Identification of first and second turnaround radii in groups of galaxiesprovide interesting scaling relations and may constrain cosmologicalparameters.

ELSA (European Leadership in Space Astrometry) is a four-year, EU-funded ResearchTraining Network ending in September 2010. It has employed 10 postgraduate students and 5postdocs for 2–3 years and financed a number of workshops, training events and topicalmeetings, culminating in the present symposium. The primary goal of ELSA is to train youngscientists in the context of the Gaia project while contributing to the scientificpreparations for the mission. The organization, aims and history of ELSA are outlined.

Since January 1st, 2010, the IAU (International Astronomical Union) fundamental celestialreference frame has been the 2nd International Celestial Reference Frame (ICRF2), which iscomposed of Very Long Baseline Interferometry (VLBI) positions for more than 3000extragalactic radio sources. This frame is constantly improving through joint efforts ofthe VLBI community. By surveying the whole sky up to magnitude 20, the European spaceastrometric mission Gaia will soon create its own celestial reference frame directly inthe optical domain and with many more sources. By 2015–2020, the two frames will thuscohabit and it will be important to align these to the highest accuracy for consistencybetween optical and radio positions. In this paper, we present the various observationalapproaches that are undertaken to improve the VLBI frame in the future. These includeextension to weaker sources for densification, extension to higher radio frequencies totake advantage of the more compact morphology of the sources at these frequencies, andfurther observations in the southern hemisphere for homogeneous sky coverage. We alsoelaborate on how such future radio frames should contribute to highly-precise alignmentbetween the VLBI and Gaia frames within the next decade.

The installation and operation of an ELT and the associated astronomical instruments requires considering the reliability aspects (the ability to work satisfactorily for a specified time under given environmental conditions) and the maintenance/maintainability aspects from the beginning of an ELT/instrument project.In particular, for equipment working in the extreme antarctic environment the reliability and maintainability characteristics are the main factors influencing, i)the availability of the equipment for the scientific research activities, and ii) the annual and the long term operation costs (Life Cycle Costs, LCC).These characteristics have to be designed and built into the equipment.The presentation describes the general strategy to be followed, the main activities to be done, and the decisions to be taken during the individual project phases from the identification of the user needs to the installation, commissioning and operation in order to guarantee high equipment availability and optimized maintenance effort and costs.

We present optical broad-band (UBVRI) aperture polarimetry of 52 post-AGB stars, selected from De Ruyter et al. (2006) and the Torun Catalog, based on the shape of their SED and near-infrared excess. We find 10 (19%) of the stars in our sample to have high polarization (P > 5%), 30 (56%) intermediate/low polarization (1% < P < 5%) and 13 (25%) very low (or non–polarized) polarization (P < 1%). Our observations show clear evidence of asymmetric circumstellar envelopes or equatorial density enhancement around post-AGB stars, probably formed at the beginning of the AGB phase. Some stars exhibit wavelength-independent polarization suggesting scattered light by large dust grains or free electrons (Thomson scattering), while others show wavelength-dependent polarization originated from scattering by small dust grains (Rayleigh scattering). Finally, we conclude that highly polarized sources (P > 3%), show systematically [12] − [25] > 1.5, J − H > 0.5 and J − K > 0.5, clearly separated from the group of RV Tauri stars, which are found to have very low polarization (P < 3%).

We have studied the effects of the laboratory-measured, temperature-dependent dust emissivity indices on the FIR/sub-mmemission properties of amorphous silicate and amorphous carbonaceousdust. When the experimentally-determined temperature dependence of thedust emissivity index is taken into account we find temperatures thatcan differ by as much as 1.5 K and emissivity indices that can differby ~15%, with respect to the values obtained using publishedrefractive index data as is to calculate these quantities. Inaddition, we find that the observed diffuse ISM dust temperature of~17.5 K and emissivity index of 2 can seemingly be produced witha mixture of amorphous carbon and silicate grains only iftemperature-dependent dust emissivity indices are adopted. We findthat dust masses determined using the temperature-dependent dustemissivity indices are not significantly different from those derivedusing standard dust properties.


Caustics are formally singular structures that frequently form in collisionless media. The non-negligible velocity dispersion of dark matterparticles renders their density finite. We evaluated the maximum density ofthe caustics within the framework of secondary infall model of formation ofdark matter haloes. The result isthen used to demonstrate that caustics can be probedby properly stacking the weak-lensing signal of about 600 haloes. CFHTLS accompanied by X-ray observations and the space-based experiments like SNAP or DUNE can provide us with the required statistics.The extension of our results to more realistic models including the effects of mergers is outlined.


Weak gravitational lensing has become an important tool to study the properties of dark matter halos around galaxies, thanksto the advent of large panoramic cameras on 4 m class telescopes. Thisarea of research has been developing rapidly in the past few years,and in these proceedings we present some results based on theRed-Sequence Cluster Survey, thus highlighting what can be achieved withcurrent data sets. We present results on the measurement of virial masses as afunction of luminosity and the extent of dark matter halos. Muchlarger surveys are underway or planned, which will result in animpressive improvement in the accuracy of the measurements. However,the interpretation of future results will rely more and more oncomparison with numerical simulations, thus providing direct tests ofgalaxy formation models.

Antarctica offers unique conditions for ground-based observations, such as low sky background in the infrared, improved seeing, and low turbulence and scintillation noise. These properties are particularly beneficial to imaging, precision photometry, and infrared observations. It may be less clear if Antarctica offers equally compelling advantages for spectroscopy, in particular in the optical domain. However, scientific programmes that make use of imaging (or 3D) spectroscopy for selected follow-up studies of IR surveys, long-termmonitoring of extended targets and resolved stellar population studies in crowded fields, also benefit from the site conditions at Dome C.

