We review recent developments in the field of chemodynamical simulations ofelliptical galaxies, highlighting (in an admittedly biased fashion) the work conducted with our cosmological N-body/SPH code GCD+. We have demonstrated previously therecovery of several primary integratedearly-type system scalingrelations (e.g. colour-magnitude relation, LX − TX − [Fe/H]X) when employing a phenomenological AGN heating scheme in conjunctionwith a self-consistent treatment of star formation, supernovae feedback, radiative cooling, chemical enrichment, and stellar/X-raypopulation synthesis. Here we emphasise characteristics derivedfrom the full spatial information contained within the simulated dataset, including stellar and coronal morphologies, metallicity distributionfunctions, and abundance gradients.

Site testing data provides an essential part of the justification for funding any new astronomical facility by defining the technological design and determining the telescope performance, thus allowing the scientific objectives to be prioritised. Here we review the current status of site testing at Dome C by examining the range of instruments that have been, or are planned to be, deployed to the site. We then investigate in more detail preliminary data which has so far proven crucial for telescope design, data for which discrepancies exist between two or more instruments, and required data for which there are no current plans to obtain. We discuss the implications of this data on the technical design, expected performance, and the scientific capabilities for a 2.5 m class optical/infrared telescope. Finally, we identify the site parameters that require further study, and define the experiments necessary to determine these parameters.

Detection of a composite flux in Gaia photometry can serve as an indication of aphotometrically unresolved binarity and can allow us to contribute to the parameterizationof the components of binary systems. A main goal of the present study is to develop amethod of automatic photometric detection, based on theoretical stellar spectral energydistributions and general understanding of binary evolution.

The following procedure is applied to achieve the declared goal. One can compose possiblepairs of components, based on evolution concept, and using theoretical binary evolutionarytracks. This can be done for all stages of binary evolution, excluding perhaps the mostmarginal and rapid stages. Theoretical spectrophotometric spectral energy distributionsand response functions of Gaia photometric bands allows us to compute colour-indices ofsuch pairs, when they are unresolved, as well as of single stars. Usage of an interstellarextinction law gives us theoretical colour-indices of reddened objects, both single starsand unresolved binaries. When plotted on a multidimensional Gaia colour space, they allowus to indicate areas, where unresolved binaries can be easily separated from single stars.The procedure also indicates Gaia colour indices, suitable to distinguish those pairs fromsingle stars.

As an output of the procedure, a Gaia list of detected photometrically unresolvedbinaries with physical parameters can be compiled.

The standard model of cosmology suggests the existence of two components, “dark matter” and “dark energy”, which determine the fate of the Universe. Their nature is still under investigation, and no direct proof of their existences has emerged yet. There exist alternative models which reinterpret the cosmological observations, for example by replacing the dark energy/dark matter hypothesis by the existence of a unique dark component, the dark fluid, which is able to mimic the behaviour of both components. After a quick review of the cosmological constraints on this unifying dark fluid, we will present a model of dark fluid based on a complex scalar field and discuss the problem of the choice of the potential.

The cold diffuse interstellar medium (ISM) is turbulent withsupersonic, most likely transAlfvénic motions. All its tracers,including velocity, are structured down to the smallest scalesaccessible to observations. This structure, though, is not random andcan be quantified using the statistics of its Fourier phaseincrements. The quantity of structure of interstellar clouds is largerthan that of fractal Brownian motion (fBm) fields and of mildlycompressible turbulence. We propose that this structure is a responseof the medium to a general property of turbulence, the space-timeintermittency of its dissipation. The bursts of turbulentdissipation, because they temporarily (over a few hundred years) andlocally heat the diffuse medium up to ~103 K, irreversiblymodify the subsequent thermal and chemical evolution of the gas.Preliminary models of such bursts predict chemical abundances andexcitation of a subset of molecules that are in agreement with theobservations. Timescales of the velocity fluctuations are shortenough to locally decouple the neutrals from the ionized species inthe diffuse medium and generate helical magnetic fields. Small scalefluctuations of the polarization properties of the diffuse ISM aretherefore expected.

Unprecedented astrometric accuracy of Gaia gives a unique opportunity to perform a suite of tests of fundamental physics. The tests range from a test of the Local Lorenz Invariance and the gravitational defection of light to measuring the mass of black hole candidates in certain compact binary systems with visible components. Gaia data can also be used to estimate the energy flux of the gravitational waves in certain frequency ranges.

It takes years of effort employing the best telescopes and instruments to obtain high-quality stellar photometry, astrometry, and spectroscopy. Stellar evolution models contain the experience of lifetimes of theoretical calculations and testing. Yet most astronomers fit these valuable models to these precious datasets by eye. We show that a principled Bayesian approach to fitting models to stellar data yields substantially more information over a range of stellar astrophysics. We highlight advances in determining the ages of star clusters, mass ratios of binary stars, limitations in the accuracy of stellar models, post-main-sequence mass loss, and the ages of individual white dwarfs. We also outline a number of unsolved problems that would benefit from principled Bayesian analyses.

