"The Most Massive Stars in the Local Universe"
Paul Crowther (University of Sheffield)

Abstract The lower limit to the mass of stars is well defined, while the upper limit remains controversial. I shall summarise evidence in support of the currently accepted limit, and present recent VLT-based studies of the brightest members of young, nearby star clusters which argue for a higher limit. Consideration is given to questions of binarity using a variety of methods, while we present simulations of star clusters which argue for an upper mass limit close to 300 solar masses. The wider significance of this limit is discussed both for the integrated properties of unresolved star clusters and the possibility that pair-instability supernovae exist in the local universe, as proposed for SN 2007bi.

"Critical Tests of Theory of the Early Universe using the Cosmic Microwave Background"
Eiichiro Komatsu (MPA)

Abstract The Cosmic Microwave Background (CMB), the fossil light of the Big Bang, is the oldest light that one can ever hope to observe in our Universe. The CMB provides us with a direct image of the Universe when it was still an "infant" - 380,000 years old - and has enabled us to obtain a wealth of cosmological information, such as the composition, age, geometry, and history of the Universe. Yet, can we go further and learn about the primordial universe, when it was much younger than 380,000 years old, perhaps as young as a tiny fraction of a second? If so, this gives us a hope to test competing theories about the origin of the Universe at ultra high energies. In this talk I review the present status and future prospects on our quest to probe the physical condition of the very early Universe.

"Reionisation via the Lyman-alpha line"
Jamie Bolton (University of Nottingham)

Abstract The first luminous objects to form in the Universe produced ultra-violet photons which photo-ionised and heated the previously cold and neutral intergalactic medium (IGM). Observing the impact of the reionisation era on the IGM therefore provides us with an indirect probe of the formation and evolution of the first galaxies. Low frequency radio observations of the high redshift Universe will provide an exciting new window into this important epoch in the near future, but in the present the Lyman-alpha line (both in absorption and emission) can also inform us about the physical state of the high redshift IGM. In this talk I will briefly review existing observational constraints on the reionisation era, before going on to discuss new developments arising from observations of Lyman-alpha absorption around bright quasars at z=6-7 and the abundance of Lyman-alpha emitting galaxies approaching z=7. These measurements may be used to test existing theoretical models for reionisation, and can yield fresh insight into the timing of reionisation as well the nature of the first sources of light in the early Universe.

"New clues to the type-Ia supernova progenitor puzzle"
Dan Maoz (Tel Aviv University)

Abstract Type-Ia supernovae (SNe Ia) are thermonuclear bombs in which about a solar mass of carbon and oxygen is burned into iron-peak elements. The "explosives" are apparently a white dwarf. SNe Ia are excellent cosmological distance indicators, and as such provided the first evidence that the cosmic expansion is accelerating. However, despite their confident use in cosmology, a major embarrassment remains: no one knows, based on direct evidence, what exactly is exploding. Two scenarios have been long considered for explaining how a white dwarf can ignite and explode as a SN Ia. In the "single-degenerate" picture, a white dwarf accretes matter from a companion "normal" star (i.e. a star with a classical equation of state), until approaching the Chandrasekhar limit and igniting. In the "double-degenerate" picture, a close white-dwarf binary loses energy and angular momentum to gravitational waves, until the two white dwarfs merge, thus starting the ignition and the thermonuclear runaway. However, both scenarios have theoretical and observational problems, and little or no direct evidence to support them. SN Ia rates, as a function of cosmic time and environment, can provide clues. I will show how many recent measurements are converging toward a single SN Ia "delay-time distribution" - the SN Ia rate, as a function of time, that would follow a hypothetical short burst of star formation. The emerging function is remarkably similar to what one expects from white dwarf mergers, based directly on the fundamentals of gravitational wave emission. A measurement of the Galactic binary white dwarf merger rate also suggests there may indeed be enough such mergers to serve as the SN Ia progenitors.