Present studies on the evolution of the Milky Way are driven and shaped by how we conceive its stellar populations, in an on going process started by W. Baade seventy years ago. Despite much progress and advances in our understanding of these populations, inspection of their main properties is however hardly indicative of the path the Milky Way has followed to build up its mass. This is not only a matter of (stellar) age measurement, but more so the consequence of how we interprete the structures that we see in our Galaxy, often through the filter of our definitions of stellar populations. The panorama presented in the following pages opens the possibility that the present “filter” is not fully adequate. I start these Lectures with a summary of the main properties of the disks, bulge, and halo, and then present some of the new directions in the interpretation of the structure and evolution of the disk(s), with emphasis on chemical evolution. I discuss recent results in our understanding of the bulge, its stellar components and chemical evolution. Finally, I present the ideas currently proposed to explain the formation of the Galactic stellar halo. I conclude by examining how deeply all these new results question our present definition of stellar populations.

This paper deals with adaptive optics in the framework of very high-contrast astronomical imaging. Starting from a brief global overview of classical adaptive optics (AO) systems, the specificities and main characteristics of extreme AO (XAO) systems are exposed. Along the way from AO to XAO, some relevant points (relevant with respect to the goals claimed by high-contrast imaging techniques) are emphasized.

Ground- and space-based observations have confirmed the presence of oscillatory motions in prominences and they have been interpreted in terms of magnetohydrodynamic (MHD) waves. This interpretation opens the door to perform prominence seismology, whose main aim is to determine physical parameters in magnetic and plasma structures (prominences) that are difficult to measure by direct means. Here, two prominence seismology applications are presented.

We demonstrate the important role of anisotropic neutrino radiation on the mechanism of core-collapse supernova explosions. Through a newparameter study with a fixed radiation field of neutrinos, we show thatprolate explosions caused by globally anisotropic neutrino radiationrepresent the most effective mechanism of increasing the explosionenergy when the total neutrino luminosity is given. This is suggestive ofthe fact that the expanding materials of SN 1987A have a prolategeometry.

Global hyperbolicity is a classical and well-known concept, whichlies in the core of General Relativity. Here we discuss brieflyfive approaches to this concept. They yield different definitionswhich become natural in diverse contexts: the initial valueproblem, singularity theorems, existence of maximizing causalgeodesics, possibility to split globally the spacetime, causalboundaries. The neat formulation and definitive equivalencebetween these definitions have been completed only recently. Avery brief summary is presented.

By means of N-body simulations, we have investigated the impact of minor mergers on theangular momentum content and kinematical properties of a disc galaxy. Our simulationscover a range of initial orbital characteristics and the system consists of a massivegalaxy with a bulge and a stellar disc merging with a much less massive gasless companion.Our results show that: (1) during the process of merging, the disc of the primary galaxybecomes kinematically hotter and thicker; (2) its specific angular momentum alwaysdecreases, independent of the orbit or morphology of the satellite galaxy; (3) thedecrease in the rotation velocity of the primary galaxy is accompanied by a change in theanisotropy of the stellar orbits, which becomes increasingly radially dominated as themerger advances; (4) the radial velocity dispersion increases at all radii, but inparticular in the outermost regions; (5) at the same time, the transverse velocitydecreases throughout the whole disc, except in the inner region, where the constributionof bulge stars leads to an increase ofσt.

Our aim is to study the evolution of tidal dwarf galaxies. The firststep is to understand whether a model galaxy without Dark Matter cansustain the feedback of the ongoing star formation. We present testsof the evolution of models in which star formation efficiency,temperature threshold, initial distribution of gas and infall arevaried. We conclude that it is feasible to keep a fraction of gasbound for several hundreds of Myr and that the development of galacticwinds does not necessarily stop continuous star formation.

We present a model for the dispersal of protoplanetary disks by winds from either the central star or the inner disk. These winds obliquely strike the flaring disk surface and strip away disk material by entraining it in an outward radial-moving flow at the disk-wind interface. This interface lies several disk scale heights above the mid plane. The disk dispersal time depends on the velocity at which disk material flows into the mixing layer. If this velocity is ~10% of the sound speed, the disk dispersal time at ~1–10 AU is ~5 Myr for a 0.01 M๏ disk around a solar mass star, with a spherical wind launched from the inner disk or central star with a typical mass loss rate of 10-8M๏yr-1 and terminal velocity of vw = 100 kms-1. We conclude that wind stripping is not a dominant disk dispersal mechanism compared with viscous accretion and photoevaporation. Nevertheless, wind stripping may affect the evolution of the intermediate disk regions.

To determine the star formation histories of dwarf galaxies we use fossil methods. Compared to the color-magnitude diagrams analyzes, which are well tested and widely accepted, the studies of integrated spectra are still young. In order to assess their capabilities and limitations, we compare the results of three publicly available star formation recovery programs (StarLight, STECKMAP and ULySS).

A brief description of the various types of variable stars occuring in the advanced stages of stellar evolution is given.This includes the Planetary Nebulae Nuclei variables (PNNV), the PG 1159 variables, the sdB pulsators and the DB and DA white dwarf pulsators. In this review, the emphasis is put on the importance of diffusion for eitherthe excitation mechanism or the properties of the oscillations.

Thanks to development of some new detectors small compare to wavelength of detected wave, as we foreseen in SWIFTS that these detectors can be placed in the vanishing field along propagation of light in order to detect the Lippmann interferogram, we propose here to present basic of SWIFTS and review some concepts where detectors has already set inside optical components and thinking about extensions of the concept of SWIFTS in new optical instrumentation by including directly detectors inside optical component.