The European Space Agency is building a space telescope to observe the Universe in the Far-IR and sub-millimeter regime of the electromagnetic spectrum. The scientific payload is composed of three instruments. One of them, PACS, is equipped with a novel type of bolometer arrays developed by CEA in the late 90's. We briefly present the PACS Photometer and the architecture of CEA filled bolometer arrays. We accessed the physics of the detectors and thoroughly measured their performances by developing a pragmatic calibration procedure. The Photometer is now calibrated and integrated on the focal plane of the observatory. The launch is scheduled for April 2009. Meanwhile, CEA is working on adapting PACS bolometers to longer wavelength for wide-field ground-based telescopes, and for the future cold-telescope space mission SPICA.

We present wind and temperature profiles at Dome C measured during thepolar summer by balloon born sonds. Data from 197 flights have beenprocessed for 4 campaigns between 2000 and 2004. We show theexceptionnal wind conditions at Dome C: averaged ground wind speed is 3.6 m s-1. We noticed in mid-november the presence of high altitude strong winds (40 m s-1) probably due to the polar vortex which disappear in summer. These winds seem to have no effect on seeing measurements made with a DIMM at the same period. Temperature profiles exhibit a minimum at height 5500 m (over the snow surface) that defines the tropopause. Surface layer temperature profile has negative gradient in the first 50 m above ground in the afternoon and a strong inversion layer (5°C over 50 m) around midnight. Wind profiles are compared with other astronomical sites, and with a meteorological model from Meteo France.

EURECA (European Underground Rare Event Calorimeter Array) is an astro-particle physics facility aiming to directly detect galactic dark matter. The Laboratoire Souterrain de Modane has been selected as host laboratory. The EURECA collaboration unites CRESST, EDELWEISS and the Spanish-French experiment ROSEBUD, thus concentrating and focussing effort on cryogenic detector research in Europe into a single facility. EURECA will use a target mass of up to one ton, enough to explore WIMP – nucleon scalar scattering cross sections in the region of 10-9 – 10-10 picobarn. A major advantage of EURECA is the planned use of more than just one target material (multi target experiment for WIMP identification).

We show, by means of a perturbative weakly nonlinear analysis, that the axisymmetric magneto-rotational instability (MRI) in a magnetic Taylor-Couette (mTC) flow in a thin-gap gives rise, for very small magnetic Prandtl numbers $({\cal P}_{\rm m})$, to a real Ginzburg-Landau equation for the disturbance amplitude. The saturation amplitude As is found to scale in this regime as ${\cal P}_{\rm m}^\delta$, with 1/2 < δ < 2/3 (depending on the boundary conditions adopted). The asymptotic results are shown to comply with numerical calculations performed by using a spectral code. They suggest that the transport due to the nonlinearly developed MRI may be vanishingly small for ${\cal P}_{\rm m} \ll$ 1.

One can solve the Jeans equation analytically forequilibrated dark matter structures, once given two pieces of inputfrom numerical simulations. These inputs are 1) a connection betweenphase-space density and radius, and 2) a connection between velocityanisotropy and density slope, the α – β relation. The first(phase-space density vs. radius) has been analysed through severaldifferent simulations, however the second (α – β relation) has notbeen quantified yet. We perform a large set of numerical experimentsin order to quantify the slope and zero-point of the α – βrelation. This allows us to conclude that equilibrated dark matterstructures indeed have zero central velocity anisotropy,central densityslope of α0 ≈ –0.8, and outer anisotropy ofapproximately β∞ ≈ 0.5.

The number of detections as well as significantly deep non-detections of optical/NIRafterglows of Type I (compact-object-merger population) Gamma-Ray Bursts (GRBs) has becomelarge enough that statistically meaningful samples can now be constructed. I presentwithin some recent results on the luminosity distribution of Type I GRB afterglows incomparison to those of Type II GRBs (collapsar population), the issue of the existence ofjet breaks in Type I GRB afterglows, and the discovery of dark Type IGRBs.

This paper describes our strategy and presents the specific additional calibration tool added to the near-infrared focal instrument AMBER of the Very Large Telescope Interferometer, to achieve the direct detection of extrasolar planets with color-differential interferometry. The measurement of the angular orbits, masses and spectra of hot giant extra solar planets can be achieved for Jupiter size planets up to 0.2 a.u. away from a 10 pc distant star, if it is limited only by photon, detector and background noises. However, this requires an extremely good control and calibration of the atmospheric and instrumental stability.