"Chemical and physical processes in the earliest phases of star formation"
Paola Caselli (University of Leeds, UK)

Abstract The initial conditions in the process of star and planet formation are to be found in pre-stellar cores, which are dense (n_H > 10^5 cm-3), cold (T < 10 K), centrally concentrated and gravitationally contracting regions embedded in molecular clouds. Knowledge of the physical structure and kinematics of pre-stellar cores is needed to put constraints on theories of star and planet formation. This requires a good understanding of the pre-stellar core chemical structure, as spectral line profiles of trace species provide the only diagnostics of the dynamics leading to star and planet formation. Because of their simple structure and quiescent nature, pre-stellar cores are also ideal laboratories in which to measure key astrophysical processes and parameters. I will review work on pre-stellar cores in low-mass star-forming regions, showing Herschel observations and how ALMA will unveil the still unexplored central few hundreds AU of pre-stellar cores, the future stellar system cradles. I'll then move to high-mass star-forming regions and show that our work on nearby pre-stellar cores has provided a way to unveil massive starless cores and test star formation theories. Cycle 0 ALMA and OT2 Herschel data will be presented.

"The Solaris Project: A Timing Survey For Circumbinary Planets Around Eclipsing Binary Stars"
Maciej Konacki (Torun, Poland)

Abstract The SOLARIS project aims to detect from the ground circumbinary planets with the timing of eclipses of eclipsing binary stars. A network of four robotic 0.5-m telescopes on three continents (Australia, Africa and South America) will be established to carry out high cadence, high precision photometry of a sample of eclipsing binary stars. Three of the telescopes are already installed and the fourth one will become operational in the second half of 2013. The project's web site is www.projectsolaris.eu/.

This effort is accompanied by our radial velocity (RV) survey for circumbinary planets which employs our novel iodine cell based technique tailored to provide very high precision RVs of double-lined binaries. Altogether these two efforts, targeting about 300 eclipsing binary stars, constitute the biggest ground based survey for circumbinary planets. Moreover, we expect that both these efforts will have a significant impact on the observational stellar astronomy. In particular for at least half of our sample we expect to deliver masses of the stars with an accuracy 10-1000 times better than the current state of the art.

"Recent insights into Planet Formation"
Hilke Schlichting (UCLA/Caltech)

Abstract I will discuss recent insights that we have gained into planet formation from our solar system. In the first half of my talk, I will focus on the Kuiper belt, located at the outskirts of our planetary system, which provides a snapshot of earlier stages of planet formation and is therefore an ideal laboratory for testing planet formation theories. I will show how we can use the Kuiper belt size distribution to gain new insights into runaway growth and initial planetesimal sizes during planet formation and show how studying small km-sized Kuiper belt objects enables us to put our Kuiper belt into context of debris disks around other stars. In the second half of my talk, I will review dynamical models and geochemical constraints from the Earth, Moon and Mars and discuss their implications for the last stage of terrestrial planet formation.

"Extreme Astrophysics with Revolutionary Radio Telescopes"
Rob Fender (University of Southampton)

Abstract Against the background of the (mostly) Unchanging Heavens, the universe is punctuated by dramatic explosions and accretion events in which extremes of density, pressure, temperature, magnetic field and space-time curvature are reached which will be forever unattainable in any Earth-bound laboratory. Studying these events allows us to probe both the underlying physics as well as the effect of these massive injections of energy on the surrounding interstellar and intergalactic media. Such events are ubiquitously associated with radio emission, resulting from the interaction of highly accelerated electrons with magnetic fields. In this talk I will outline how and where in the universe we use radio emission to understand the budget of explosive feedback, and how a new generation of radio telescopes en route to the Square Kilometre Array have the potential to revolutionize our understanding of extreme astrophysics.

"Using massive clusters to probe structure formation and the first galaxies in the Universe: the CLASH project"
Piero Rosati (ESO)

Abstract Massive galaxy clusters represent important signposts in the history of structure formation and evolution, and are also natural gravitational telescopes which are able to bring lensed primordial galaxies from the earliest epochs into comfortable reach for detailed studies. The CLASH project (Cluster Lensing And Supernova survey with Hubble) combines an HST Treasury program to obtain panchromatic 16-filter (ACS+WFC3) imaging of 25 carefully selected massive clusters, with panoramic ground-based imaging, a large spectroscopic campaign with VLT/VIMOS and other multi-wavelength observations. This program was designed to provide landmark progress in the investigation of the mass distribution of galaxy clusters, at <z>~0.4, specifically the measurement of dark matter and total density profile shapes, over a wide radial range and over cosmic time, thus testing distinctive predictions of the LCDM cosmological model and structure formation scenario. The homogeneity and high quality of this combined data set allows us to probe matter density profiles with unprecedented accuracy over 3 decade in radius from a combination of independent probes (lensing, X-ray, and dynamics), with a significant mitigation of systematic effects.

