We present new developments on the cosmic-ray driven, galactic dynamo, modeled by means of direct, resistive CR–MHD simulations, performed with ZEUS and PIERNIK codes. The dynamo action, leading to the amplification of large–scale galactic magnetic-fields on galactic rotation timescales, appears as a result of galactic differential rotation, buoyancy of the cosmic-ray component and resistive dissipation of small–scale turbulent magnetic-fields. Our new results include demonstration of the global–galactic dynamo action driven by cosmic-rays supplied in supernova remnants. An essential outcome of the new series of global galactic dynamo models is the equipartition of the gas turbulent energy with magnetic-field energy and cosmic-ray energy, in saturated states of the dynamo on large galactic scales.

Galactic globular cluster (GC) stars exhibit abundance patterns which are not shared by their field counterparts, namely the well-documented C-N, O-Na and Mg-Al anticorrelations. Recent observations provided compelling evidence that these abundance anomalies were already present in the intracluster gas from which the presently observed stars formed. A widely held hypothesis is that the gas was polluted early in the history of the GC by material processed through H-burning at high temperature and then lost by stars more massive than the observed long-lived stars. However the “polluters" have not been unambiguously identified yet. Most studies have focused on AGB stars, but rotating massive stars present an interesting alternative. Here we critically analyse the pros and cons of both potential stellar polluters. We discuss the constraints that the observational data bring on stellar nucleosynthesis and hydrodynamics as well as on nuclear reaction rates and we try to answer to the following question: “Are GC ideal laboratories to test stellar nucleosynthesis and hydrodynamics?"

Although the theoretical study of very low metallicity (Z) and metal–free stars is not new,their importance has recently greatly increased since two related fields have been developing rapidly. The first iscosmological simulations of the formation of the first stars and of the reionisation period. The second is the observations of extremely metal poor stars. In this paper, we present pre–supernova evolution models of massive rotating stars at very low Z (Z = 10-8) and at Z = 0. Rotation has astrong impact on mass loss and nucleosynthesis. Models reaching break–upvelocities lose up to ten percents of their initial mass.In very low Z models, rotational and convective mixing enhancessignificantly the surface content in carbon, nitrogen and oxygen (CNO)when the star becomes a red supergiant. This induces a strong massloss for stars more massive than about 60 M๏. Our models predict typeIb,c supernovae and gamma–ray bursts at very low Z. Rotational mixingalso induces a large production of CNO elements, in particular ofprimary nitrogen. The stellar wind chemical composition is compatible with themost metal–poor star know to date, HE 1327–2326, for CNO elements. Ourmodels reproduce the early evolution of nitrogen in the Milky Way.

Convenient and accurate expressions for the radiative flux deep inside an arbitrarily shaped, differentially moving, optically thick medium are derived. Spectral lines are included either ina deterministic way or stochastically by assuming a Poisson point process. It is shown that the lines lead to decreasing fluxes when in the medium the absolute value of the velocity gradient is increased. The flux vector needs no longer to be parallel to the temperature gradient in contrast to the radiative acceleration, which to a very good approximation is not influenced by lines. Formulae for the corresponding mean values of the opacity are presented and discussed.

Our goal is to assess Gaia’s performance on the period recovery of short period(p < 2 hours) and small amplitude variability. To reach thisgoal first we collected the properties of variable stars that fit the requirementsdescribed above. Then we built a database of synthetic light-curves with short period andlow amplitude variability with time sampling that follows the Gaia nominal scanning lawand with noise level corresponding to the expected photometric precision of Gaia. Finallywe performed period search on the synthetic light-curves to obtain period recoverystatistics. This work extends our previous period recovery studies to short periodvariable stars which have non-stationary Fourier spectra.

Extrasolar planet searches blossomed and prospered under the auspices of the radial velocity method. However, efficient as it is, it can misinterpret a periodic signal created by stellar phenomena as being originated from a planet. The most common of these is the presence of a cold spot, frequent in active stars. Here we review the representative cases of HD 166435, GJ 674 and TW Hya and the different methods used to pinpoint the spots' presence. We finish by underlining the importance of infrared measurements, as done in the TW Hya campaign, as a way of reducing the effect of spots on radial velocity measurements to a negligible level.


