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]).

Recent observations show that the number of stars with very lowmetallicities in the dwarf spheroidal satellites of the Milky Way islow, despite the low average metallicities of stars in these systems. Weundertake numerical simulations of star formation and metal enrichmentof dwarf galaxies in order to verify whether this result can bereproduced with ”standard” assumptions. The answer is likely to benegative, unless some selection bias against very low metallicity starsis present in the observations.

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.

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.

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.

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.

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 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.

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.

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.

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.

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.

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.

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.

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.

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.

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.