"How the Milky Way Built its Disk"
Hans-Walter Rix (MPIA Heidelberg)

Abstract If we could map the global structure of the Milky Way's stellar disk, looking only at stars of a given age or abundance, it would be a direct route to delineating empirically how a typical large galaxy disk was built up. We have solved the problem of how to look at our own Galaxy this way, using large ground-based spectroscopic surveys. I will show how the overall radial and vertical structure of the Milky Way's disk changes as a function of stellar abundances, which may serve as proxies for stellar ages. Through comparison with disk formation simulations, I will also discuss what this may mean for the build-up of the Milky Way disk and its evolution. Slicing the Milky Way's disk into sets of such stellar mono-abundance populations is also proving a powerful way of constraining the Galactic potential.

"The Galactic Bulge"
Ken Freeman (Mount Stromlo Observatory)

Abstract The boxy Galactic Bulge is believed to have formed long ago through a bar-forming and bar-buckling instability of the Galactic disk. In order to study the chemical and dynamical properties of this bulge, we have acquired spectra of 28,000 red giant candidate stars towards the bulge, and I will describe the outcome of this large survey (the ARGOS survey). We are able to estimate the distances for all of these stars, and remove several thousand stars which lie in the foreground or background of the bulge. The chemical properties of the bulge stars show that the bulge-forming instability moved stars from the early thin and thick disk into the bulge. These stars are now locked into the bulge as chemically identifiable fossils of the early disks. We are not able to put useful limits on the presence of an additional classical (merger-related) bulge component in the inner Galaxy, but our kinematical data are fully consistent with the predictions of the instability formation scenario.

"Cosmic Flows Project, Voyage to the Great Attractor"
Helene Courtois (University of Lyon)

Abstract "Cosmic Flows" project is focused on producing observed galaxy distances for 30,000 galaxies with systematic errors below 2%, almost ten times the number currently known and a five-fold improvement in systematics. The resultant velocity field is providing initial conditions for constrained numerical cosmological simulations "CLUES". The observed and the simulated universe are then comparatively studied. This synergy of observations and theory distinguishes this program, and should lead to fundamental discoveries. Specifically, the program should give a definitive answer to an outstanding problem in cosmology since 1996 : the cause of the motion of 630 km/s of the CMB. On the path to this goal we are learning new informations on the dynamics of Large Scale Structures: the large coherent flows of galaxies away from voids and towards the Great Attractor region. We derive a most recent value for the Hubble constant at Ho=75 km/Mpc/s using SNIa. "Cosmic Flows" is bringing together unique expertise in radioastronomy, optical and space near-infrared surface photometry, theoretical astrophysics and numerical simulations. We tackle a frontier question: by learning our "cosmography", we look for where exactly are the Dark Energy and Dark Matter that dominate the cosmology?

"Terzan 5: the remnant of a pristine fragment of the Galactic Bulge?"
Francesco Ferraro (University of Bologna)

Abstract Terzan 5 is a stellar system commonly catalogued as a Globular Cluster (GC), located in the inner Bulge of our Galaxy. Two distinct sub-populations have been recently discovered in this system (Ferraro et al. 2009, Nature, 462, 483). They define two well separated red clumps in the (K, J-K) color-magnitude diagram (CMD) and show very different iron content: ΔFe ~0.5 (such a large difference in iron abundance has been found only in another GC-like stellar system, omega Centauri, in the Halo of the Galaxy). Moreover, the abundance of light elements measured in both sub-populations has been found not to follow the typical anti-correlations observed in genuine GCs and the overall chemical patterns of the two populations appear strikingly similar to those of the Bulge stars (Origlia et al. 2011). These observational results demonstrate that Terzan 5 is not a genuine GC, but a stellar system that experienced complex star formation and chemical enrichment histories. The strong chemical link with the Bulge, together with the location in the inner region of it, suggest that Terzan 5 (at odds with omega Centauri) is not the nucleus of an accreted dwarf galaxy, but possibly the relic of one of the pristine fragments that contributed to form the Bulge itself.

