting our understanding of AGN, and several scenarios have been proposed to cope for the diverse observed aspects of activity in a unified approach.

We therefore set two years ago a program of high angular resolution polarimetric imaging of nearby AGN taking advantage of the new SPHERE high contrast and polarimetric capacities. In contrast with pure imaging dominated by the point like core of hot dust, polarimetric imaging gives access to the colder extended part of the elusive torus in an AGN, because it traces scattering or dichroic absorption by dust grains. Broad-band polarimetric images in Ks and H of NGC 1068, one of the closest and most studied Seyfert 2, taken during SPHERE Science Verification program, indeed revealed a clearly elongated structure at a scale of a few tens pc, bracketing the quasi point-like central source.

We use MUSE to study the kinematics, chemistry and star-formation history across NGC 4371, an early-type massive barred galaxy in the core of the Virgo cluster. We complement this study with multi-component decompositions using images from HST and Spitzer. We show that the rotationally supported inner components in NGC 4371, i.e. an inner disc and a nuclear ring - which, according to the predominant scenario, are built with stars formed from gas brought to the inner region by disc instabilities such as bars - are vastly dominated by stars older than 10 Gyr. Our results thus indicate that the formation of the bar in NGC 4371 occurred at a redshift of about $z=1.8^{+0.5}_{-0.4}$ (error bars are derived from 100 Monte Carlo realisations), and that bar-built central structures can be dominated by old stellar populations. Furthermore, our results imply that the disc in NGC 4371 is already dynamically mature at z~1.8, because bars do not form in discs with an excessive degree of dynamical disorder. We are now extending this study to a volume-limited sample drawn from the S4G (the Spitzer Survey of Stellar Structure in Galaxies) with a range of stellar masses. This allows us to provide constraints to the formation of galaxy discs, and test the downsizing scenario, in which more massive discs form first.

I present our analysis of the center-to-limb variation in the strong
Fraunhofer lines of the planet host star HD 189733.
The stellar disk shows a limb-angle dependent variation in brightness. In transit modeling
this effect is known as limb darkening or, more generally, center-to-limb variation.
The center-to-limb variation is not limited to the brightness, but
also affects the strength and profile of individual spectral lines.
The spectral change can be observed during planetary transits, when the
planet eclipses specific sections of the otherwise unresolved stellar disk.
In our analysis of VLT/UVES transit spectroscopy of HD 189733, we clearly detected the spectral
center-to-limb variation in the Ca II H and K and the Na D lines. This effect allows spatially
resolved studies of the stellar disk and has to be taken into account in accurate
modeling of planetary transit spectroscopy and the study of planetary atmospheres.

Galaxy evolution and formation has been extensively studied in the past decades. In numerous studies two main parameters are widely used, namely
the star formation rate (SFR) and stellar mass (M*). They allowed the estimation of the evolution of the luminosity function, SFR density and Mass
functions at different epochs which brought important constraints on the physical processes driving the evolution of galaxies.

In this work we choose to study another crucial parameter, the age of galaxies; a parameter that is in general left apart due to the degeneracies with other
parameters like dust and metallicity. Nevertheless,  I will show, with large simulations, that the estimation of galaxy ages is possible when we use high redshift
galaxies (z>2) and the coupling of UV-rf spectroscopy and multi-wavelength photometry. Using this method applied to the galaxies of the VIMOS Ultra deep survey
I will discuss the implications of the estimation of high redshift galaxy ages.
First, I will present the estimation of the formation redshift of galaxies, e.g. the redshift (or epoch) at which the star formation in the galaxy was ignited. These
measurements are then used to estimate the formation redshift function (FzF), a new way to trace galaxy formation across cosmic time. It describes the number
of created galaxies at any particular epoch in the history of the Universe. This allows us to follow the formation of galaxies up to very early time at z~>10-15.
Then, using these formation redshifts and stellar mass I will present the last results on the mass assembly of galaxies. I will show that there is a strong correlation
between these two parameters at low redshift while this correlation is continuously reduced with redshift to almost a non-correlation at the highest redshift.

To conclude I will present the next steps that will be developed in the future to extend this work at other cosmic epochs.

TBD

In this talk I will give an overview and update of two current Australian lead projects: SkyMapper and OzDES.

Now in full operation, the SkyMapper Telescope is a 1.3m wide-field robotic optical telescope located at Siding Spring Observatory in Australia. SkyMapper is performing a digital Southern Sky Survey in six filters (uvgriz). The SkyMapper Supernova program searches ~1000deg2 per night with a 3-4 day cadence. SkyMapper is expected to discover 50-100 type Ia supernovae (SNe Ia) at redshift z < 0.1 per year, with photometry in four colours (vgri).

In collaboration with the Dark Energy Survey, OzDES is using the AAT to derive what will be the tightest constraints yet on the dark energy equation-of-state parameter.  Using the AAOmega spectrograph it obtains redshifts for objects in the DES fields. While probing dark energy using type Ia supernovae is the prime aim of the survey, the observing strategy enables us to conduct a number of other investigations, such as AGN reverberation mapping and galaxy properties.

Studying exoplanets, and in particular gaseous giant planets, is a new field of modern astrophysics. Understanding how the giant planets form, dynamically evolve, evolve with time, and have an impact on potential other planets within a stellar system are part of the biggest challenges of this science. The development of the most efficient observational technics and optimal analysis tools have been necessary to bring answers to these problematics.

My research topic is part of this new science, and focuses on the search for and the study of some statistical aspects of giant planets around low-mass stars. I will present in this talk the results that I have obtained during my PhD. First, I will introduce to you my statistical analysis of the giant planet population as a function of stellar mass, MASSIVE. I will then present the statistical tool that I have developped to probe the giant planet population at all separations from the star, MESS2, that is based on the combination of direct imaging and radial velocity data.

We introduce the Laser Frequency Comb (LFC) optimized for Astronomical applications,
and discuss our experience of the LFC on HARPS.

We show some of the latest findings on the LFC+HARPS data and discuss future plans 
to optimize data acquisition and reduction strategies.

Finally we mention future applications for the LFC in La Silla, Paranal, and Armazones. 

In this talk I will present new, wide-field, optical (u'g'r'i'z') Dark Energy Camera observations covering ~72 sq. deg. centred on the nearby giant elliptical galaxy NGC5128 (Centaurus A) called ``The Survey of Centaurus A's Baryonic Structures'' (SCABS). I will briefly describe the data reduction and analysis procedures that lead to 50 and 90 percent point-source completeness limits of at least u'=23.62 mag (AB), g'=22.27 mag, r'=22.00 mag, i'=21.63 mag, and z'=21.34 mag. From the resulting catalogues of 5-15x10^5 detected sources, optical colours are combined with source morphologies to compile a new catalogue of 2676 globular cluster (GC) candidates, of which 2404 are newly identified, which includes the vast majority of GCs within ~140 kpc of NGC5128. Evidence is presented for a transition at a galactocentric radius of R_{gc}~55 kpc from GCs “intrinsic” to NGC5128 to those likely to be part of the intra-group medium of the Centaurus A galaxy group. Inside this transition radius, the red GC subpopulation is more centrally concentrated than the blue, with surface number density profiles of the form Σ_{N,red} ~ R_{gc}^{-1.88} and Σ_{N,blue} ~ R_{gc}^{-1.50}. Both in- and out-ward of the transition radius, the number of blue GCs dominates over the red GCs, indicating a lively history of minor-mergers during NGC5128’s past. Assuming the blue GCs to have origins primarily in dwarf galaxies, we estimate the population of dwarfs required to explain them, while simultaneously remaining consistent with NGC5128’s present-day spheroid luminosity. It is found that several dozen dwarf galaxies of luminosities L_{dw,V} ~ 10^{6-9.3} L_{V,sun}, following a Schechter luminosity function with a faint-end slope of -1.50 < α < -1.25 is favoured, the majority of which are likely to have already been disrupted in NGC5128’s tidal field.

