The Very Large Telescope Interferometer on Cerro Paranal in Northern Chileis one of the largest optical facilities used in astronomy.It can combine two or three of the four 8.2 m and four movable 1.8 m telescopes,which span baselines between 8 and 202 m.Observations are carried out in the near- and mid-infrared, covering thewavelength range from 1 to 13 μm.


Binary neutron star merger lead to the formation of amassive, rapidly and differentially rotating neutron star (or astrange star) or to the prompt collapse to a black hole. The maximummass of a differentially rotating remnant is crucial for distinguishingbetween these two final objects. We study the effect of differentialrotation on the maximum mass of neutron stars (strange stars). Wenumerically construct stellar models using a highly accuraterelativistic code based on a multi-domain spectral method. We findmuch larger mass increases for strange stars than for neutron starsfor the same degree of differential rotation.

A nonlinear radiative pulsating model for the long-periodic Cepheid l Carinae is presented. The LTE metallic lines and non-LTE hydroen lines are calculated and compared with the HARPS observations. We found that the weak and medium metallic lines well correspond to the radial Cepheid pulsation, while the Hα and some other strong lines reveal very strange behaviour which is not consistent with usual Cepheid pulsation. We conclude that l Car must have an extended circumstellar envelope, and discuss its possible parameters.

So far our understanding of the evolution of the ISM has beenscanty, because of the inherent nonlinearity of all the processesinvolved. Modelling the interstellar medium in galaxies in aself-consistent way requires an approach that must take into accountthe relevant scales, which may cover several orders of magnitude(e.g., from kpc to less than 1 pc). This is a difficult task thatrequires the use of sophisticated numerical codes, adequatecomputing power, and precision input data from observations. Thelarge range of scales can be resolved by means of adaptive meshrefinement (AMR), that is, the grids reproducing the computationaldomain are refined on the fly such that a minimum number of cells isneeded to provide the most complete description of the flow.
In this paper we review the most recent results on 3D modeling ofthe interstellar medium and disk-halo interaction in a section ofthe Milky Way that includes the Galactic magnetic field, backgroundheating due to starlight, self-gravity and allows for theestablishment of the duty-cycle between the disk and halo (commonlyknown as galactic fountain) by using a grid that extends up to 10kpc on either side of the midplane. Our simulations capture both thelargest structures (e.g., superbubbles) together with the smallerones (e.g., filaments and eddies) down to 0.625 pc. We investigate,among other things, the variability of the magnetic field in theGalactic disk and its correlation with the density, the rôle ofram pressure in the dynamics of disk gas and the relative weight ofthe ram, thermal and magnetic pressures, the mass distribution andthe volume filling factors of the different temperature regimes inthe ISM, as well as the scales at which energy is injected into theinterstellar turbulence and we give an estimate for the dimension ofthe most dissipative structures.

Concordia has been the third permanent station inland the Antarctic continent since February 2005. It was built jointly by France and Italy in order to offer to the scientific community a platform for research on the antarctic plateau, high in altitude. After the very successful drilling programme EPICA at Dome C, an European project gathering 10 countries and offering the oldest accurate climate archive, many other field of science will benefit from the exceptional properties of the site, namely astronomical researches. This paper provides information on these properties and on the current facilities in terms of building and transport. In addition, it points out the environmental protection and waste management in force at Concordia, in agreement with the Antarctic Treaty and Madrid Protocol.

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.

We present an update on the performance of our 2 mm bolometer camera GISMO (the Goddard IRAM 2 Millimeter Observer), which is used for astronomical observations at the IRAM 30 m Telescope. The camera is optimized to efficiently observe dusty high-redshift galaxies. GISMO uses a monolithic 8 by 16 Backshort Under Grid (BUG) array with superconducting Transition Edge Sensors (TES). It serves as a testbed for our close-packed superconducting bolometer technologies and guides us in optimizing the design of future fast, low background bolometer cameras. Illustrated by astronomical observations we obtained recently, we demonstrate the scientific potential of the camera, highlighted by the detection of two high redshift galaxies.

The existence of coronal plasmoids has been postulated for many years in order to supply material to streamers and possibly to the solar wind (SW). The W-L SoHO C2 Lasco coronagraph observations were made under the 2.2 solar radii (R0) occulting disk to look at the ultimate sources of the SW; EUV imagers are preferably devoted to the analysis of the corona on and very near the solar disk. Here, in addition to eclipse white-light (W-L) snapshots, we used the new SWAP space-borne imager designed for the systematic survey of coronal activity in the EUV lines near 17.4 nm, over a field of view (FOV) up to 2 R0. Using summed and co-aligned images, the corona can then be evaluated for the 1st time up to the limit of this FOV. At the time of the July 11, 2010, solar total eclipse a 20h continuous run of observations was collected, including images taken during eclipse totality from several ground observing locations where W-L data were collected. A plasmoid-like off-limb event was followed using the SWAP summed

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.

