The internal antarctic plateau revealed in the last years to be a site with interesting potentialities for the astronomical applications due to the extreme dryness and low temperatures, the typical high altitude of the plateau, the weak level of turbulence in the free atmosphere down to a just few tens of meters from the ground and the thin optical turbulence layer developed at the ground. The main goal of a site testing assessment above the internal antarctic plateau is to characterize the site (optical turbulence and classical meteorological parameters) and to quantify which is the gain we might obtain with respect to equivalent astronomical observations done above mid-latitude sites to support plans for future astronomical facilities. Our group has been involved, since a few years, in studies related to the assessment of this site for astronomical applications that include the characterization of the meteorological parameters and optical turbulence provided by general circulation models as well as mesoscale atmospherical models and the quantification of the performances of Adaptive Optics (AO) systems. In this talk I will draw the status of art of this site assessment putting our studies in the context of the wide international site testing activity that has been done in Antarctica. I will focus on the site assessment relevant to astronomical applications to be done in the visible up to the near infrared ranges, i.e. those ranges for which the optical turbulence represents a perturbing element for the quality of the images and the AO techniques an efficient tool to correct these wavefront perturbations.

Submillimeter dust continuum emission traces high molecular column densities and, thus,dense cloud regions in which new stars are forming. Surveys of the Galactic plane in suchemission have the potential of delivering an unbiased view of high-mass star formationthroughout the Milky Way. The location of the APEX telescope on the Chajnantor plateau inChile is ideally suited for mapping the inner Galaxy. ATLASGAL, The APEX Telescope LargeArea Survey of the Galaxy at 870 μm, is a survey of the Galactic planeusing the Large APEX Bolometer Camera (LABOCA), in the Galactic longitude and latituderanges of  ±60 and  ±1.5°, respectively. This survey is providing an unbiased sample ofcold dusty clumps in the Galaxy at submillimeter wavelength and a variety of molecularline follow-up observations have been started to characterize the physical and chemicalconditions in the newly found clumps. Here, first results from this survey and itsfollow-up programs are described.

The Gaia space satellite will perform absolute astrometry, aiming at the definition of aglobal astrometric reference frame at visual wavelengths. Within this reference system, itwill be very difficult to identify possible errors in the measurements or in the datareduction process that brings about the definition of the final catalogue. The Gaia DataProcessing and Analysis Consortium (DPAC) has established an Astrometric Verification Unit(AVU) to verify crucial steps in the baseline data processing chain and report on anysignificant difference. This process is essential in order to guarantee a high qualitycatalogue to the larger scientific community. We describe here the global spherereconstruction (GSR) component of AVU hosted by the Italian data processing centre atTorino (DPCT).

To fulfil its numerous science objectives, the Gaia mission needs to account for theimpact of the radiations at CCD level. Through the defects generated in the silicon, theradiations will not only degrade the overall signal-to-noise ratio of the measurements,but also corrupt them with a bias to be corrected on ground. In order to characterize thiseffect, and help deriving a proper calibration strategy, an extensive radiation testcampaign has been carried out in EADS Astrium since 2006, covering the differentinstruments and CCD variants. We present an overview of this radiation test bench, and thedifferent investigations performed so far and associated findings.

Irradiation is one of the main processes which influences the evolution of dust in astrophysical environments. This article reviews the basics of particle-matter interactions and gives an introduction to the induced modifications including phase transformation, sputtering, implantation, charging effects and transmutation. We also discuss the role of the nature of the incident particle (energetic photons, electrons and ions) as a function of its energy. Finally, we briefly review the main results obtained by irradiation studies on ices, carbonaceous matter and silicates.

We analyze a sample of Swift X-ray and optical GRB afterglows which werechosen so as to reduce selection effects against the weakest events. We tentativelyidentify important differences in GRBs that show a fast decay with respect to the averageGRB, in particular a tendency for the more energetic bursts to have a steeper afterglowdecline. An explanation to this finding could be bursts in a wind environment are onaverage more energetic than bursts occurring in a constant density medium.