Magnetic fields are of fundamental importance for the intermediate-mass star formation and accretion-ejection processes.
Models of magnetically driven accretion and outflows successfully reproduce many observational properties of
the classical T Tauri stars, but the picture is less clear for higher-mass stars, the Herbig Ae/Be stars,
due to the poor knowledge of their magnetic field topology. So far, the magnetic field geometry is constrained only for two Herbig
Ae/Be stars, and only about 20 Herbig stars were reported to host magnetic fields. Studies of the magnetic field topology using spectropolarimetry are extremely important
because they enable us to improve our insight into how the magnetic fields in these stars are generated
and how they interact with their environment, including the impact on the planet formation processes and
the planet-disk interactions. In this talk, I will present the status of the spectropolarimetric studies of
Herbig Ae/Be stars carried out during the last years.

In the recent years, the interest on studying the outer parts of spiral galaxies is rising. To better understand galactic formation and evolution, simulations and observations are working together to understand the different behaviours that the disc light distribution displays in the outer parts of these systems. During this talk I will speak about my work as part of my PhD thesis focused on the stellar content in these outer regions. We have implemented a new methodology to analyse the stellar content from spectroscopic data based on the state-of-art full spectrum fitting techniques (using GANDALF and STECKMAP). We have tested such methodology on the LMC bar region, where high quality integrated spectra can be obtained as well as Color-Magnitude Diagrams reaching the oldest Main Sequence Turnoff. I will also show what we are obtaining when applying such methodology to the smallest galaxies observed in the CALIFA (Sánchez et al. 2012) survey. I will compare such observational results with what recent simulations (RaDES, Few et al. 2012) suggest. I will finish showing the effect that satellite accretion has on shaping the chemical and kinematic properties of the outskirts of simulated galaxies, as well as the effect of such accretion in the shape of the stellar age profile as shown by the RaDES set of galaxies.

Near-Earth asteroids (NEAs) played an important role in the emergence of life on our planet, with the delivery of water and organics to the early Earth, where these materials couldn't accrete. However NEAs also pose a hazard to the Earth, as asteroid and comet impacts could significantly affect our civilization.
I will report about our ongoing 2-year Guaranteed Time Observations (GTO) programme at ESO-NTT, started in April 2015 in the framework of the European NEOShield-2 project. The main aim of this GTO programme is to undertake - for the first time ever - a comprehensive characterization of the physical properties of the "small" (< 300 m) NEA population. Indeed, the small sized objects are particularly important to constrain the asteroidal contribution to the delivery of water and organics on Earth, as water is vaporized and complex organic molecules are broken when too large impacts happen. Also in terms of the current impact risk, the "small" objects deserve our particular attention, as they have the highest statistical likelihood of impact, and can still produce a catastrophe at a regional/national scale.

The discrepancy between chemical abundances computed using optical recombination lines (ORLs) and collisionally excited lines (CELs) is a major unresolved problem in nebular astrophysics, and has significant implications for the determination of chemical abundances throughout the Universe. In planetary nebulae, the most common (but ad-hoc) explanation of the discrepancy is that two different gas phases coexist: a hot component with standard metallicity, and a much cooler plasma with a highly enhanced content of heavy elements. This dual nature is not predicted by mass loss theories, and observational support for it is still weak.
In this talk, I will present recent findings which demonstrate that the largest abundance discrepancies are reached in planetary nebulae with close binary central stars.  Our ISIS-WHT and FORS2-VLT spectroscopic analysis supports the previous interpretation that two different gas phases coexist in these nebulae. Our observations have added a new unexpected ingredient to understand the abundance discrepancy problem: high adfs should be explained in a framework of binary evolution. OSIRIS-GTC TF imaging of the faint O II RLs are used to confirm that the gas emitting these lines presents a different spatial distribution than the gas emitting [O III] CELs. I will briefly discuss some of the proposed explanations.

Our Milky Way’s center contains the typical ingredients of a galactic nucleus, which are a massive black 
hole and nuclear star cluster. Since it is the only such system that we can study in detail, it is of central 
astrophysical interest. In this talk I will review the current state of our knowledge on the structure and 
dynamics of the nuclear star cluster. In particular I will focus on the key question of whether or not there 
exists a stellar cusp around the central black hole, Sagittarius A*,  and present new observational analyses 
aimed at answering this question. I will briefly introduce our GALACTICNUCLEUS high angular resolution 
JHK survey of the inner few tens of parsecs of the Galactic Center. Finally, I will present recent results from
the measurements of short-period stars around Sagittarius A*.

The AM CVn stars are a small class of compact, helium-accreting white dwarf binaries. I will present a brief overview of the known population, and compare their properties with the more common hydrogen-rich cataclysmic variables. I focus specifically on the impact of photometric transient surveys on our knowledge of these binaries - both in terms of the discovery of new systems as well as the insights gained from follow-up observations of transient events.

In massive galaxy clusters the interactions between galaxies and cluster gas as the galaxies enter the cluster for the first time may lead to quenching of the star formation. This interaction transforms them into passively evolving bulge-dominated galaxies. With the Gemini/HST Galaxy Cluster Project we aim to map the evolution of these bulge-dominated cluster galaxies from z~2 to the present. Here we present evidence for a redshift 1.27 cluster “caught-in-the-act” of quenching the star formation. The Lynx W cluster contains a significant population of bulge-dominated galaxies with very young stellar populations and/or low-level star formation. The population is present throughout the cluster.We link this population to our larger sample of bulge-dominated galaxies in rich clusters spanning from the present to redshift 1.27. Our data currently cover eight clusters at z=0.2-1.27 with deep spectroscopic data and Hubble Space Telescope imaging. We find significant cluster-to-cluster variation of the galaxy populations, but also the expected signature of passive evolution of bulge-dominated galaxies from z~1.3 to the present.

Luminous Blue Variables (LBVs) are massive stars caught in a post-main sequence phase, during which they are losing a significant amount of mass. Given the potential importance in its evolution of the binary nature of the most dramatic example of the class, eta Car, and the fact that most massive stars are thought to be close binaries, it would be useful to find other binary LBVs. We present here interferometric observations of the LBV HR Car done with the AMBER and PIONIER instruments and ESO's Very Large Telescope Interferometer. Our observations, spanning two years, clearly reveal that HR Car is a binary star and we have detected the orbital motion, leading to an orbital period between 5 and 80 years. Our results show that the LBV HR\, Car is possibly another $\eta$~Car-like binary system, showing possible signs of interaction at periastron and further monitoring of this object will clearly constraint the orbit and the total mass of the system.

