Seminars and Colloquia at ESO Garching and on the campus

In my talk I will first briefly review the application of galaxy clusters as tools to trace cosmic evolution. I will then discuss the recent advances in the this field, as driven by the increasing quality of observational data, and by the much improved description of clusters through detailed numerical simulations. In this context I will present recent results on the analysis of such simulations aimed at calibrating clusters as precision tools for cosmology. Finally, I will highlight the potential that future large surveys of galaxy clusters could have to trace the growth of cosmic structures and to shed light on the constituents of the Universe and the nature of primordial perturbations.

We will report on the science highlights from the conference "The first year of ALMA science", held on Dec 12-15 in Puerto Varas. On Dec 19, Leonardo Testi will discuss galactic science topics: astrochemistry, Solar System, star and planet formation and stellar evolution. Extragalactic topics will be covered by Paola Andreani on January 9.

We will demonstrate how to use the new email security solution, i.e. how to check your spam quarantine, how to release emails from the spam quarantine, how to create your personal blocklist/safelist. What is actually spam and where does it come from? We will also explain who the spammers are, what their motivation is and what the risks are for you. Did you know that we filter up to 99% of all incoming emails as spam or infected emails? We will give you some insight how spam filtering at ESO works and what the challenges are.

Filamentary structure has long been recognized as the dominant morphology in the interstellar medium (ISM). Recently, near-IR and far-IR surveys carried out by Spitzer and Herschel have revealed a large population of dust filaments in our Galaxy. The prevalence of filaments in the ISM triggered a renewed interest on their formation, evolution, and especially their role in star formation. I review recent discoveries with an emphasis on observations, following a tentative classification: Filaments (FL), Hub-Filament Systems (HFS), and Filamentary Networks (FNET). We will discuss further directions of this relatively new topic.

A decade of exoplanet search has led to surprising discoveries, from giant planets close to their star, to planets orbiting two stars, all the way to the first extremely hot, rocky worlds with potentially permanent lava on their surfaces due to the star's proximity. Observing mass and radius alone can not break the degeneracy of a planet's nature due to the effect of an extended atmosphere that can also block the stellar light and increase the observed planetary radius significantly. Even if a unique solution would exist, planets with similar density, like Earth and Venus, present very different planetary environments in terms of habitable conditions. Therefore the question refocuses on atmospheric features to characterize a planetary environment and what the spectra of an exoplanet can reveal.

Recent observational studies have shown that the most massive galaxies in the Universe, brightest cluster galaxies (BCGs), are almost fully assembled in terms of their stellar mass half way back to the big bang. This observation is in contrast to the predictions of current cosmological models which suggest that BCGs should more than double their stellar mass over this time. A recent study (Tonini et al., 2012) aimed to reconcile the observations and theory by predicting the stellar masses of BCGs using more up-to-date stellar population synthesis models. I will discuss the strengths of their approach, compare their results to our recently acquired BCG colours at z~1 and discuss the implications for our current understanding of hierarchical evolution in dense environments.

I review some recent developments in attempting to reconcile the observed galaxy population with numerical models of structure formation in the 'LCDM' concordance cosmology. Focussing on behaviour of dwarf galaxies, I describe the infamous 'cusp-core' dichotomy - a long-standing challenge to the LCDM picture on small scales - and use toy models to show how it is resolved in recent numerical simulations (Pontzen & Governato 2012). I then discuss the current observational status of this picture (Teyssier, Pontzen & Read 2012; Penarrubia et al 2012). In the second half of the talk, I apply the analytic techniques developed for probing the effect of gas on dark matter dynamics to the question of how, in the absence of baryons, a universal "NFW" dark matter halo profile emerges (independent of scale or details of the initial conditions). Thus the generation of NFW halos on the one hand and the destruction of their central cusps on the other can be ascribed to surprisingly similar physical arguments.

I will talk about two different aspects of massive galaxy evolution. First, I will discuss the assembly of elliptical galaxies based on high signal to noise spectra beyond the effective radius taken with an integral-field spectrograph. The stars in the outskirts of these galaxies are enriched in alpha elements but have low metallicity, similar to thick disk stars in our galaxy. We suggest that these stars were accreted from small galaxies that formed early and had a truncated star formation history. Second, I will discuss supermassive black hole scaling relations, and what they may tell us about the coevolution of black holes and galaxies. I will end with tantalizing new clues about the lifetimes of sub-pc supermassive black hole binaries.