"Molecular gas and star formation in early-type galaxies"
Martin Bureau (University of Oxford, UK)

Abstract Despite pervasive residual star formation, early-type galaxies are generally considered "red and dead", composed exclusively of old stars with little gas and no star formation. Here, the molecular gas content of early-type galaxies is constrained and discussed in relation to their evolution, providing a much greater understanding of the gas cycle in these objects and arguing for the continuing importance of (minor) mergers and cold gas accretion. Early-types also provide a new laboratory to study star formation, revealing unusual star-formation scaling relations.

First, nearly a quarter of local early-types are shown to possess a substantial amount of molecular gas, the necessary ingredient for star formation, independent of mass and environment. Second, a variety of molecular gas morphologies is revealed. The kinematics of the molecular gas and stars are often misaligned, implying an external gas origin in at least half of the systems in the field, while external gas accretion is shut down in clusters. Despite this, the kinematics of the molecular is often regular, allowing kinematic work ranging from Tully-Fisher studies to black hole mass measurements. Third, many objects appear to be in the process of forming regular kpc-size decoupled disks, and a star formation sequence can be sketched by piecing together multi-wavelength information. Early-type galaxies do not seem to systematically obey all our usual prejudices regarding star formation (e.g. Kennicutt-Schmidt law and far infrared-radio continuum correlation), suggesting a greater diversity of star formation processes than observed in disk galaxies. Last, a first step toward constraining the physical properties of the molecular gas in early-type galaxies is taken, by modeling the line ratios of temperature-, density- and opacity-sensitive molecules in a few objects.

"Direct imaging of exoplanets"
Anne-Marie Lagrange (IPAG, Grenoble)

Abstract Most of the exoplanets known today have been discovered by indirect techniques, based on the study of the host star radial velocity or photometric temporal variations. The planet populations explored are in the first 5-8 AU from the central stars, and have provided precious information on the way planet form and evolve at such separations. Direct imaging on 8-10 meter-class telescopes allows detection of giant planets at larger separations (currently typically >5-10 AU), complementing thus indirect techniques. So far, each of the -yet very few- giant planets imaged provides an opportunity of unique dedicated studies of their orbital, physical and atmospheric properties and sometimes also on their interaction with "second generation", debris disks. Actually, these few detections already challenge formation theories.

I will present the results of direct imaging surveys obtained so far, what they already tell us about giant planet formation and evolution. Individual and emblematic cases will be detailed; they illustrate what future instruments will routinely deliver for a much larger number of stars. I will also point out the limitations of direct imaging as well as the needs for further work in terms of planet formation modelling. I will finally present the tremendous progress expected in this field thanks to forthcoming planet imagers on 8-10 meter class telescopes, and on Extremely Large optical Telescopes.

"Characterizing the Early Stages of Massive Star Formation: From Infrared-Dark Clouds to Hot Molecular Cores"

Izaskun Jimenez-Serra (ESO)

Abstract
Observations at mid-IR and far-IR wavelengths carried out with the Spitzer and Herschel satellites have revealed that the ISM in our Galaxy is highly organized in cold and dense filamentary structures. The most massive ones are called Infrared-Dark Clouds (or IRDCs) and present typical masses that range from 1000 Mo to 10000 Mo. IRDCs are believed to be the initial conditions of massive star and star cluster formation, which is known to end in chemically rich, hot molecular cores (Hot Cores). Although a large effort has been done in the past to determine the global physical properties of these clouds and of their dense (and cold) clumps/cores, it still remains unclear what mechanisms are responsible for the formation of IRDCs, and how they fragment forming cold IRDC cores. In addition, the evolutionary sequence by which cold IRDC cores evolve into Hot Cores is poorly known, and information about the internal physical structure of these cores is still lacking. In this talk, I will present our recent results on several comprehensive studies of the kinematics and chemistry of the molecular gas i) toward a filamentary IRDC, G035.39-00.33; ii) toward a sample of cold IRDC clumps recently detected with Herschel; and iii) toward a massive Hot Core, AFGL2591 VLA 3. From these results, we find that the combination of complete molecular line datasets with modeling of the chemistry in star forming regions, is key not only to obtain information about the large-scale processes involved in the formation of IRDCs, but also to fully characterize the evolutionary sequence from cold IRDC cores to massive Hot Cores, with their internal physical structure.