During planet formation, minor bodies can get trapped and grow in the Lagrangian gravity wells of a planet-star system. These objects, called trojans, co-orbit with the planet. They are thus outgrowths of planet formation and early evolution processes, so their mere existence and characterization can provide key information about the first stages of the life of planetary systems. The most well-known trojans are located in Jupiter's L4 and L5 points, but other planets like our own Earth also host trojan bodies. In the Solar System, their wide variety of properties (libration amplitudes, inclinations, etc.) are providing important hints on the history of our planetary system. Consequently, the detection of the first exotrojan bodies will open a new scientific window to unveil planet formation and migration in outer systems. In this context, we have started the TROY project, a multi-technique effort to find these bodies around known extrasolar planets. In this talk I will present the main goals of the project and the scientific outcomes that will be extracted from our joint observational and theoretical plan.

Classical Cepheid variables, being relatively young stars, can be used to
trace the position of the spiral arms. Unfortunately, their position in
the Galactic disk results in them having excessive amounts of reddening,
which so far has prevented their discovery in the farthest regions of the
Milky Way.

In recent years, the Vista Variables in the Vía Láctea (VVV) project has
completed a ~520 square degree YZJHKs multi-color, and Ks band multi-epoch
survey of the southern Galactic disk and the Galactic bulge, utilizing the
VIRCAM camera of the 4.1m VISTA telescope at Paranal Observatory. The
greatly diminished extinction in the near-infrared bands enables the
discovery of classical Cepheids as far as the far side of the Galactic
disk. The VISTA Galactic Cepheid Program (VGCP) aims to find the so far
uncovered Cepheid population of the Milky Way. We have already discovered
a twin Cepheid pair behind the Galactic bulge, indicative of a parent open
cluster which is completely hidden by the high extinction in the plane, as
well as a thin disk of classical Cepheids within the volume of the Galactic
bulge, a hitherto unknown stellar population in the Milky Way.

I present the current status of the VGCP and the follow-up observations
undertaken to characterize the Cepheid variables of the VVV survey, and
through them, the far disk of the Milky Way, as well.

Results from ALMA Long Baseline observations and from SPHERE, GPI and other high-contrast AO instruments have given a taste of what to expect over the next few years in the fields of protoplanetary and debris disks, and planet formation. For the first time, these instruments are enabling us to observe the regions where planets form. Already we are finding gaps, holes, spiral wave patterns, and extreme asymmetries in the disks.

Substantially different structures are seen in various molecules and in different dust grains, and the first evidence for the detection of young planets is starting to emerge.

With the few-AU scales now resolvable, we can also start to unravel the complex dynamical interaction between the disks, accretion, jets and winds, and how these affect the growing planets.

Some of these spectacular features had been predicted by theory but confrontation with current models indicates clearly that we still have much to learn about what happens within 100AU of young stars.

We will host an ESO planet formation workshop in 2016 to discuss the state of the art results in this field. The program will offer a panchromatic view of the latest results, with an adequate balance between observations and theory.  The timescale for this international conference is propitious, fostering discussions on how upcoming facilities (such as JWST, TMT and eELT) and advances in modeling will tackle planetary formation in the next few years.

The protoplanetary disk around the F-type star HD 135344B (SAO 206462)
is in a transition stage and shows many intriguing structures both in
scattered light and thermal (sub-)millimeter emission which are
possibly related to planet formation processes. We have carried out
multi-wavelength, multi-epoch VLT/SPHERE polarimetric differential
imaging (PDI) observations which revealed the spiral arms and dust
cavity in great detail. In addition, multiple shadow features were
detected which are likely cast by structures in the innermost disk
regions. Interestingly, one shadow was only detected in the second
observation epoch which points to a transient or variable source of
this shadow. The shadow features and their possible variability have
the potential to provide new insight into the innermost disk regions
of HD 135344B which are out of reach for the high-contrast imager
VLT/SPHERE.

I will present an update on some of the results from the ESA Rosetta mission to comet 67P/Churyumov-Gerasimenko, covering some of the unexpected results to date. These include the discovery of many new molecules in the coma, and new ideas on how comets (and Kuiper Belt objects) formed. I'll also show some of the latest images from the mission.

Understanding of the chemical enrichment of galaxies is of
fundamental importance for our complete understanding of the Universe.
However, extragalactic measurements of metallicity are almost
exclusively achieved through emission line diagnostics, which are plagued with
systematics. In this TMT, I present both models and observations that
show type II supernovae (SNeII) can be used as complementary metallicity indicators.
Spectral models present increasing metal-line strengths with increasing
progenitor metallicity. We confirm this trend observationally by
showing that the equivalent width of Fe 5018A
measured in SNII spectra at 50 days post explosion has a statistically
significant correlation with SN host HII region oxygen abundance.
The implications of this trend are explored, together with an outlook to
future uses of SNeII in this context.

Extrasolar planets abound in almost any possible configuration. However, until five years ago, there was a lack of planets orbiting closer than 0.5 au to giant or subgiant stars. Since then, recent detections have started to populate this regime by confirming 13 planetary systems. In this talk I will summarize the results of our recently accepted paper (Lillo-Box et al., 2016) on the properties of these planets in terms of their formation and evolution off the main sequence. Interestingly, we find that 70% of the planets in this regime are inner components of multiplanetary systems. This value is 4.2σ higher than for main-sequence hosts, which we find to be 42%. I will provide the possible interpretations of this observational difference and their implications in our knowledge of the processes of planet migration and planet engulfment.

Recent observations of gamma rays together with microwaves and polarized radio waves, have detected giant lobes of plasma (Fermi Bubbles) extending above and below the Galactic plane of the Milky Way. These are possible signs of a Nuclear wind powered by either the central black hole or concentrated nuclear star-formation; but our understanding of their origin is hampered by a lack of kinematic information. I will report new observations from a systematic, absorption-line survey that maps the spatial and kinematic properties of the biconical nuclear outflow, using UV spectroscopy of AGN and halo stars lying close on the sky to the Galactic Center. The variation in absorption properties with Galactic latitude allows us to constrain the physical conditions in the outflowing gas. The observed kinematics of absorption components will be discussed and compared to predictions from biconical outflow models. I will show that the observed absorption profiles can be explained by a biconical nuclear wind with a radial velocity of ~ 1000 km/sec, and constrain the kinematic age of the Fermi Bubbles to be ∼6–9 Myrs. Using these estimates, I will constrain the minimum mass of UV absorbing gas entrained in the Fermi Bubbles. These observations illustrate the novel use of UV spectroscopy to constrain the feedback processes that regulate galaxy evolution.