The origin of the gas in local early-type galaxies, and its relative dearth compared to stellar evolution expectations, are long standing issues. Gas reservoirs should be regenerated as stars lose mass, however sensitive searches find molecular gas in only 22% of local early-type galaxies. Furthermore these studies find that the amount of gas present does not correlate with the amount of stars losing mass in a given galaxy. Mergers and cold accretion provide an alternative way to introduce cold gas to a galaxy. Measurement of the kinematic misalignment between gas and the stars can be used to constrain the importance of these internal and external processes, allowing us to begin to understand the gas supply gas to ETGs. Using this technique I have shown that external sources seem to dominate, at least in field galaxies. In this informal discussion I will quickly review these findings, and then go on to highlight a major outstanding problem in understanding the distribution of kinematic misalignment angles in nearby ETGs. Simple mathematical arguments, and analytic simulations show that gas must be destroyed far quicker than it can be used up through star-formation (and the minor merger/accretion rate must be higher than previously estimated) in order to reproduce the observed distributions. The only alternative is that gas does not relax into galaxy disks at the rates typically assumed in the literature.

A major uncertainty in models for photoionised outflows in AGN is the distance of the gas to the central black hole. We present the results of a massive multiwavelength monitoring campaign on the bright Seyfert 1 galaxy Mrk 509 to constrain the location of the outflow components dominating the soft X-ray band. Mrk 509 was monitored by XMM-Newton, Integral, Chandra, HST/COS and Swift in 2009. We have studied the response of the photoionised gas to the changes in the ionising flux produced by the central regions. We were able to put tight constraints on the variability of the absorbers from day to year time scales. This allowed us to develop a model for the time-dependent photoionisation in this source. We find that the more highly ionised gas producing most X-ray line opacity is at least 5 pc away from the core; upper limits to the distance of various absorbing components range between 20 pc up to a few kpc. The more lowly ionised gas producing most UV line opacity is at least 100 pc away from the nucleus. These results point to an origin of the dominant, slow (v < 1000 km/s) outflow components in the NLR or torus-region of Mrk 509. We find that while the kinetic luminosity of the outflow is small, the mass carried away is likely larger than the 0.5 Solar mass per year accreting onto the black hole. We also determined the chemical composition of the outflow as well as valuable constraints on the different emission regions. We find for instance that the resolved component of the Fe-K line originates from a region 40-1000 gravitational radii from the black hole, and that the soft excess is produced by Comptonisation in a warm (0.2-1 keV), optically thick (tau~10-20) corona near the inner part of the disk.

The colonization of the continents by land plants over 450 million years was one of the most far-reaching chapters in the history of life on Earth. It fundamentally changed the ecology and climate of the planet. In this talk, I will discuss how new findings are supporting the exciting long-standing hypothesis that symbiotic relationships between early land plants and soil-dwelling fungi fuelled the ‘greening of the Earth’, and how by relentlessly burning fossil photosynthesis we are threatening to destabilize the climate system with potentially disastrous impacts for future generations and nature. Given that astronomers will eventually be able to diagnose the composition and state of the atmospheres of planets in the 'habitable zone', I will outline some of the atmospheric changes that might be expected to relate to plant evolution.

Stars more massive than about 1.5 M_sun lack a significant convective envelope that is a key ingredient in driving a solar-like dynamo. Despite this fact, there is a small population of chemically peculiar, intermediate-mass A- and B-type stars that have been known to host strong, globally-organized magnetic fields for over half a century. Furthermore, in the last decade our knowledge of magnetism has extended to more massive stars with the detection and characterization of the large-scale magnetic fields in a few O-type stars. In this talk I will briefly review the history of our knowledge of magnetism in stars more massive than ~1.5 M_sun. I will discuss the theory and techniques we use to measure these fields and summarize the current state of our knowledge. Finally, I will the discuss the interesting consequences of these strong magnetic fields on the photospheric structure and its interaction with the radiatively driven outflows for these stars.

It is now almost certain that at the center of our Milky Way Galaxy lies a super massive black hole - 4 million times more massive than our Sun. Because of its proximity to Earth, this object, known as Sagittarius A*, presents astronomers with the best opportunity in the Universe to spatially resolve and image a black hole Event Horizon. To do this requires using Very Long Baseline Interferometry (VLBI), the technique whereby radio telescopes around the world are linked together in a Global phased array. Very short wavelength VLBI observations have now confirmed structure on ~4 Schwarzschild radius scales within SgrA*, and have revealed time variability in this source on the same spatial scales. For the much more massive (6 billion solar mass) black hole powering the relativistic jet in M87, similarly compact structures have been detected. I will describe the instrumentation efforts that enable these observations, discuss what current and future VLBI observations can tell us about these super-massive black holes, and describe plans for assembling a Global submm-VLBI Event Horizon Telescope.