The MIMAC project is multi-chamber detector for Dark Matter search, aiming at measuring both track and ionization with a matrix of micromegas μTPC filled with 3He and CF4. Recent experimental results on the first measurements of the Helium quenching factor at low energy (1 keV recoil) are presented.

Solar magnetic fields evolve on many time-scales, e.g., thegeneration, migration, and dissipation of magnetic flux during the 22-yearmagnetic cycle of the Sun. Active regions develop and decay over periods ofweeks. The build-up of magnetic shear in active regions can occur within lessthan a day. At the shortest time-scales, the magnetic field topology can changerapidly within a few minutes as the result of eruptive events such as flares,filament eruptions, and coronal mass ejections. The unique daytime seeingcharacteristics at Dome C, i.e., continuous periods of verygood to excellent seeing during almost the entire Antarctic summer, allow us toaddress many of the top science cases related to the evolution of solarmagnetic fields. We introduce the Advanced Solar Photometric Imager andRadiation Experiment and present the science cases for synoptic solarobservations at Dome C. Furthermore, common science cases concerningthe solar-stellar connection are discussed in the context of the proposedInternational Concordia Explorer Telescope.

This paper serves as an introduction to the current book. It provides the basic notions of long-baseline optical/infrared interferometry prior to reading all the subsequent chapters, and is not an extended introduction to the field.

Analytical and numerical solutions of the radiative transfer equation recently obtained in Heidelberg are reviewed. In particular, a multidimensional finite-element algorithm for unstructured grids that can be adaptively refined is discussed in detail.

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.

Accretion onto a compact object must occur through a disc when thematerial has some initial angular momentum. Thin discs and the thickerlow radiative efficiency accretion flows (LRAFs) are solutionsto this problem that have been widely studied and applied. This is anintroduction to these accretion flows within the context of X-raybinaries and cataclysmic variables.

These lectures attempt to expose the most important ideas, which have been proposed to explain the formation of stars with particular emphasis on the formation of brown dwarfs and low-mass stars. We first describe the important physical processes which trigger the collapse of a self-gravitating piece of fluid and regulate the star formation rate in molecular clouds. Then we review the various theories which have been proposed along the years to explain the origin of the stellar initial mass function paying particular attention to four models, namely the competitive accretion and the theories based respectively on stopped accretion, MHD shocks and turbulent dispersion. As it is yet unsettled whether the brown dwarfs form as low-mass stars, we present the theory of brown dwarfs based on disk fragmentation stressing all the uncertainties due to the radiative feedback and magnetic field. Finally, we describe the results of large scale simulations performed to explain the collapse and fragmentation of molecular clouds.

Due to their extreme luminosities, gamma-ray bursts (GRBs) can be detected in hostileregions of galaxies, nearby and at very high redshift, making them important cosmologicalprobes. The investigation of galaxies hosting long-duration GRBs (whose progenitor is amassive star) demonstrated their connection to star formation. Still, the link to thetotal galaxy population is controversial, mainly because of the small-number statistics:~1, 100 are the GRBs detected so far, ~280 those with measured redshift, and~70 the hosts studied in detail. These are typically low-redshift(z < 1.5), low luminosity, metal poor, and star-forming galaxies. Onthe other hand, at 1.5 < z < 4, massive, metal rich and dusty,interacting galaxies are not uncommon. The most distant population(z > 4) is poorly explored, but the deep limits reached point towardsvery small and star-forming objects, similar to the low-z population.This “back to the future” behavior is a natural consequence of the connection of long GRBsto star formation in young regions of the universe.

The inclusion of rotation in massive star models improves the agreement between theory and observations on at leastthree important points: 1) rotational mixing allows to produce variations of the surface abundances already during the Main-Sequence phase as is observed. The changes of the surface abundances are more important when, for a giveninitial velocity, the initial masses are larger, and/or the metallicities are lower; 2) the observed numberof red supergiants at the metallicity of the Small Magellanic Cloud (SMC) can be accounted for; 3) the observed variation of the number ratioof Wolf-Rayet to O-type stars as a function of the metallicity can be reproduced. For all these comparisonsnon-rotating models give unsatisfactory fits. Rotating models results also give interestinginsights on questions such as the origin of Be stars, the mechanisms responsible forthe huge mass loss rates undergone by the Luminous Blue Variables, the rotation ratesof pulsars, the progenitors of collapsarsand the sources of primary nitrogen at low metallicity.

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.

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.

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.

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.