The widely-accepted standard picture of accretion onto supermassive black holes postulates the presence of a geometrically and optically thick “dusty torus”. This torus is thought to be responsible for the infrared emission, which accounts for about half of the total emitted power from these active galactic nuclei. Since the torus is too small to be resolved with single telescopes, our knowledge of the structure of this region relies heavily on a combination of spatially unresolved data and models. Recent advances in interferometry have allowed us to resolve the dust emission and showed in few sources that the bulk of the infrared emission originates from the polar region of the putative torus, where no or only little dust should be present. But it has remained unclear whether these objects are anomalies. Here we show that  polar infrared emission is very common in active galactic nuclei and that it can be detected even with single telescopes, thus extending far beyond the physical scale of the putative torus. This is inconsistent with current models and supports the idea that the majority of the infrared emission is related to a dusty wind. Indeed, we demonstrate that the detectability of polar infrared features is tightly related to the strength of the emission from gaseous outflows. This result demands a new paradigm for the infrared emission structure in active galactic nuclei.

The South Pole Telescope unveiled a population of dusty, star-forming galaxies magnified by strong galaxy-galaxy lensing. We determined the redshift of 39 of these sources through ALMA millimeter spectroscopy and found a median redshift of 3.9 and a maximum of 5.8. An ongoing ALMA program targeting the reddest SPT sources should find even higher redshift. This sample of strongly magnified objects at high redshift offers a unique opportunity to study the cold interstellar medium (ISM) of distant galaxy. In addition, models predict that this population should contain a mix of starbursts and massive main-sequence galaxies. I will review the main results of the SPT collaboration about the properties of the ISM of these galaxies. Fine structure lines are also a very promising tracer of the ISM of these high-redshift objects. I will present a pilot study based on SPT2132-58 for which 3 fine-structure lines were detected ([NII], [CII] and [CI]. This extreme  starburst at z=4.77 has an extremely short depletion timescale of 37 Gyr with a relatively mature ISM. Explaining the existence of so evolved galaxies at such high redshifts will by a stimulating challenge for galaxy evolution models.

As early as 1978, when an ambitious next telescope began to be considered by ESO, the idea of an interferometric optical array emerged. It took more than ten years to discuss and establish the feasibility of the idea, and to implement it as an intrinsic part of the VLT project, including the Auxiliary telescopes. Both superb opticians within ESO and astronomers in Europe worked hard for this demonstration, which on its way led to the development of adaptive optics, soon to become an independent and highly productive route. After the VLT was formally approved, the real work began, with ups and downs, until VLTI finally had its first light with ATs, then UTs, in 2001. The VLTI scientific production has not stopped since then. What will be the next step in optical and infrared interferometry ?

The study of the substructures present in the Galactic halo provides vital information about its origin and history, as well as constraints on the models of hierarchical galaxy formation and evolutionRR Lyrae stars have proven to be excellent tracers of halo substructures, due to the quality of the distances that can be derived from them, and the relatively straightforward methods that lead to their clean identification.

In this talk I will present the techniques we have used and developed to unveil halo substructures using RR Lyrae stars. In particular, I will describe how we discovered the complex substructure in the direction of the Virgo Overdensity. I will show how we are studying the nature of its velocity components and in which directions we are advancing towards the understanding of the origin and characteristics of the underlaying potential progenitor.

I will also present a survey we are conducting using Catalina Real-time Transient Survey RR Lyrae data in the southern sky, and how our preliminary results connect with our initial discoveries in the Virgo overdensity region.

Protostars drive energetic jets that entrain surrounding gas in the form of outflows, simultaneously injecting momentum in the surroundings.  Hence, outflows are a bridge for feedback from individual protostars to their nascent cluster environment.  Observations of outflows and their impact on clusters are challenging because they must probe spatial scales over several orders of magnitude --- from the size of a protostar envelope (a few hundred AU, or 0.003 pc) to a cluster (a few pc).  My work incorporates high-resolution, high-sensitivity interferometry observations (with millimeter/sub-millimeter wavelengths) complemented by observations obtained using single dish telescopes in order to assess molecular outflow properties and their cumulative impact in young protostellar clusters.  In this talk, I will present multi-scale observations of the Class 0 source CARMA-7 in Serpens South, ``zooming-in’’ from the cluster-scale to the episodic outflow, and finally to the rotating and infalling envelope fueling accretion onto a forming disk and protostar.

I will present the MUSE Atlas of Disks (MAD) survey (PI: Marcella Carollo). MAD is a MUSE-GTO program obtaining spectroscopic data for a large representative sample of nearby (z=0) star-forming Main Sequence disk galaxies with known structural and colour properties from HST imaging. The great quality of MUSE data (higher spatial and spectral resolution and greater depth than any other IFU data on these systems) enables to obtain 2-D chemo-dynamical maps at scales < 100 pc out to 2 scale-lengths. At these scales, accurate studies of the stellar and
gaseous kinematics and absorption/emission line properties (stellar populations, metallicity, dust extinction, SFRs, ISM properties) will help to advance our understanding of how disk galaxies grow in size and mass with cosmic time, establish the dynamical state of inner disks and bulges and their star-formation histories, quantify gas in/outflows, shocks, kinematic and chemical/population signatures of accretion events, reveal connections between baryonic and dark matter halo properties and many more. In this talk I will give a brief description of the MAD sample selection, a global summary of the current observations and present the preliminary results we are obtaining with the galaxies observed so far.

There is a growing notion that the formation of massive galaxies must be a two-phase process, with a late phase that is dominated by galaxy mergers and an early phase that is driven by cold gas accretion. I will present observational evidence for large (~100 kpc) reservoirs of very cold molecular gas in the halo-environments of proto-cluster radio-galaxies at z~2. We discovered that this cold molecular medium is related to a variety of important evolutionary processes, from cold gas accretion to jet-induced feedback and galaxy merging. These processes may help explain how giant galaxies were created out of large amounts of very cold gas. This work is based on low-surface-brightness observations with ALMA, VLA and ATCA. I will how how these instruments nicely complement each other for studying the cold molecular medium in the Early Universe.

I will discuss the results of three major programs of studying star formation, cold gas, feedback and dynamics of massive 'normal' star forming galaxies near the peak of the epoch of galaxy formation (z~1-3). Our observations were carried out with the IRAM Plateau de Bure interferometer and with large instruments developed with significant or leading MPE participation (the VLT near-IR integral field spectrometers SINFONI and KMOS, and the far-IR spectrometer/photometer PACS on Herschel). When combined, those studies clearly show that massive star forming galaxies near the star formation-stellar mass 'main-sequence' were gas rich, highly turbulent and clumpy, disky systems with various degrees of rotational support. Star formation in these galaxies was plausibly driven by continuous, rapid accretion of gas and minor mergers from the cosmic web. The evolution of their disks and central bulges was probably strongly influenced by disk fragmentation and instabilities, as well as by powerful galactic outflows driven from the large star forming clumps and AGN. I will discuss the impact of these new observations on our understanding of galaxy evolution in the early Universe.