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.

The extreme cleaning of stellar images, needed for distinguishing their planets and especially those analogous to the Earth, requires coronagraphy and apodization. These techniques suppress the diffraction rings, but not the residual speckles resulting from the bumpiness of the optical surfaces.Several methods, coherent and incoherent, can in principle remove these speckles, but some of them are affected if the star is slightly resolved. With the future large hypertelescopes, spanning 100 kilometers or more to resolve the details of exo-Earths, this could require cleaning procedures applied separately for each sub-aperture before recombining the beams.

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.

We present color-magnitude diagrams (CMD) reaching the oldest main sequence turn offs for three fields in the Fornax dwarf spheroidal galaxy, obtained with FORS1 at the VLT. One of them is situated at the center of the galaxy while the other two are located at a distance of 10′ form the center. We determine the full star formation history (SFH) of the central field, extending to the first star formation events.

We discuss the properties of extrasolar planets inferred fromobservations and theoretical models. We show that COROT should be ableto usefully constrain the albedos of extrasolar planets with shortorbital periods, given levels of stellar variability close to that ofthe Sun. We sketch possible strategies for observational astrophysicalprograms using high contrast imaging.

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 atmospheric boundary layer contribution to the total seeing atDome C is presented in this paper. With a mean value of0.07'', this is one of the most stable boundary layerencountered. We discuss the temporal evolution of this part of theatmosphere and its relationship with meteorological parameters. Inwinter, the combined effects of the low wind speeds and low inversionlayer translate to the creation of little thermal turbulence above30 m.

We formulate the relation between the beam pattern and the source confusion limit.In the formula for the general number counts, the upper cutoff of the integration is set to obtain a numerically reasonable result.The upper cutoff corresponds to the beam area, so we input the beam pattern as the two-dimensional array of the Point Spread Function (PSF).Based on the representative number counts, we evaluate the source confusion typical of various infrared spacecrafts (e.g. ASTRO-F[1]).

In this communication, we analyze the possibility of detectingexoplanets using shaped and apodized apertures alone (withoutcoronagraphy) for the case of a perfect telescope operated inspace. In a first section, after a brief introduction to thetheory of diffraction and the determination of several usefulparameters, we show that the effects of shaped and apodizedaperture can be presented in an unified manner, making use of theRadon transform of the aperture of the telescope. This permits asimple comparison of the techniques of apodization and apertureshaping between them. An illustration of this approach is madefor a few apertures. In a second section, we introduce thesemi-classical theory of photodetection. Using simplificativeassumptions, we derive signal-to-noise ratio (SNR) expressions anddraw the corresponding curves for an experiment using a circulartelescope apodized by a prolate spheroidal function. We found thatfor given condition there is an apodization that can optimize theSNR. This apodization is generally a very strong one.

In order to increase in Spain the social interest in the study of interplanetary matter (asteroids, comets and meteoroids) we created the Spanish Photographic Meteor Network (SPMN) in 1997. This network has been dedicated to studying interplanetary matter with participation of researchers from three universities (Universitat Jaume I, Universitat de Barcelona and Universitat de València), the Institut d'Estudis Espacials de Catalunya (IEEC) and the Instituto de Astrofísica de Andalucía and it is also supported by the Atmospheric Sounding Station at El Arenosillo (INTA-CEDEA) and by theExperimental Station La Mayora (EELM-CSIC). In order to promote the participation of amateurs, our homepage (www.spmn.uji.es) presents public information about our research explains how amateur astronomers can participate in our network. In this paper we give some examples of the social role of a Fireball Network in order to give a coherent explanation to bright fireball events. Moreover, we also discuss the role of this kind of research project as a promoter of amateur participation and contribution to science. In fact, meteor astronomy can become an excellent area to form young researchers because systematic observation of meteors using photographic, video and CCD techniques has become one of the rare fields in astronomy in which amateurs can work together with professionals to make important contributions. We present here some results of the campaigns realized from the formation of the network. Finally, in a new step of development of our network, the all-sky CCD automatic cameras will be continuously detecting meteors and fireballs from four stations located in the Andalusia and Valencian communities by the end of 2005. Additionally, during important meteor showers we plan to develop fireball spectroscopy using medium field lenses.

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.