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.

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.

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.

Debris disks are dusty and/or gasous disk that are viewed in scattered light and thermal emission around stars around 107–108 yr. It is well known that the dust in these system is not primodial. It is short lived and must be continuously replenished by colliding planetesimals. Most of them appear distorted by the gravitational pertubations by inner planets or stellar companions. This is why these systems are viewed today as young planetary systems. 
Debris disks are collisional systems. Thanks to collisional cascade towards smaller size, the dust particles are transported outwards by radiation or stellar wind pressure. Below a given blow-off size they escape the system. This model explains the radial density profiles observed.
The various asymmetries, clumps and other dynamical structures such as spiral arms are though to originate in gravitational perturbations by planets and/or companions. Planets usually create gaps in disks, but they also sculpt disks via their mean-motion resonances. Clumpy structures are often invoked as resulting from such an interaction. Stellar companions usually truncate the disk, sometimes confining them to thin annular structures. They also help creating spiral patterns, either tidally or by secular interaction. In this context, the situation is different whether the perturbing companions are bound or just passing stars. In any case, dynamical studies (often specific to each system) can greatly help constraining the configuration and the past history of these systems.

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.

We present a preliminary data release from our multi-year campaign at Keck Observatory tostudy the host galaxies of a large sample of Swift-era gamma-ray bursts via multi-colorground-based optical imaging and spectroscopy. With over 160 targets observed to date (andalmost 100 host detections, most of which have not previously been reported in theliterature) our effort represents the broadest GRB host survey to date. While targetingwas heterogeneous, our observations span the known diversity of GRBs including shortbursts, long bursts, spectrally soft GRBs (XRFs), ultra-energetic GRBs, X-ray faint GRBs,dark GRBs, SN-GRBs, and other sub-classes. We also present a preview of our database(currently available online via a convenient web interface) including a catalog ofmulti-color photometry, redshifts and line ID’s. Final photometry and reduced imaging andspectra will be available in the near future.

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]).

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.

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.

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.

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.

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.

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

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.

Using simplificative assumptions, we show that a redundant configuration of diluted apertures should permitan easier exoplanet detection than a non-redundant one. This result assumes that after coronagraphy theplanet appears over an uniform background whose statistical fluctuation is the unique source of noise. Thedetection is made using a matched filter, cross-correlating the observed image with the telescope array PSF.In that case, the relevant parameter appears to be the integral of the modulus squared of the aperture MTF.

The Gaia Attitude Model (GAM) is a simulation package that is developed to achieve adetailed understanding of the Gaia spacecraft attitude. It takes into account externalphysical effects and considers internal hardware components controlling the satellite. Themain goal of the Gaia mission is to obtain extremely accurate astrometry, and thisrequires a good knowledge of Gaia’s behaviour as a spinning rigid body under the influenceof various disturbances.

In a first part the paper reviews some of the major Spitzer legacy imagingsurveys to show the quantity of data available, and the subsequent need forspectroscopic follow-up surveys on equivalent wide fields. They arerequired for many science cases, as giant star forming regions, youngplanetary nebulea, the Galactic Centre, nearby galaxies, distant galaxyclusters. This capability of wide, integral field spectroscopy, missing inall the existing and planned astronomical facilities, thus, appears amongthe most pertinent choice for the future of astronomy at Dome C. For theinstrumental solution, aflexibility in the choice of spectral resolution and spectral domain on abroad infrared range is desirable to be able to undertake a large variety of study, onextragalactic and galactic fields as well. This capability can be only offered byan Imaging FTS. It fully benefits from the low thermal backgroundemission of Dome C, particularly in the 1.8 to 5.5 μm range, and reachan optimum sensitivity by imaging emission lines. In a difficult site asDome C, a dedicated, medium-size telescope would be the most effective wayof exploiting such an instrument.

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.

Gaia, a cornerstone ESA mission, will produce a three-dimensional map of our Galaxy. It was launched in December 2013, and it is expected to provide an important improvement in our understanding of the structure, composition and evolution of the Galaxy. During its five years of data collection, Gaia is expected to transmit to Earth some 150 terabytes of raw data, producing a catalogue of some 109 individual objects. After on-ground processing the full catalogue is expected to be in the range of one to two petabytes of data. Preparation for the explotation of this huge amount of data is essential, and work is being undertaken to model the expected output of Gaia in order to predict the content of the Gaia catalogue and to facilitate the production of tools required to effectively analyse the data. Therefore, the Gaia Data Processing and Analysis Consortium (DPAC) has developed a set of simulators, including a simulator called the Gaia Object Generator (GOG), which simulates the end of mission and the epoch transit catalogues, including observational errors. In 2014, CU2 has delivered a GOG end of mission catalogue, containing the potential single star observable population (with G < 20 mag) using the Gaia Universe Model, showing the effect of the observational errors. The GOG catalogue is actively used inside CU9, which is responsible for providing access to the Gaia data to the scientific community through the Gaia archive. GOG has a direct impact in the Gaia real catalogue production, as the simulated Gaia data will be used to detect false-positives and a biased data set to validate that problems can been found. Moreover, GOG simulations will be used also to test the software which will maintain and preserve all the versions of the catalogue, and to become familiar with working with such a large and rich dataset.