I will introduce the use of chromospheric spectroscopic indicators in solar-type stars as a tool to investigate their magnetic activity. Then I will focus on the calibration of chromospheric fluxes as a means to obtain stellar ages, and discuss briefly their usefulness and limitations. Finally I will present a brand-new calibration based on the infrared Ca II triplet which we think enables the dating of old stars reliably.

We briefly introduce the historical developments concerning the estimates of the age of the Universe. Then, we will focus our attention on the most popular methods adopted to estimate the age of stellar systems (clusters, globulars). Finally, we will mention some possible avenues based on deep and accurate near-infrared color-magnitude diagrams (in other words, in the E-ELT era).

Circumstellar discs in young stars provide the raw material - gas and dust - for planet formation; discs also effect the radial re-distribution of planets and thus play a major role in shaping planetary architecture. Understanding the interplay between discs and planet formation and migration therefore requires a good understanding of how discs evolve and how they are dispersed. Currently, however, it is still debated whether discs are self-consumed through planet formation or whether planet formation occurs in competition with some other agent for disc dispersal. Much of this talk is devoted to new work that shows how the photoevaporation of gas from such discs by Xrays from the central star is an important agent for disc dispersal. The talk gives an overview of the disc properties that can be deduced from multi-wavelength data, increasingly supplemented by imaging, showing that our now good statistical knowledge of various stages of disc clearing is largely thanks to large scale surveys conducted in recent years by the Spitzer Space Telescope. I will briefly discuss the several candidate disc clearance mechanisms and then describe the theory of Xray photoevaporation in more detail, including also some observational signatures and possible discriminants. I conclude with a description of the bewildering zoo of "transition discs" (i.e. discs with cleared inner regions) and discuss the extent to which they can be understood in terms of clearing by photoevaporation / planet formation.

I will give some basics of how cosmological galaxy formation semi-analytic models work and why and when they are useful. I will focus on the recent developments on how to model star formation in the large scales (~kpc), motivated by theory and observations, and the impact such modelling can have on galaxy properties. If there is time, I will also mention how multi-phase ISM modelling can naturally lead to the application of more sophisticated theoretical models of feedback in galaxies.

Recent spectroscopic and photometric observations have revealed that massive stellar clusters are not made of a single stellar population but rather host multiple populations. Also, they should have been produced within very extensive episodes of star formation, which involved much more stars than currently present in the globular clusters. I will review the evidences for multiple populations in globular clusters and explore some of its implications on their formation and early history. I will also comment on the relation between the formation of the globular clusters and that of the galactic halo, and implicitly of all stellar populations characterized by a high relative frequency of globular clusters.

During the last decade, high precision photometric and spectroscopic observations have brought evidence for the presence of multiple stellar populations in globular clusters, refuting the idea that these systems are composed out of single stellar populations in which all stars have the same chemical composition and age. In particular, stars in globular clusters show a significant spread in light-medal abundances and an anti-correlation between Na and O, and Mg and Al. Since these anti-correlations are not observed among field halo stars that are believed to have formed together with the globular clusters, they raise important questions concerning the origin of globular clusters and the link between them and dwarf galaxies. In my discussion, I will present the different ideas that have been put forward to explain the light element abundance patterns and discuss future observations which might help to decide where they come from.

I will argue that observations of the diffuse gas in the outskirts of galaxies, the so called circumgalactic medium, are essential for constraining the 'initial conditions' for galaxy formation. Such observations provide a fruitful comparison to theory, because hydrodynamics at moderate overdensities is much easier to simulate than molecule or star-formation. A novel technique will be introduced, whereby a foreground quasar (and massive galaxy) can be studied in absorption against a background quasar, resolving scales as small as 30kpc. This experiment reveals a rich absorption spectrum which contains a wealth of information about the physical conditions of diffuse gas around massive proto-galaxies. I will summarize the implications of these new measurements in the context of galaxy formation models, and also discuss a sensitive search for emission from the same gas we study in absorption.

- Eric Emsellem : SpS3 Galaxy Evolution through Secular Processes / - Davor Krajnovic : IAUS295: The intriguing life of massive galaxies / - Tim Davis : Extragalactic part of IAUS292 Molecular Gas, Dust, and Star Formation in Galaxies; JD4, UV Emission in Early-Type Galaxies / - Steve Longmore : Galactic part of IAUS292; SpS8, Calibration of SFR Measurements; Sp12, Modern Views of the ISM

- Francesca Primas : WAM Women in Astronomy Meeting / - Nadine Neumayer : SpS1, Origin and Complexity of Massive Star Clusters / - Michael Hilker : SpS1, Origin and Complexity of Massive Star Clusters / - Felix Stoehr : SpS15, Data Intensive Astronomy

Spectropolarimetric techniques have been successfully employed in stellar physics for almost two decades. I will discuss the basics of magnetic field measurements, as well as the advantages and limitations of a few methods currently used. I will conclude by presenting the contribution of spectropolarimetric measurements to the study of magnetism of low-mass stars.