"Lessons learned from detections of CO in two atypical comets"

Lucas Paganini (NASA Goddard Space Flight Center)

Abstract
Recent results by the space-based NASA's DIXI and Japanese Akari missions demonstrated that the carbon chemistry in comets remains incompletely understood. DIXI found that the outgassing in comet 103P/Hartley 2 was driven primarily by carbon dioxide. The Akari survey of 18 comets revealed a significant abundance of CO2, but surprisingly it detected only upper limits for carbon monoxide in most comets comprising their sample. Our recent ground-based VLT/CRIRES observations showed a relative large amount of CO in Oort cloud comet C/2009 P1 (Garradd) at 2 AU, and also in the border-line Jupiter Family/Centaur comet 29P/Schwassmann Wachmann 1 at 6.3 AU. In this presentation, I will report these detections, compare them to existing studies, and explore possible links between chemical composition and cometary origins.

"Are we alone in the Universe?"

Jorge Melnick (ESO Santiago)

Abstract
In 1960 the radio astronomer Frank Drake started a search of radio signals from extraterrestrial technologically advanced civilizations using the Green Bank radio telescope. In order to quantitatively discuss the possibility of finding other civilizations in our Galaxy, Drake wrote down the main factors that he thought would need to be addressed to understand the odds of finding radio signals from extraterrestrial intelligent beings. The product of these factors became known as the Drake Equation.

Advances in many fields of science since 1960 enable us today to use Drake's equation to make scientifically sound estimates of the number of intelligent civilizations expected to exist in our Galaxy. In this presentation I will show that using the best available data, the probability of finding intelligent life on other planets depends critically on Drake's longevity parameter: how long does a technological civilization manage to survive natural and self-induced threats?

"Complex molecules in Orion"

Tzu-Cheng Peng (ESO)

Abstract
The Orion molecular cloud 1 (OMC-1) is a unique environment for the study of interstellar chemistry, especially in the surroundings of the Orion BN/KL region. As one of the closest star-forming regions, many complex molecules have been detected toward Orion BN/KL, including a few deuterated molecules. In this talk, I will present the recent results from our IRAM PdBI observations and focus on two molecules, deuterated methanol CH2DOH and acetone (CH3)2CO. I will also discuss the deuterium chemistry and nitrogen/oxygen-differentiation in Orion BN/KL and their future prospects in the ALMA era.

"Cosmic Rays at the Highest Energies"

Karl-Heinz Kampert (Bergische Universität Wuppertal)

Abstract
Recent data of giant air shower observatories, most importantly of the 3000 km^2 large Pierre Auger Observatory operated in Argentina, have led to a number of major breakthroughs in the field of ultra-high energy cosmic rays. Most importantly, a distinct flux suppression above 5∙10^19 eV has been has been established unambiguously. This, together with upper limits on photon and neutrino fluxes at ultra-high energy have ruled out particle physics motivated "top-down" source processes, such as the decay of super-heavy particles, to account for a significant part to the observed particle flux at the highest energies. Moreover, there are indications for an anisotropic distribution of the arrival directions of particles with energies greater than 5∙10^19 eV. These results are typically considered as strong support of source scenarios in which particle acceleration takes place at sites distributed similarly to the matter distribution in the universe, with energy loss processes in the CMB leading to the observed flux suppression (GZK-effect). However, the cosmic ray mass composition and the small level of anisotropies in arrival directions suggest that the end of the cosmic ray spectrum is not dominated by the GZK-effect but by an extragalactic source (or source population), possibly within the GZK-horizon, running at its maximum electromagnetic rigidity R=p/Z. In this talk, we shall review cosmic ray data at the highest energies, discuss their implications to understanding their origin, and we shall address some synergies to particle physics currently performed at the LHC.