Important progress has been made within the past few years regardingthe theory of low mass stars (m < 1 M⊙) and brown dwarfs(m < 0.075 M⊙).The main improvements concern the equation of state of dense plasmasand the modelling of cool and dense atmospheres,necessary for a correct description of such objects. Thesetheoretical efforts now yield a better understanding of these objectsand good agreement with observations regarding colour-magnitudediagrams of globular clusters, mass-magnitude relationshipsand near-IR colour-magnitude diagrams for openclusters. However uncertainties still remain regardingsynthetic optical colours and the complex problemof dust formation in the coolest atmosphere models.We will present a review of the current success and uncertaintiesof the theory of these objects, which may guide forthcoming projectswith GAIA.

We present an analysis of the properties of H i holes detected in 20 galaxies that are part of “The H i Nearby Galaxy Survey”. We detected more than 1000 holes in total in the sampled galaxies. The holes are found throughout the disks of the galaxies, out to the edge of the H i disk. We find that shear limits the age of holes in spirals. Shear is less important in dwarf galaxies which explains why H i holes in dwarfs are rounder, on average than in spirals. Shear is particularly strong in the inner part of spiral galaxies, limiting the lifespan of holes there and explaining why we find that holes outside R25 are larger and older. We proceed to derive the surface and volume porosity and find that this correlates with the type of the host galaxy: later Hubble types tend to be more porous. The size distribution of the holes in our sample follows a power law with a slope of aν ~ −2.9. Assuming that the holes are the result of massive star formation, we derive values for the supernova rate (SNR) and star formation rate (SFR) which scales with the SFR derived based on other tracers. If we extrapolate the observed number of holes to include those that fall below our resolution limit, down to holes created by a single supernova, we find that our results are compatible with the hypothesis that H i holes result from star formation.

This paper introduces the The Milky Way Unravelled by Gaia conference proceedings.

Interstellar gas is thought to be heated by photoelectronsejected by small grains and PAHs. This process is reviewed and evidence for its importance is examined.In particular, the importance of the PAH charge for the photo electric effect and for the spectral characteristics of interstellar PAHs is discussed.

The ESA space mission Gaia, planned to be launched at the end of 2013, will make astrometric, photometric and spectroscopic measurements of about 1 billion sources in our Galaxy. Amongst these sources will be numerous multiple systems. In the processing chain eclipsing binaries (EBs) will be detected and, if possible, their period and characteristics determined. Here we summarize the various steps that are foreseen to automatically classify and characterise these EBs.

The Gaia-ESO Survey (GES) is a large public spectroscopic survey that aims at observing with FLAMES@VLT the main stellar components of our Galaxy. The study of the population of open clusters is one of the main objectives of GES. We present some results from the first 18 months of observations, among them, a preliminary view of the radial metallicity gradient as traced by open cluster data and a comparison of the chemical patterns of clusters located in different parts of the Galactic disk.

VIHI: the Visible and Infrared Hyperspectral Imager is one of the three channels of the Simbio-Sys instrument for the BepiColombo mission to Mercury. Its scientific objective is to study the hermean surfaces composition by sensing the photon flux reflected off the planet. VIHI works in the range of 400 to 2000 nm with a spectral resolution around a few hundreds. The particularity of this channel is the use of a single detector matrix (264 × 264) for both visible and infrared wavelengths. Getting the visible part of the detector responsivity is achieved by thinning an infrared HgCdTe matrix because visible light is completely absorbed inside the substrate. The thinning process is well controlled since a long time and was used to increase number of thermal cycle of the hybrid devices. Recently, this process is able to remove completely the substrate and, thus, open the detector to the visible range. The detector is a custom design made by Raytheon Vision System in Goleta (USA). In this paper, we will describe the expected performances of the detector which is designed to work in the very harsh radiation environment of Mercury.