We discovered in 2013 using NACO that the nearby AGB star L2 Pup (64 pc) is surrounded by a spatially resolved dust disk seen almost edge-on (Kervella et al. 2014, A&A, 564, A88). We also detected the thermal emission from an enigmatic dust "loop" extending to more than 10 AU from the star. As the light scattering is inefficient at IR wavelengths, we observe essentially the thermal emission from the central part. We observed again L2 Pup in Dec. 2014 at visible wavelengths using the new VLT/SPHERE adaptive optics, equipped with the ZIMPOL imaging polarimeter (Kervella et al. 2015, A&A, 578, A77). Thanks the remarkable angular resolution of these images (<20 mas), we identify a number of features in the disk, as well as a close-in companion. The degree of linear polarization help us constrain the three-dimensional structure of the envelope.
L2 Pup is currently a relatively "young" AGB star, so we may witness the beginning of the planetary nebula formation process. Our first hypothesis is that this dust disk is a key element in the future formation of a bipolar nebula. Other open questions are related to the origin of the disk and other features observed around L2 Pup. The physical process that breaks the (probably) spherical symmetry of mass loss from the AGB star is currently uncertain, but the disk and companion probably play a key role.
I will concluding by a brief discussion of the observational perspectives on this remarkable object.

The Multi-Object Optical and Near-IR Spectrograph MOONS, to be installed on the VLT, is expected to begin operations in 2019-2020. MOONS combines a high multiplexity (~1,000 fibres) and high throughput in near-IR wavelengths at high resolution (R~19,000 in H-band) thus offering a powerful facility for Galactic archaeology. MOONS technical specifications, powered by the 8.2m telescope aperture of the VLT, make it the ideal workhorse to map the highly obscured regions of the Galaxy. As an example case, I will describe the plans of our MOONS Inner Galaxy Legacy Survey, currently in its design stage. I will describe its complementary nature with other Galactic archaeology surveys, highlighting the wide range of science cases that can be addressed from MOONS mapping the southern disk and bulge at low Galactic latitudes. In this context, I will show the strong synergy of MOONS with the Vista Variables and the Via Lactea (VVV) survey and its planned extension (VVV-X), to emphasise how important legacy surveys are for delivering products to the community.

The European Space Agency's Rosetta mission captured the imagination of the world in 2014,
as it rendezvoused with Comet 67P/Churyumov-Gerasimenko and deployed a lander, Philae, to
its surface. In this talk, I'll give a behind-the-scenes view of the mission, its history,
the 10-year journey to reach the comet, and the exciting events that have been taking place
there. I'll talk about some of the challenges and risks involved in the mission, and give
some insights into the key scientific findings revealed to date about the formation of our
solar system, the origins of water and perhaps even life on Earth. And to end, a look forward
to the final phase of the mission, now that Rosetta, Philae, and the comet are past their
closest approach to the Sun and heading back out into the cold.

For a long time globular clusters have been recognized as simple objects - consisting of a single stellar population that was formed several billion years ago. However, over the last year high-resolution photometric and spectroscopic studies have shown that at least two stellar populations exist in almost all globular clusters. This discovery raised new questions - for example, if the different populations show distinct dynamical properties. Despite the short relaxation times of most clusters, there is evidence that the abundance of binary stars is lower in the second that in the primordial population. It is not only the question of multiple populations where binary stars play an important role for our understanding of globular clusters. Another example is their influence on the timescale at which the cluster undergoes core collapse. In addition, binaries allow one to inverstigate the spatial distribution of stellar remnants, such as neutron stars or black holes. Their distributions strongly affect the central kinematics of the clusters and hence are important to answer the question if globular clusters host intermediate-mass black holes. With masses in the range of 100 to 10,000 solar masses, these objects would fill the gap between stellar black holes and the supermassive ones that are found in the centres of galaxies. Answering the questions raised above is only possible by acquiring large spectroscopic samples of cluster stars. With the development of techniques that strongly enhance the efficiency of spectroscopic observations in globular clusters this now allows us to obtain and analyse samples of 10,000 stars per cluster in moderate observing times. Currently we are conductiong a large programme (about 100 hours of observing time) with MUSE that targets 25 Galactic globular clusters with the aim of adresing these points

The young, nearby moving groups offer us one of the best opportunities to study
discs, planets and binary stars due to their proximity (< 200 pc) and youth (10-100 Myr).
I will present results from a series of stellar multiplicity studies we have conducted in these
populations.  We have combined a number of observational techniques (spectroscopy, 
interferometry,  AO-imaging and direct imaging / kinematics) which allows us to look for
companions over the separation range 0.01-100,000 au, and derive robust detection limits.

We recently identified many new wide companions in these populations.  The high number 
of identified companions lead us to investigate their potential formation scenarios, as in-situ
wide binary formation is highly improbable.  Thanks to our previously derived detections 
limits we were able to study the rate of higher-order (triple, quadruple etc.) multiplicity 
within these systems.  We found a strong preference for wide systems to have 3 or more
components. This is in agreement with the formation mechanism outlined in Reipurth 
and Mikkola 2012; whereby stars are born in clumps with 3 or more components and migrate
to their current positions via the exchange of angular momentum.   These results, combined
with recent Class 0 multiplicity studies, lead us to conclude that the majority of solar-mass
stars are in fact likely born in triple, or higher-order, systems.

Hot subdwarf binaries are evolved core He burning stars with very thin hydrogen envelopes (<0.1 Msol). The only way to form these stars is through binary evolution, which makes then interesting objects to study binary evolution methods.

Hot subdwarf-B stars in long period binaries are found to be on eccentric orbits, even though current binary evolution theory predicts these systems to circularise before the onset of Roche-lobe overflow.

We aimed to find binary evolution mechanisms that can explain these eccentric long period orbits, and reproduce the currently observed period-eccentricity diagram. Three different processes are considered; tidally enhanced wind mass loss, phase dependent RLOF on eccentric orbits and the interaction between a circumbinary disk and the binary. To test these processes they were implemented in the binary module of the stellar evolution code MESA.

We find that a combination of phase dependent mass loss and circumbinary disk interaction can explain the eccentricities of the observed systems, but the models are unable to reproduce the observed trend of higher eccentricities at longer orbital periods. Further observations in combination with theoretical modeling will hopefully solve this discrepancy.

TITLE: V-type asteroids: a tale of two parent bodies?
ABSTRACT: In recent years several small basaltic (or V-type) asteroids
have been identified all around the Main Belt. Most of them lies inside
the 3:1 mean motion resonance with Jupiter and are members of the Vesta
dynamical family (Williams 1989), but an increasingly large number in the
middle and outer main belt appears to have no dynamical link with it
(Lazzaro et al. 2000, Binzel et al. 2006). The arising question is whether
these basaltic objects do indeed come from Vesta.
To resolve the conundrum, we performed a statistical analysis of the
spectroscopic and mineralogical properties of a large sample of V-types,
in order to highlight the spectroscopic similarities and differences among
them, which could shed light on their unique (or not) origin.
We computed several parameters in the visible, near-infrared and VNIR
ranges diagnostic of mineralogy, with a particular attention to Band
Minima and Band Centres, the position of the minimum of the two pyroxene
absorptions at 1 and 2 um, before and after the continuum removal
respectively.
The analysis was performed using 183 visible and near-infrared spectra
taken from the literature for 115 V-type asteroids. The asteroids were
grouped according to their dynamical properties and their computed
spectral parameters compared. A comparison was also performed with
spectral parameters of a sample of HED meteorites taken from the RELAB
database, and with data from the Dawn mission to Vesta.
Our analysis shows that although most of the V-types in the inner Main
Belt do have a surface composition compatible with an origin from Vesta,
this seems not to be the case for most of the NEAs and the middle and
outer Main Belt V-types. These results must be confirmed using a larger
sample, but it is the first time that these diversities are clearly shown.