We present the Far Infrared Telescope project submitted to the micro satellite programme of CNES and initially combined to a γ raymission. Millimeter wave emission from MeV-electrons is now wellknown, and on very few occasions non solar dedicated γ raydetectors have revealed emission from electrons at still higherenergies. The combination of two diagnostics: relativisticelectrons-synchrotron radiation in the far infrared and Bremsstrahlungat γ ray would probe electrons at energies above 10 MeV with100 ms time resolution, yielding unique information on the yet unknownhigh energy cut-off of the electron spectrum, and on the responseof the high photosphere to energy input during flares. We emphasizethe opportunity to observe solar flares in far infrared bands andto test uncooled detectors at the ground based station dome C in Antarctica.


The magnetic field of T Tauri stars is believed to be strong enough to disrupt the inner region of their accretion disk. At the inner disk edge, matter flows along the magnetic field lines at free fall velocity and accretes at the magnetic poles onto the star yielding hot accretion shocks on the stellar surface. I review the observational evidence supporting this magnetospheric accretion process in T Tauri stars and highlight recent results which point to a highly dynamic and time variable interaction between the inner disk and the stellar magnetosphere on timescales ranging from hours to months.

We show that the XCO factor, which converts the CO luminosityinto the column density of molecular hydrogen has similar values for dense, fullymolecular gas and for diffuse, partially molecular gas. We discuss the reasons of thiscoincidence and the consequences for the understanding of the interstellar medium.

Interferometry in the visible now provides milliarcsecond spatial resolution and thus has been intensely used for studying the circumstellar environment of evolved and pre-sequence stars. Up to now, most of the scientific results were obtained using only the modulus of the visibility as a function of baseline, time or projected baseline (the so-called "super-synthesis" effect). In this paper we will try to show that even without images, the phase of the visibility is able to put very strong constraints on stellar modeling since it is possible to achieve μarsecond measurements using this technique. We will illustrate through two examples from the GI2T interferometer how the modulus and the phase of the visibility were used to understand the physics of Be disks. We will stress on the importance and the potential of coupling high angular resolution with high spectral resolution for the study of stellar physics. Finally, We will present a possible study on the phase signatures due to stellar rapid rotation that can be done using the VLTI interferometer.

I describe aspects of the non-solar astronomyuse of Dome C telescopes under daytime/summerconditions. In the thermal IR (TIR) wavelengthregion, where scattered sunlight is dwarfed bysky and facility radiation, astronomy benefitsfrom the better seeing, continuous sky coverage,a more than doubling of the observing time andthe improved site accessibility and logistics.Na-Laser Guide Stars (LGSs) can be used forwavefront sensing in daytime using very narrowband filters to suppress the sky background atvisible wavelengths. It enables the use ofAdaptive Optics for diffraction limited imagingin the TIR during daytime at Dome C.

This report provides the recommendations of ARENA Working Group 1 concerning the development of and objectives for a wide-field, optical/infrared, 2.5 m class telescope for Antarctica. It discusses the key science drivers for such a telescope, the performance and capabilities it should have, and the logistics and infrastructure issues relevant to its construction and operation.

Most of the mass of the interstellar medium is in neutral phases that are heated by far-ultraviolet radiation from star forming regions. The gas, in turn, emits line radiation in the infrared and submillimeter that potentially has great diagnostic value. In this paper, we will review the physical processes (including heating, cooling, gas phase and grain surface chemistry) that give rise to this line emission and present diagnostic diagrams. We will also discuss several examples where models of neutral gas emission have been used to interpret line emission, including observations of H2O and O2 in molecular clouds and an example which points out the caution that must be used when applying the diagnostics to kiloparsec-sized regions in other galaxies.

21-cm studies of the Galactic extra-planar gas layer can help us understand the origin of the gaseous Galactic halo and its interaction with the Milky Way disk. The 100-m Effelsberg radio telescope was utilized to detect and analyze a population of Hi halo clouds belonging to this layer, at Galactocentric radii R > 8.5kpc, following Galactic rotation. This sample of clouds has similar properties to the population detected by Lockman with the GBT at R < 8.5kpc. High resolution follow-up observations resolve them into a number of small, dense, cold arc-minute sized Hi cores. Their study provides evidence for a thermal equilibrium with the extended warmer envelopes. Single dish observations with the 300-m Arecibo telescope disclosed a sample of Hi clouds with similar properties. A power spectrum analysis of the Arecibo maps probes the characteristics of turbulence as a dominant physical process in the halo region.