We are presently studying in great detail NGC 5253, a peculiar and nearby Blue Compact Dwarf galaxy, with the general aim of gaining insight on the processes that take place in the interplay of massive star formation and the surrounding gas. An open issue not addressed so far is how collisional and radiative transfer effects affect the determination of He^+ abundance. In this informal discussion I will i) summarize the results that we have obtained so far for the galaxy, emphasizing those that might be relevant for this particular issue; ii) explain how I became aware of it, how collisional and radiative transfer effects affect the HeI emission lines and why paying attention to them is important in the context of extragalactic astronomy; iii) discuss the 2D characterization of these two effects in NGC 5253.

With the use of high-performance coronagraphs, quasi-static speckles limit our ability to image faint companions next to bright stars, e.g. extrasolar planets. Electric field conjugation (EFC), also called speckle nulling, is a method that uses a deformable mirror to annihilate these speckles during observation, working in principle quite similar to adaptive optics. I will review the physical background of quasi-static speckles and this technique, as well as requirements on instrumentation. I will continue presenting EFC experiments performed at ESO and at UJF Grenoble in preparation for EPICS, the E-ELT planet finder.

Parameterizing light profiles of galaxies with a Sersic (1968) function and decomposing them into multiple sub-components is a popular method of estimating parameters and inferring the assembly history of galaxies. It is being routinely applied on the nearby objects, most distant galaxies and samples of several thousands (and millions) of objects. The method, however, is technically not trivial, and, while there are free software solutions, it is generally difficult to compare results of different studies. It is also a source of a major confusion in extra-galactic astronomy. I will outline the main points of the decomposition techniques as a stimulus for a discussion on three specific topics: how to do it (i.e. is there the best way), on what objects should it be applied (i.e. is it necessary), and what is the meaning of the sub-components (i.e what do we learn)? And I am very interested to hear your views. Finally, I will present some of the results obtained when decomposing early-type galaxies (in one of the possible ways) from a magnitude limited sample and comparing these to their kinematic properties. The main conclusion are: (i) ~80-85% of nearby early-type galaxies (without bars) show evidence for having two components of which at least one is exponential (disc), and (ii) photometric decomposition, can be used as a guide line, but not as a substitute for kinematics.

The morphology of disk galaxies is characterized by the presence of spirals and bars. Such structures have been considered as the result of dynamical mechanisms associated with ordered stellar and gaseous flows acting on the disks. However, in the last years the contribution of chaotic motions in the reinforcement of barred and spiral structures has been emphasized. I will review the new dynamical phenomena that have been found to play an important role for obtaining the observed morphologies of galactic disks in terms of the orbital theory. Chaotic phenomena in the phase space of rotating disks are in many cases essential for modeling the observed features of the galaxies.

A growing number of recent papers claim that the stellar initial mass function (IMF) is not universal among early-type galaxies. There are two broad camps of support: one from the stellar population community that finds evidence in spectral lines for large numbers of low-mass stars; and one from the stellar dynamics side which finds systematically varying amounts of mass apparently unaccounted for by the stellar light using a fixed IMF. I will present an informal discussion on the path we took to get to our recent contribution on this topic using the ATLAS3D Survey, and how our result differs from previous claims.

Neutral hydrogen gas (HI) is an important component of galaxy evolution studies. Unfortunately, due to the limitations of current radio telescopes, the HI universe beyond z=0 will largely remain elusive until facilities such as ASKAP and the SKA become available. However, spectral stacking is a promising technique for pushing the redshift boundary of 21cm detections. I will discuss a stacking analysis of data from the Parkes radio telescope, combined with information from the optical 2dF Galaxy Redshift Survey. By combining the HI signal of thousands of galaxies, we can achieve a strong statistical detection and therefore explore the HI properties of galaxies out to z=0.14.

Recent years have witnessed a flurry of studies that have emphasized the important role that dust plays in our understanding of the near and distant Universe. The short time-scales required for dust enrichment make core-collapse supernovae rather natural candidates for dust producers in the early Universe. Yet, direct evidence that grains condense in such supernovae is extremely sparse. I will discuss lessons learnt from mid-IR studies of supernovae, highlighting problem areas and unexpected findings.