Gaia will only achieve its unprecedented measurement accuracy requirements with detailedcalibration and correction for radiation damage. We present our Silvaco 3D engineeringsoftware model of the Gaia CCD pixel and two of its applications for Gaia: (1) physicallyinterpreting supplementary buried channel (SBC) capacity measurements (pocket-pumping andfirst pixel response) in terms of e2v manufacturing doping alignment tolerances; and (2)deriving electron densities within a charge packet as a function of the number ofconstituent electrons and 3D position within the charge packet as input to microscopicmodels being developed to simulate radiation damage.

Inclusion compounds made of a water ice network, clathrate hydrates, are investigated by infrared spectroscopy. Because they can trap important “guest” volatiles species, they may influence the equilibrium, exchange and flux of volatiles in many bodies of the solar system. Their spectroscopic behaviour at low temperature (10–200 K) are shown and the search for their signatures by comparison to solar system objects remote spectra are discussed.

This review presents basic equations for the solution of the NLTE radiative transferproblem for trace elements and methods for its solution are summarized. The importance offrequency coupling in radiative transfer in stellar atmospheres is emphasized.

I review recent results on the angular distribution of substructure in CDM halos. I show that the subhalo distribution isanisotropic and generally prolate with a long axis that is closely aligned with the long axis of the total mass distribution of the host halo. I show that the correlation between the subhalo distribution and the long axis of the host halo is strong both in dissipationless and dissipational gasdynamical simulations. More massive subhalos tend to be more strongly clustered along the major axis of the host halo reflecting filamentary accretion. The anisotropy of subhalos has potential implications for the interpretation of several observations. For example, I show that while the mean projected mass fraction in substructure in the central regions of CDM halos is fsub ≈ 0.4%, fsub is a strong function of projection angle and is ~6 times higher for projections nearly collinear with the major axis of the host.

Many are the proposed scenarios for the formation of the thick disk of the Milky Way,going from the merger with smaller galaxies to fast gas accretion in the early Universe.Crucial information on which was the dominant mechanism for the formation of the thickdisk and other Galactic components is encoded in the chemical properties of their stars.By comparing the chemical properties of bulge, thick and thin disk stars one can addressthe question of which, among the competing processes of dissipation, satellite accretionand radial migration, play the dominant role in the formation of the different Galacticcomponents. The main difficulty at present is that current data samples suffer fromselection biases. Gaia shall bring a quantum leap to the solution of this problem, byproviding fiducial samples of the different galactic components with both, chemical andfull kinematic information. To pave the road for Gaia, theoretical models need to beimproved by taking into account both chemistry and dynamical aspects. A work of this kindis underway in Geneva Observatory.

By construction, optical (and near-infrared) interferometers typically have resolutions designed to resolve stellar and circumstellar features. Therefore gaging the point-source response of the interferometer in its operating environment is critical to the scientific interpretation of data from these devices. This is typically performed with observations of calibration sources that are modeled to be simple and quasi-unresolved by the interferometer. Herein I will discuss the goals and strategies for and issues with the selection of objects to serve as calibration sources for optical interferometry visibility measurements.

This paper presents the use of marked point processes for studying the galaxy distribution in our Universe. The methodology we propose has a general character and it is based on the following tools: summary statistics, stochastic modelling, simulation algorithms and statistical applications.

We present new results of a long-term investigation of the stellar content of the Large and the Small Magellanic Cloud. The main aim of the project is to obtain a comprehensive knowledge of the star formation history of these two nearby galaxies. Here we discuss the latest findings obtained using new data and a variety of different observational approaches, based on wide-field ground-based photometry and low-resolution CaT spectra. We find evidence of two main star formation events across the LMC disk. We also found evidence that the young and intermediate age population (<5 Gyr) presents a steeper gradient with radius than the old one (>8 Gyr). In particular, the young (<2 Gyr) component seems to extend to 8 degrees from the center, distance at which it decreases abruptly. At larger distance, the old population dominates, extending to at least 13.5 kpc. We also report the discovery of a population of stars located across the Magellanic Bridge, compatible with the old population of the LMC.

For more than ten years, a collaboration of European scientists has been producingsimulations of the Gaia mission. These simulations range from detailed realistic simulatedCCD images to large volume simulations of the Gaia telemetry.

The data of this decade of simulations has been used for many purposes: instrumentdesign, data processing software testing and validation, prediction of missionperformances, etc. Today the launch date is getting closer and the task of the simulatorin the mission preparation will be wrapped up in a couple of years.

However, this is not the end of the story since the Gaia simulator can also be used forthe preparation of the scientific exploitation of the Gaia data. In this talk we willpresent the simulator and its components, the data it can produce and the perspectives forthe utilisation of this data during the mission, both for data evaluation and scientificexploitation.

We start by looking at some recent developments in field measurements in middle main sequence and pre-main sequence stars. Then we consider how other magnetic effects such as the Hanle effect and continuum polarisation may be used to detect fields in a variety of stellar environments such as the solar corona and white dwarf atmospheres. Finally we consider how the current body of observational knowledge about magnetic stars may be integrated into a roughly coherent, provisional scenario of field origin and evolution.

We describe a prototype instrument built to validate the principleof the dispersed speckle method (Borkowski et al. 2002;Borkowski et al. 2004). This prototype, still under test, is aspectrograph where the multiple pupil, highly reduced in size,replaces the slit. An array of optical wedges is added near thegrating to separate the spectra from each speckle. Thefabrication and properties will be explained.