We present the first determination of fundamental parameters (positions, reddenings, distances, ages and kinematics) for a sample of 22 open clusters in the solar vicinity. A systematic search for unknown open clusters using the astrometric and photometric data included in the Tycho2 catalogue has resulted in the identification of several candidates. In this work, we introduce 11 of the most promising open cluster candidates. The reality of the stellar aggregates is supported by the analysis of proper motions, colour-magnitude diagrams, stellar density distributions, and by the visual inspection of the Digitised Sky Survey (DSS) plates. The proper motion data included in the Tycho2 catalogue has also allowed us to identify members in 11 open clusters for which no information, besides their positions and estimates of their apparent diameters, was previously available. Reddenings, distances and ages were determined for most objects using colour-magnitude diagrams for cluster members, built using the photometry included in Tycho2, complemented by spectral types found in the literature. We find that the majority of the aggregates are nearby (closer than ~500 pc) open clusters.

Silicates form a major component of cosmic dust. This paper summarizes the main structural and spectroscopic properties of amorphous and crystalline silicates. Furthermore, it reviews our knowledge of cosmic silicates in the Galaxy. Recent in-situ studies of presolar silicates extracted from primitive meteorites and anhydrous interplanetary dust grains will be discussed.

The Gattini cameras are two site testing instruments for the measurement of optical sky brightness, large area cloud cover and auroral detection of the night sky above the high altitude Dome C site in Antarctica. The cameras have been operating since installation in January 2006 and are currently at the end of the first Antarctic winter season. The cameras are transit in nature and are virtually identical, both adopting Apogee Alta CCD detectors. By taking frequent images of the night sky we obtain long term cloud cover statistics, measure the sky background intensity as a function of solar and lunar altitude and phase and directly measure the spatial extent of bright aurora if present and when they occur. The full data set will return in December 2006 however a limited amount of data has been transferred via the Iridium network enabling preliminary data reduction and system evaluation. An update of the project is presented together with preliminary results from data taken since commencement of the winter season.

This is a brief summary of the 2nd ARENA conference, including statistical information and a short review of the talks. The conference ended up with the creation of 6 working groups aimed at preparing the final ARENA roadmap in the fields of astronomy and astrophysics where Antarctic atmospheric conditions at Dome C could lead to compelling scientific breakthroughs. The results of their reflections and recommendations will be presented at the third and final ARENA conference to be held in May 2009.

Preliminary abundances of lithium and a few other elements have been obtainedfor 31 field Am stars with good Hipparcos parallaxes, as well as for36 normal A and F stars. Radial and projected rotational velocities were determined as well. We examine the Li abundance as a function ofthe stellar parameters: for normal stars, it is clearly bimodal forTeff < 7500 K, while Am-Fm stars are all somewhat Li-deficientin this range. The most Li-deficient stars – either Am or normal – tendto be at least slightly evolved, but the reverse is not true.

The growing awareness of the importance of the fossil record in the Milky Way forconstraining galaxy formation theory is reflected by the increasing number of new ground-and space-based surveys designed to unravel the formation history of the Galaxy. Recently,a new kinematic survey has been produced by means of spectro-photometric data from theSloan Digital Sky Survey (SDSS-DR7) and high-quality proper motions derived frommultiepoch positions from the Guide Star Catalogue II (GSC-II). In this framework, weassembled a sample of ~ 30 000 FGK nearby metal-poor (sub)dwarfs for whichselection and distance estimates take advantage of accurate stellar atmospheric parameters(effective temperature, surface gravity and metallicity) derived from SDSS spectra. Here,as one of the most interesting applications of this catalogue, we consider the feasibilityof probing fossil signatures of the formation of the Milky Way by selecting and analysingsubsamples of stars as tracers of the seven-dimensional space distribution (fullphase-space coordinates plus chemical abundance) of the Galactic halo population within afew kiloparsecs from the Sun. Preliminary results exhibit statistical evidence fordiscrete overdensities localised in kinematics and in the space of adiabatic invariants(angular momentum and energy). By examination of their intrinsic properties, we suggestthat they may be possible fossil signatures of past mergers or other accretion events.