Gravitationally lensed quasars can be used to measure cosmological distances and study quasars and their host galaxies at z~2, as well as Dark Matter (DM) in massive galaxies at z~1. However, they are as valuable as they are rare, and sufficient ancillary data are needed. I will illustrate current efforts in collecting more data for existing systems and discovering more systems in wide-field surveys, mainly in the Southern Hemisphere. I will show the science that results from follow-up on time-variability, spectroscopy and high-resolution imaging, with an eye to current and upcoming ESO observational facilities.
The second part of the talk will be devoted to a different study of DM in massive galaxies, based on the dynamics and chemistry of their extended populations of Globular Clusters and Planetary Nebulae. Starting from previous work on M87, I will then discuss the progress on two other `nearby' systems from work with ESO collaborators.

Although observations of galaxies and cosmological simulations have the common goal of trying to understand galaxy evolution, in practice there exists a wide gap between observers and theorists. I will introduce the Millennium Run Observatory project, which aims to narrow this gap by forward-modeling of cosmological simulations in a virtual theoretical observatory. I will show several applications related to the evolution of galaxies and clusters and new surveys.

We present the star-formation histories (SFHs) of a set of dwarf galaxies of the Local Group. These galaxies have been observed with ACS@HST reaching the oldest main-sequence turn-offs with the aim to study from the onset of the star formation to the present time. To obtain the SFHs we have used IAC- star/IAC-pop/Minniac algorithms which have been developed to obtain the best age and metallicity resolution from the observations. The accuracy of the observations and the method used allow us to obtain insights about processes in the early Universe, such as Reionization or SNe feedback effects. The unprecedented age resolution obtained for the stellar populations of these galaxies allow us to cast some light also in the mass-metallicity relation observed both in the local Universe and at high redshift.

The discovery of distinct sub-populations in Galactic globular clusters is one of the most important and intriguing achievements of stellar astrophysics research. We briefly discuss the most important observational evidence of the multiple stellar population phenomenon, and review the most recent empirical results in this context. The theoretical evolutionary scenario needed in order to fully interpret the various observational results is discussed in some detail.

I will discuss the very classic topic on the formation and evolution of molecular gas and molecular clouds in nearby spiral galaxies including the MW. I will focus on two key topics on the evolution of the gas that leads to star formation: (1) the HI and H2 phase balance and evolution during a galactic rotation, and (2) the development of dense clumps within molecular gas during a spiral arm passage. The classic/textbook scenario of ISM evolution ties the gas phase evolution and star formation, positing a rapid gas phase transition from interarm HI, to giant molecular clouds (GMCs) and star formation in a spiral arm, and then back into HI by photodissociation. This HI-H2 phase transition, however, is observed only at the outskirts of galaxies, but not in their major inner parts. Instead, the gas resides largely in GMCs even in interarm regions, but stays inactive in star formation. Therefore, the mere presence of GMCs is not sufficient for star formation, and star formation must be triggered in pre-existing GMCs. I will also show evidence for the development of dense molecular clumps, the precursor of star formation, predominantly in molecular gas in spiral arms. This last part of work is done in collaboration with Tsuyoshi Sawada (JAO) and Tetsuo Hasegawa (NAOJ Chile).

Quasars are active extragalactic sources whose emission is powered by
accretion of material onto a central black hole. Thanks to their
intrinsic high luminosities, they are unique probes of the early
Universe (z>5.5, i.e., <1 Gyr from the Big Bang), at the end of the
epoch of reionization. In this talk, I will present the most up-to-date
results of the z~6 quasar search using the Pan-STARRS1 Survey and I will
briefly introduce our on-going multi-wavelength follow-up efforts to
characterize them. In particular, I will focus on the study of the
galactic environment of a z~5.7 quasar, through deep, broad and narrow
band imaging with FORS2 at the VLT. We test the presence of the
theoretically predicted overdensity of galaxies, searching for Lyman
Alpha Emitters (LAEs). We do not find an enhancement of LAEs in the quasar
field. I will discuss here this result and possible interpretation. Our
multi-wavelength campaign will provide us with a unique insight on the
dawn of the observable universe.

Very often we want to assess the if there is a correlation between two quantities. This is often done in the frequentist framework, using p-value analysis; unfortunately, it has been demonstrated that there are some fundamental flaws behind this kind of null hypothesis testing procedure.
We consider the alternative approach of applying the Bayesian framework. To do so, we estimate the probability distribution of the parameter of interest, $\rho$, characterizing the strength of the correlation. We provide an implementation of these ideas and concepts using python programming language and the pyMC module in a very short (~130 lines of code, heavily commented) and user-friendly program. We used this tool to assess the presence and properties of the correlation between planetary surface gravity and stellar activity level as measured by the log(R'_HK) indicator. The results of the Bayesian analysis are qualitatively similar to those obtained via p-value analysis, and support the presence of a correlation in the data. The results are more robust in their derivation and more informative, revealing interesting features such as asymmetric posterior distributions or markedly different credible intervals, and allowing for a deeper exploration.
We encourage those interested in this kind of problem to apply our code to his/her own scientific problems. The full understanding of what the Bayesian framework is can only be gained through the insight that comes by handling priors, assessing the convergence of Monte Carlo runs, and a multitude of other practical problems. We hope to contribute so that Bayesian analysis becomes a tool in the toolkit of researchers, and they understand by experience its advantages and limitations.

During two weeks of intense work the participants will have the chance to have hands-on real-life experience on the full cycle from proposal preparation to data reduction. Participants will be divided in 5 groups of 4. During the whole school, each group will be guided by a tutor and possibly by a tutor assistant. The school is preferentially targeted to PhD students from whole South America, but advanced MSc's and more senior PostDocs can also apply.

After a preparatory work done at the ESO Headquarters in Chile where the students will have lectures on the basics of observing techniques and how to prepare observations for ESO telescopes, the group will go up to the La Silla Observatory for a 3-night of observations in the ESO NTT, 3.6-m and the MPG/ESO 2.2-m telescope. Back in Santiago with the data in hand, the participants will reduce and analyse their datasets.

While having lectures on hot-topics of the present day astrophysics, the teams will prepare their presentation of their results to the ESO audience. Additional training on aspects of career development is also foreseen.

We would like to have an informal discussion concerning the results of the science talks poll at morning coffee.

Wide-field imagers are playing a crucial role in modern astrophysics, nevertheless, most wide-field surveys are performed in white light or broad band filters (with some relevant exceptions). The Observatorio Astrofísico de Javalambre has been designed to carry out the Javalambre Physics of the accelerating universe Astrophysical Survey (J-PAS), which consists of 8,500sq.deg. of the northern extragalactic sky observed in 59 filters with the main aim to detect baryonic acoustic oscillations to be used as cosmological indicators. The photometric calibration will be based on another project (involving 12 filters): the Javalambre Photometry of the Local Universe Survey (J-PLUS). In this talk, I will review the scientific potential of these surveys and emphasise the possibilities opened by OAJ to European astronomy.