Intervening structures in the universe give rise to small distortions in the shapes of distant galaxies. By measuring this tiny coherent signal, we can study the mass distribution in the universe directly, without relying on baryonic tracers. This makes weak lensing by large-scale structures a powerful probe of cosmology. It allows us to differentiate between dark energy models or modifications of the law of gravity. I will briefly review the topic of cosmic shear and discuss how the signal is extracted from the data and present results from the recently completed analysis of the CFHT Legacy Survey.

For early-type galaxies, the ability to sustain a corona of hot, X-ray emitting gas could have played a key role in quenching their star-formation history. A halo of hot gas may act as an effective shield against the acquisition of cold gas and can quickly absorb stellar-mass loss material. Yet, since the discovery by the Einstein observatory of such X-ray halos around early-type galaxies, the precise amount of hot gas around these galaxies still remains a matter of debate. By combining the homogeneously-derived photometric and kinematic measurements for the 260 early-type galaxies of the Atlas3D integral-field spectroscopic survey with both low- and high-spatial resolution X-ray measurements, I will show that the ability to retain an halo of hot gas depends not only on galactic mass but crucially also on the dynamical structure and intrinsic flattening of a galaxy. Specifically, in the framework of the revised classification for early-type galaxies advanced by the SAURON survey, we found that: 1) Slow Rotators have hot-gas halos with X-ray luminosity and temperature values that are entirely consistent with what expected if the hot gas originates from stellar-mass loss material that is heated up at the kinetic temperature of the stars through shocks and collisions. 2) Fast Rotators have hot-gas halos with X-ray luminosities that always fall short of such a prediction, and the more so the lower their dynamical mass and the larger their intrinsic flattening and degree of rotation support.

Laser frequency combs are the new technology for top precision metrology. They can be also coupled to a spectrograph and serve as calibrators for high precision spectroscopy, from atomic and molecular spectroscopy in the laboratory to spectroscopy of celestial objects. The precision achievable in astronomical spectroscopy assisted by laser frequency combs gives the possibility to address various scientific questions from the field of exoplanets to stellar physics to cosmology. I will describe how a laser comb for astronomy works, the advantages with respect to more traditional calibration methods, and the way such a device can be coupled to an astronomical spectrograph. In particular I will describe what we are learning from our tests of the laser frequency comb on HARPS.

At all redshifts the vast majority of star forming galaxies follow a tight correlation between the star formation rate (SFR) and the stellar mass, which then came to be called the "Main Sequence of star forming galaxies". Yet, outliers exist on both sides of this Main Sequence, with passively evolving (such as elliptical) galaxies below it and 'starburst' galaxies above it. Only recently, thanks to Herschel observations, it has been possible to quantify the relative frequency of MS "liers" and outliers, as well as their relative contribution to the global SFR density at redshift ~2, the cosmic peak in the star formation activity. These evidences and developments will be informally presented and proposed to discussion.

During my visit to ESO I have been engaged in a number of collaborations to try and better understand the physical conditions of dust and gas in star-forming regions. Despite being ongoing research, and thus not yet subjected to rigorous refereeing, two of these projects weave together well for an informal discussion. I will first discuss an investigation into the extinction and emission properties of dust in the Perseus Molecular Cloud, combining Herschel and 2MASS data. I will follow with a theoretical discussion of the time variability of protostellar envelope spectral energy distributions due to episodic accretion events and why long-term monitoring of protostars in the sub-mm should be undertaken.

The Galactic bulge is the only bulge that can be resolved in stars down to the bottom of the main sequence, and for which detailed chemical abundances can be obtained for individual stars. Yet its 3D structure and stellar population is surprisingly poorly understood, mainly due to the lack of wide area surveys. What was believed to be a triaxial spheroid (the bar) is in fact an X-shaped structure. The common practice to extrapolate to the whole bulge the stellar population characteristics of a few low reddening windows, turned out to be very dangerous. I will summarize our current understanding of the galactic bulge, together with ongoing and future efforts to shed light on its origin.

Debris disks are dusty disks orbiting mature stars. They owe their origin to collisional replenishment by small bodies and as such represent a major piece in the unfolding story of the nature of planetary systems. After their discovery by IRAS in 1982, their rich and diverse diagnostics have been studied by major ground-based facilities (VLT, VLTI, and, recently, ALMA) and space missions (HST, ISO, Spitzer). The role of Herschel is to offer for the first time the possibility to study their properties in the main domain in which they radiate their thermal energy, at an appreciable spatial resolution. Building on the important censuses Spitzer has achieved, Herschel has uncovered the anticipated existence of cold debris disks. We will discuss in detail the major results Herschel has achieved on nearby debris disks that can be well resolved spatially, in particular those of Vega, Beta Pictoris and Fomalhaut.