Our survey of long-baseline infrared and optical interferometry measurements is producing considerable numbers of directly determined stellar angular sizes. We use our sample of 124 high-precision (5%) angular stellar diameter values and correlate them with stellar magnitude values from the literature to produce empirical relations for main-sequence stars between observed apparent magnitudes, stellar colors, and angular sizes (surface brightness relations). We find a significant dependence on stellar metallicity for (B − V) colors. The scatter in the calculated relations is small (∼5%), which makes them a robust tool for the prediction of main-sequence stellar angular sizes based on photometry. We apply these relations via the calculation of the radius of the multiplanet host star GJ 667 C.

We present the Gaia-Groundbased Observation Service for Asteroids (Gaia-GOSA) which release is planned for April 2015. This web service aims to lay the foundation of a worldwide collaborative network of observers with the goal of collecting lightcurves around isolated photometric observations by the European Space Agency (ESA) Gaia mission. Such data will allow us to extract physical parameters of the observed asteroids, such as rotational period. Moreover, we will obtain a minimum threshold of the asteroid's lightcurve amplitude. The resulting catalogue might be used to enhance some of the problematic inversion scenarios or also for validation purposes.

In recent years, astronomical photometry has been revolutionised by space missions such as MOST, CoRoT and Kepler. However, despite this progress, high-quality spectroscopy is still required as well. Unfortunately, high-resolution spectra can only be obtained using ground-based telescopes, and since many interesting targets are rather faint, the spectra often have a relatively low S/N. Consequently, we have developed an algorithm based on the least-squares deconvolution profile, which allows to reconstruct an observed spectrum, but with a higher S/N. We have successfully tested the method using both synthetic and observed data, and in combination with several common spectroscopic applications, such as e.g. the determination of atmospheric parameter values, and frequency analysis and mode identification of stellar pulsations.

Within the Cold Dark Matter scenario the hierarchical merging paradigm is the natural result to form massive galactic halos by the minor mergers of sub-halos and, by this, inherently their stellar halo. Although this must be also invoked for the Milky Way, the context of chemical and kinematic coherence of halo stars and dwarf spheroidal galaxies is yet unsolved a focus of present-day research. To examine this issue we model the chemo-dynamical evolution of the system of satellites selected from the cosmological Via Lactea II simulations to be similar for the Milky Way environment but at an early epoch.

The emission properties of the components of the multiphase interstellar medium (ISM) require observations at very different wavelengths covering the range from X-rays for the hot phase to radio emission for the non-thermal component. This contribution gives an overview of the observational evidence for the presence of a multiphase ISM in halos of spiral galaxies. It is shown that the presence of halo gas correlates with the starformation rate in the disk. Recent radiocontinuum observations for NGC 253 are discussed with regard to the propagation of cosmic rays into the halos.

A review of some of the most important studies of the past several decades pertaining to the study of atomic diffusion in stellar atmospheres is presented. A brief description of various studies of radiative accelerations and diffusion calculations in stellar atmospheres is given. Several physical phenomena such as ambipolar diffusion, light-induced drift and the effect of magnetic fields on diffusion are discussed. Results from recent self-consistent model atmospheres including elemental stratification are also reviewed. Particularities of radiative acceleration calculations in stellar atmospheres as well as difficulties and future challenges related to diffusion calculations in stellar atmospheres are also presented.

Two competing theories posit that Ultra Compact Dwarfs (UCDs) form either as the stripped nuclei of dwarf galaxies or as giant globular clusters (GGCs) associated with the largest globular cluster (GC) systems. By focussing on the field and group environments where young UCDs may be most common, we have discovered the first UCD that is clearly the result of recent (< 4Gyr ago) stripping of a companion galaxy during a minor galaxy merger. However, we have also found a definitive case of a multiple-UCD system created via GC formation processes, which are likely associated with major galaxy mergers.