The ΛCDM model represents nowadays the best understanding of the formation and the evolution of large scale structures in our Universe. Nevertheless, this paradigm is not predictive and successful yet at smaller scales. In this context, satellites in the Local Group (LG), the simpler and closer galactic systems, are one of our best chance to test this model and to improve our comprehension of galaxy formation at smaller scales. In this talk, I will present a dynamical measurement of the tangential motion of the Andromeda system, the ensemble consisting of the Andromeda Galaxy (M31) and its satellites. The system is modeled as a structure with cosmologically-motivated velocity dispersion and density profiles, and we show that our method works well when tested using the most massive substructures in high-resolution LCDM simulations. Applied to the sample of 40 currently-known galaxies of this system, we find a value for the transverse velocity of ~150 km/s, significantly higher than previous estimates of the proper motion of M31 itself. This result has significant implications on estimates of the mass of the Local Group, as well as on its past and future history.

Elliptical and lenticular galaxies that nowadays reside preferably in clusters and massive groups of galaxies, possess smooth and simple morphology. However, their evolutionary paths are far from being simple. Key evolutionary factors for early-type galaxies are: (a) merger histories including numerous major and minor mergers; (b) gravitational interactions and ram pressure stripping in dense cluster environment; (c) possibly non-standard stellar initial mass function (IMF) that affected stellar feedback in the remote past. Another [often forgotten] phenomenon that affects galaxy evolution in clusters is tidal stripping that might cause the stellar mass loss of up-to 99% and leads to formation of compact stellar systems, compact elliptical (cE or M32-like) and ultra-compact dwarf (UCD) galaxies. I will present some results obtained during the last 8 years on early type galaxy evolution and the IMF, most of which were powered by data archives and the VO. We re-analyzed published data available in archives, derived first radial profiles of stellar populations in dwarf elliptical galaxies and pointed out their similarity to giant elliptical and lenticular galaxies. We re-reduced and re-analyzed archival ESO VLT data and obtained first reliable stellar population parameters for a large sample of UCDs that proved their formation by tidal stripping. We discovered ~95% of all known cE galaxies using VO technologies, confirmed some of them by optical spectroscopy and performed numerical simulations of their formation by tidal stripping; then we demonstrated that 11 isolated cE that we discovered are likely objects that ran away from their host clusters. Using the positional cross-match between wide field surveys from far-UV to near-IR and constructing hundreds of thousands fully corrected galaxy SEDs (a Reference Catalogue of SEDs of galaxies or RCSED), we discovered that the famous tight red sequence of elliptical galaxies in the optical color-magnitude diagram is a tip of a thin surface formed by all non-active galaxies in the 3-dimensional NUV-optical color-color-magnitude space. As one of the most active VO users in the community, I will describe what the "ultimate" data archive should look like in order to facilitate astrophysical research.

Accretion is the process by which most objects in the Universe grow in mass: from young stellar objects still in the star-forming process, through accreting white dwarfs and neutron stars, to stellar-mass black holes and supermassive black holes at the centre of galaxies (active galactic nuclei). Although the importance of accretion has been recognised for many years, the detailed physics is still poorly understood. In this talk I will discuss the already known similarities between accreting compact objects, and present new phenomenological spectral/timing similarities observed across all types of accreting systems, compact or not. The most recent results quantitatively link the observed X-ray variability in accreting black holes to the optical variability of accreting white dwarfs and young-stellar objects. These results suggest a common physical mechanism driving accretion-induced variability across all mass and size scales, irrespective of the accretor type. Although far from perfect, the fluctuating accretion disk model does a reasonably good job at reproducing some of the observed spectral/timing properties, and this will also be discussed in the context of the old and new observations. I will conclude by presenting some future prospects to this field and posing open questions in the context of unifying further the accretion phenomenology of accreting systems on all scales

Stars with more than about ten solar masses dominate galactic ecosystems. Understanding their formation is one of the great challenges of modern astronomy. The spectacular HII regions they excite delineate the spiral arms of galaxies such as our own – making it clear that star formation and Galactic structure are intimately related. We report on an ambitious program that consists of a powerful multi-pronged approach to study star formation over the whole Milky Way. Using VLBI observations of maser sources associated with young protostars, we are measuring distances by trigonometric parallax to most of the dominant star forming regions in the Galaxy, which reveal its spiral structure, yield improved values of the rotation parameters and are crucial for determinations of luminosities and masses. Submillimeter emission from dust surveyed over the whole Southern Galactic plane with the APEX telescope delivers the locations of deeply embedded protostars and protoclusters and their masses. In a comprehensive follow-up program we are studying the state of excitation, chemistry and kinematics of their gaseous content. At longer wavelengths, in a very sensitive survey with the newly expanded Karl G. Jansky Very Large Array (JVLA) we image the radio emission of the whole (northern) Galactic plane and its polarization with ~1 arc second resolution and also find masers and hyper- and ultracompact HII regions, pinpointing the very centers of very early star-forming activity. Moreover, we are studying the infrared emission from more developed massive star clusters, deriving distances with the classic spectro-photometric method adapted to IR data and properly calibrated with radio trigonometric parallaxes. Our synoptic approach is using the world’s premier observatories to create a coherent, unique dataset with true legacy value for a global perspective on star formation in our Galaxy.

The Herschel photometric maps (70-500 micron) of Galactic clouds are the visually most impressive outcome of the Herschel mission. In particular massive star-forming regions show a large diversity in spatial structure (shells, filaments, pillars, and globules) and strong gradients in temperature, caused by the impact of already formed OB-clusters. These radiative feedback processes have a significant influence on the column density structure of molecular clouds, and on the star-formation process. However, turbulence, gravity, and magnetic fields also play an important role, and I will show how the different processes can be disentangled. The ubiquitous presence of filaments in star forming regions is now a commonly accepted reality. However, their link to star formation remains largly unexplored. Molecular line studies showed that filaments actively accrete from their environment and redistribute the material to form prestellar cores/clusters. This dynamic mode of star formation is also put forward by various numerical models. I will present the results of our imaging and molecular line studies of filaments in several high-mass star-forming regions.

The field of exoplanet atmospheres is booming thanks to (low-resolution) space-borne spectrographs and high-resolution (narrow-ranged) NIR spectrographs on ground-based 8m-class telescopes. Atmospheres are important because they are our observing window on the physical, chemical, and evolutionary processes occurring on exoplanets. Transiting exoplanets are the best suitable targets for atmospheric studies. Observing a transit in different filters or with a spectrograph reveals the transmission spectrum of the planet atmosphere. More than one decade of such observations allowed the exploration of these remote words by detecting some constituents of their atmospheres, but revealing also the presence of scattering hazes and clouds in several exoplanets preventing the detection of major chemical constituents at low to medium resolution even from space.

Transit observations from the ground with stabilised high-resolution spectrograph, such HARPS, have key roles to play in this context. Observation of the hot-jupiter HD 189733b with HARPS allow the detection of sodium in the planet atmosphere. The high-resolution transmission spectra allowed to probe a new region high in the atmosphere and revealed rapid winds and a heating thermosphere. This new use of the famous planet hunter turned HARPS into a powerful exoplanet characterisation machine. It has the precision level of the Hubble Space Telescope, albeit at 20 higher resolution.