I will review where we detect water in our solar system, how we do this, and why we are interested. I'll go on to talk about where else we expect to see it, and where the current limitations in our detection ability are. I'd like this discussion to concentrate on these problems to be solved, given the wide range of expertise in different techniques and different wavelengths that exists at ESO.

In response to the quantity of exoplanet discoveries in the last 20 years the focus of exoplanet research has shifted from the detection towards the characterization of these planets and, in particular, their atmospheres. Currently, observations of exoplanet atmospheres are mainly feasible for highly inflated giant planets. I will discuss the method of spectrophotometric transit observations, which is currently used to probe such hot Jupiter atmospheres, and point out its successes and limitations. Furthermore I will discuss a project using Earth spectra obtained with the ESA spacecraft Venus Express, in which we aim to investigate the nature of the spectral variability that could potentially be observable for an Earth-like exoplanet with future instrumentation.

The most characteristic property of active galaxies, including quasars, are prominent broad emission lines. These lines allowed to discover the cosmological nature of quasars, and at present they provide the most convenient method of weighting black holes residing in their nuclei. However, a question remains why such strong lines form there in the first place. I will discuss an interesting possibility that dust is responsible for this phenomenon. The dust is known to be present in quasars in the form of a dusty/molecular torus which results in complexity of the appearance of active galaxies. However, this dust is located further from the black hole than the Broad Line Region. We propose that the dust is present also closer in and it is actually responsible for formation of the broad emission lines. The argument is based on determination of the temperature of the disk atmosphere underlying the Broad Line Region: it is close to 1000 K independently from the black hole mass and accretion rate of the object. The mechanism is simple and universal but leads to a considerable complexity of the active nucleus surrounding. I will conclude with the discussion how this idea fits into the general scheme of the quasar structure.

Spectro-astrometry is a powerful technique which can be used to recover spatial information from ground-based spectra on milli-arcsecond scales. In my talk I will describe the technique and outline how to optimise spectroscopic observations for spectro-astrometric analysis. In addition, I will describe how it has been used very successfully to study binarity, outflow activity and the circumstellar environment of young stars and brown dwarfs.

Sparse aperture masking (SAM) interferometry combined with Adaptive Optics (AO) is a technique that is uniquely suited to investigate structures near the diffraction limit of large telescopes. The strengths of the technique are a robust calibration of the Point Spread Function (PSF) while maintaining a relatively high dynamic range. In this talk I will present the main characteristics of this technique, their advantages and limitations, as well as, some targets of opportunity. I will conclude the talk with the preliminary results of our SAM+AO observations on sources in the central parsec of the Galaxy.

The Stratospheric Observatory for Far-Infrared Astronomy (SOFIA) has performed the first successful science flights last year. After the shutdown of the Kuiper airborne observatory (KAO) in 1995, it is now SOFIA that took over and produces science. I will review the properties of the KAO and SOFIA from a personal perspective (I flew with the KAO and had an observing program with SOFIA), and lay out which science can be done with SOFIA, giving practical advice for proposal preparation and background information. I will also present first results of my CII spectral line mapping program that studied pillars and globules in Cygnus and my study on the atmospheric transmission in the submm-FIR range relevant for SOFIA.

In addition to the major planets, the solar system contains a large number of so-called small bodies in dynamically distinct reservoirs. These include the main-belt asteroids, main-belt comets, Trojans, Centaurs, irregular satellites, the comets of the Oort cloud and Kuiper belt, and others. These reservoirs are important both for the relics of solar system formation contained therein, and as sources for short-lived populations in the inner solar system. For the most part, the small body populations were discovered recently, their investigation is still firmly in the exploration phase and much of the excitement in planetary science stems directly from them. I will use new observations of three "freak" and very surprising objects as a vehicle to discuss the small body populations, to highlight our ignorance of even basic issues in the origin and evolution of the solar system, and to indicate potentially productive paths to future research.

I will discuss how photometric and spectroscopic properties of massive globular clusters can help to unveil the formation history of galaxies, since their properties (age, metallicity, structural parameter distributions) reflect the physical conditions at the time of their formation. However, there are key features in their stellar populations which can render even spectroscopic ages younger. I will discuss how these degeneracies can be avoided for a sample of massive clusters in dwarf irregular galaxies and intermediate-age merger-remnant massive galaxies, to unveil the complex merging history of the latter.

Black holes, resident in the centers of galaxies, will be fed by accretion of ambient gas whenever gas reaches those central regions. This can be due to mergers, but even without mergers the evolution of the stellar populations of normal galaxies provides very large amounts of gas, as stars pass through the planetary nebula stage, the total mass release being greater than 10$^{11}$ Msolar for massive ellipticals. Much of that gas will cool and fall to the centers of the systems, where it will induce starbursts and accretion events onto the central black holes. Accretion then induces outbursts of UV from the BH discs, Xrays from coronal gas and polar, radiation driven winds, with the efficiencies in these three categories roughly 10$^{-1}$, 10$^{-2}$ and 10$^{-3}$. The mass, momentum and energy in these outbursts can have dramatic consequences for the growth of the BH and for the ambient galaxy. Most AGN feedback treatments do not include the mass and momentum components. We follow these events with 1D, 2D and 3D hydrodynamic codes. BH growth is similar to what has been found by others, but the momentum driving produces much more energetic winds than does thermal feedback. Observable consequences include the narrow line AGN absorption lines, shock accelerated synchrotron emitting particles and wind driven bubbles in the IGM. In addition, we find that the feedback strongly inhibits inflow, causing episodic accretion and a low "duty cycle". The simulations help us to understand many phenomena including the black hole stellar mass relation, the paucity of gas in ellipticals, the incidence of the ¡°E+A¡± phenomena and the observed fact that most of the black holes found in galactic centers are found in the "off" state.

I will try to describe the main ingredients which lead to the formation of a bar. This will involve some ugly drawings illustrating the basics of density wave theory, physics of resonant cavities, and orbital structure. My (naive) hope is that you walk away with an intuitive view of how bars form, their impact on the evolution of galaxies, and why they are so captivating objects to work on.

Thermonuclear explosions of white dwarfs are thought to explain Type Ia supernovae (SNe Ia) -- but it is still unclear how these explosions come about and how they proceed in detail. This is a fundamental problem as SNe Ia are key players in many fields of astrophysics including galactic chemical evolution and observational cosmology. Since their progenitors elude observation as well as modeling, I will argue that simulations of explosions arising from different scenarios can help to overcome the problem. A new generation of three-dimensional hydrodynamic explosion simulations in combination with radiative transfer calculations allows us to predict observables that can be directly compared to astronomical data. Avoiding tunable parameters in the models, conclusions on progenitor properties are possible. Contradicting 'textbook wisdom', recent results demonstrated that a normal SN Ia does not necessarily require the explosion of a Chandrasekhar-mass white dwarf, but they also do not rule out this possibility. While the question of the progenitor channel responsible for the bulk of objects remains open, the synthesis of modeling and recent observations underpins the emerging picture of SNe Ia being much less homogeneous than previously thought. This could complicate their use as cosmic distance indicators.

[from a paper by N.R.Napolitano, S.Capozziello, A.J.Romanowsky, M.Capaccioli, C.Tortora] The discussion is about the first analysis of the extended stellar kinematics of ETGs made using, as an alternative to dark matter, a Yukawa-like correction to the Newtonian gravitational potential derived from f(R) gravity. In this framework, long-slit and planetary nebulae data for three ETGs with either decreasing or flat velocity dispersion profiles are modeled out to 7 effective radii. The modified Newtonian potential, used in a dispersion-kurtosis Jeans analysis to account for the mass-anisotropy degeneracy, is able to fit well all the data, and produces an anisotropy distribution which is consistent with that estimated if a dark halo is considered. The parameter measuring the "strength" of the Yukawa-like correction is, on average, smaller than the one previously found in spiral galaxies and correlates both with the scale length of the Yukawa-like term and the orbital anisotropy.

Measurements of stellar orbits provide compelling evidence that the compact radio source Sagittarius A* at the Galactic Centre is a black hole four million times the mass of the Sun. With the exception of modest X-ray and infrared flares Sgr A* is surprisingly faint, suggesting that the accretion rate currently is very low. In 2011 we discovered a dense gas cloud approximately three times the mass of Earth that is falling into the accretion zone of Sgr A*. Our observations fully constrain the cloud's orbit. It is highly eccentric with a pericenter distance of only 3100 times the Schwarzschild radius. The pericenter passage will happen in summer 2013 and already now we can see that the cloud has begun to tidally disrupt due to the black hole's gravitational force. The cloud also is a probe for the properties of the accretion flow, and ultimately we might have a chance to see how a massive black hole is being fed.