A survey of a large set of known hot transiting exoplanets with HARPS and later with ESPRESSO will allow the detection of key tracers of atmospheric physics, chemistry, and evolution, above the scattering haze layers known to dominate low-resolution visible spectra of exoplanets.

Such observation, in total sinergy with other technics, will firmly establish stabilised, high-resolution spectrographs on 4m telescopes as corner-stones for the characterisation of exoplanets. This is instrumental considering the upcoming surveys (NGTS,K2, CHEOPS, TESS, PLATO) that will deliver hundreds of exoplanets amenable to atmospheric characterisation.

Around 20 stellar-mass black holes (BHs) have been discovered forming part
of binary systems in the Milky Way and in nearby galaxies. Their spectral
energy distribution and variability at different wavelengths have allowed
to build up a common phenomenological picture. While most of these BH have
been discovered through X-ray emission from the accretion of gas from
their binary companions, recent studies have allowed us to discover the
first of such systems in a quiescent state. I will introduce the topic of
BH in binary systems and focus on this recent discovery, emphasyzing what
we have learned from multi-wavelength studies of this system. I will also
comment on recent research on similar systems containing either BHs or Be
stars that has been possible thanks to this discovery.

Multi-wavelength studies have accurately constrained the growth of galaxies through cosmic time: The rate of star formation per unit of cosmological volume increased from the earliest epochs until z=1-3 (Universe age: 2-6 Gyr), when it peaked (the "epoch of galaxy assembly"), then steeply declined by more than an order of magnitude until z=0 (today). What drives this evolution? I will address this fundamental question by targeting the fuel for star formation, i.e., the dense phase of the interstellar medium. This is possible only now, thanks to technological upgrades and the advent of new facilities, in particular the Atacama Large Millimeter Array. For the first time, observations of the interstellar medium in high-z galaxies can be pushed well beyond the “tip of the iceberg” of extremely luminous galaxies, thus uncovering the bulk of the galaxy population. We can now for the first time directly gauge the molecular gas content of galaxies throughout cosmic time, investigate the interplay of various gas phases (molecular, atomic, ionized) via multiple gas tracers, and constrain the efficiency of star formation in different galaxy types and cosmic epochs. The results of these studies will provide unique constraints on empirical predictions and theoretical models of the physics of the interstellar medium and thus of the evolution of galaxies throughout cosmic time.

The Kepler space telescope has observed hundred of thousands of stars continuously during the four years of the prime mission. It has detected thousands of potential transiting planets up to 1AU and down to the size of the Earth. These detections provide new constraints to the theories of planet formation, migration, and evolution, at a level never reached before. However, transit signals could be mimicked by other, non-planetary scenarios. These other scenarios, the so-called false positives, bias the physical properties of exoplanets derived from the transit detections and thus, they might lead us to wrong conclusions. To secure these planet detections, two main techniques are used: the velocimetric and statistical validation methods. In this seminar, I will first present the astrophysical motivations of finding (transiting) exoplanets and the limitations raised by the presence of false positives. I will then describe the two main solutions I'm using to overcome these limitations. This will be illustrated by the recent results achieved thanks to a 5-year programme with the SOPHIE spectrograph at Observatoire de Haute-Provence (France). This spectroscopic programme allowed us to derive unbiased statistical properties of giant transiting exoplanets within 400 days of period. In this context, I will finally present the on-going observing programmes at ESO telescopes to extend this work towards the new candidates detected by the K2 space mission.

Mass accretion onto supermassive black holes occurs on scales beyond the diffraction limit of any single optical/infrared (IR) telescope. Thanks to the resolution power of the VLT Interferometer, we are now tapping into the outer accretion structure of active galactic nuclei (AGN) — commonly referred to as the “dusty torus”. Several surprising results are challenging our current paradigm: While the bulk of the mid-IR emission originates from perpendicular where models would put the torus, the IR emission as a whole appears to be made of two components. In this talk I will give a basic introduction to IR interferometry and discuss what our recent results tell us about AGN unification and the physical processes that regulate accretion and feedback. I will also give a brief glimpse into how IR interferometry can help us establishing AGN as cosmological distance measures.

Mass accretion onto supermassive black holes occurs on scales beyond the diffraction limit of any single optical/infrared (IR) telescope. Thanks to the resolution power of the VLT Interferometer, we are now tapping into the outer accretion structure of active galactic nuclei (AGN) — commonly referred to as the “dusty torus”. Several surprising results are challenging our current paradigm: While the bulk of the mid-IR emission originates from perpendicular where models would put the torus, the IR emission as a whole appears to be made of two components. In this talk I will give a basic introduction to IR interferometry and discuss what our recent results tell us about AGN unification and the physical processes that regulate accretion and feedback. I will also give a brief glimpse into how IR interferometry can help us establishing AGN as cosmological distance measures.

During fall 2012 the Dark Energy Survey (DES) collaboration installed and commissioned DECam, a 570 mega-pixel optical and near-infrared camera with a large 3 sq. deg. field of view, set at the prime focus of the 4-meter Blanco telescope in CTIO, Chile. Since then, and for a period of five years, DECam has started mapping an entire octant of the southern sky to unprecedented depth, measuring the position on the sky, photometric redshift and shape of over 200 million galaxies, together with thousands of galaxy clusters and supernovae. With this unique data set, DES will study the properties of dark energy using four main probes: galaxy clustering on large scales, weak gravitational lensing, galaxy-cluster abundance, and supernova distances.

In this talk I will review the DES early results on galaxy clustering and weak gravitational lensing using the DES Science Verification (SV) period of observations, which provided science-quality images for about 150 sq. deg. at the nominal depth of the survey. Weak gravitational lensing, the small deflection of light rays from distant galaxies in the presence of an intervening gravitational potential, provides an entirely complimentary method of probing the dark matter distribution to the measurement of angular galaxy clustering. The independent results from both probes will be discussed, including the cosmological analysis of the SV cosmic shear measurement, and new cosmological results from the combination of galaxy clustering and galaxy-galaxy lensing, capable of obtaining cosmological constraints by separating the clustering of galaxies from that of the underlying dark matter distribution through the measurement of galaxy bias, will be presented.

I will present the discovery of a super-Chandrasekhar double-degenerate binary system at the heart of the planetary nebula Hen 2-428.  Planetary nebulae (PNe) represent the final stage in the evolution of low- and intermediate-mass stars, forming from the mass ejected by the star during its AGB evolution before being ionised by the star's, now exposed, core.  As binarity is expected to play a key role in the formation of aspherical PN morphologies, we have been intensively searching for new binary central stars in a push towards a statistical sample.  One of our newly-discovered binary systems had a further surprise to reveal, with observations and modelling showing the system to consist of twin evolved stars with a total mass greater than the Chandrasekhar limit.  The short period of the system, only 4.2 hours, means that the two stars will merge together in approximately 700 Myr, resulting in a Supernova Type Ia.  While the super-Chandrasekhar merger of two white dwarfs has long been considered a formation pathway for SN Ia, this is the first system found that is confirmed to be both massive enough and in a tight enough orbit to merge in less than a Hubble time.