The CO/CO2 ratio varies dramatically among comets and is uncorrelated with JF vs NIC or with any dynamical measure of evolution. Correspondingly, the ratios of each to water vary dramatically. The high ratios of CO2 to CO require, if it is not an evolutionary process, that the CO2 form by grain surface chemistry (on a CO+H2O grain). But even more important, this probably also requires extensive mixing in a common zone of formation of both JFCs and LPCs/NICs. This zone lies in between the CO2 and CO snow lines, most likely in the giant planets region. The D/H ratio in comets as well as the diversity of colors of cometary nuclei support the same view. A scenario where all comets formed in a wide region with subsequent disruption and mixing as the giant planets migrated inward then outward is plausible. It has direct implications on the structure and heterogeneity of cometary nucleus resulting from the accretion of cometesimals of different natures.

This is a fairly short paper, but it is the first from the multi-cycle HST program to find the most distant supernovae. I will expand on that a little bit as well.

The gas content, stellar configuration, and overall appearance of low-mass galaxies can be significantly changed by external influence, particularly in dense environments like galaxy clusters. Tidal forces can remove dark matter and heat stellar disks; the pressure of the intracluster medium can strip the gaseous halo and even remove gas from the disk. Within this framework, I would like to discuss questions like these: How (in)efficient is ram pressure stripping in halting star formation in the disk, and under which conditions? How much harm can tidal forces from the group/cluster potential do to the baryons, and where is "harassment" actually relevant? Did the destruction of nucleated low-mass galaxies lead to ultra-compact dwarfs? If we want to investigate the role of such mechanisms for transforming late-type into early-type galaxies, on which epochs should we focus our studies, and how wrong are we doing when we simply compare today's populations with each other?

The CoRoT and Kepler space missions, while still ongoing, already revolutionised our view on stellar pulsation. After a very brief introduction in asteroseismology, we illustrate how the immense advantage of having long-term uninterrupted data from space with a factor 100 better precision compared to data from the ground implies large progress in the tuning of stellar physics. In particular, we focus on some cases where gravity-mode oscillations were detected in addition to acoustic modes and show how this allowed modelling of the near-core regions in stars. We end by highlighting future prospects based on the continuing data gathering by both missions while pointing out some challenging issues in the theory of stellar structure that need to be resolved to properly interpret the space data.

There is a peculiar difference between the metallicty distribution of field stars and the metallicity distribution of clusters in galactic haloes. The ratio between metal-rich clusters and metal-rich field stars is much lower than the ratio between metal-poor clusters and metal-poor field stars. These ratios also show a dependence on location in the halo. This might be due to a combination of several possible effects which may depend on metallicity and environment: - (a) clusterformation vs starformation efficiencies depends on metallicity and environment - (b) the infant-mortality rate of metal-rich clusters is higher than for metal-poor clusters - (c) the dynamical evolution of clusters depends strongly on metallicity and environment. I will discuss some of the observation and hope to have discussions/suggestions/comments on these and other effects that may play a role.

Galaxies grow with time through both discrete galaxy mergers and smooth gas accretion. When and how this growth occurs, and the role of mergers in defining the properties of today's galaxies, remain outstanding observational questions. Observational estimates of the galaxy merger rate and its evolution can vary by factors of 10, depending upon the method and assumptions used to count mergers. Using physical-motivated timescales from a large suite of galaxy merger simulations, I am able to reconcile the discrepancies between different measurements of the galaxy merger rate at z<1. The frequency of gas-rich mergers has increased strongly from z~0 to z~1, while the global galaxy merger rate evolved more modestly. Finally, I will discuss the prospects for identifying galaxy mergers at z~2 and beyond with the Cosmic Assembly Near-infrared Extragalactic Legacy Survey.

In order to achieve the optimal scientific return from the VLT, ESO has developed an end-to-end data flow system from proposal entry to science archive that provides the backbone infrastructure for VLT operations. User support is one of the main nodes of this schema, acting as the main interface between ESO and its users’ community. It thus provides support to the Observatory in operating the VLT and to all users of ESO (V-)facilities in the definition and implementation of the best observing strategies in order to achieve their scientific goals. But this is just the core task … fortunately (and sometimes unfortunately) we do much more than that!

'Radio mode' feedback from an active nucleus is now thought to play an important role in regulating the star-formation history of massive galaxies. Confusingly, radio jets have been invoked both to trigger star formation in galaxies and to suppress star formation. I'll show some results from our recent observational work which uses large-area radio and optical surveys to study the relationship between the radio properties of massive galaxies and their stellar populations. I'll also say something about the new Australian Centre of Excellence for All-sky Astrophysics (CAASTRO), and discuss the ASKAP FLASH survey, a blind all-sky survey in which we plan to probe neutral hydrogen in galaxies out to redshift z=1 by detecting the 21cm HI line in absorption against background radio sources.