Both emission and absorption techniques have been developed at the AILES beamline of SOLEIL synchrotron to record far infrared (FIR) spectra of transient species. To illustrate the possibilities offered by our absorption set-up, we report in this paper new rotational transitions of the SO radical falling in the spectral range covered by the HIFI spectrometer onboard Herschel.

This paper introduces the The Milky Way Unravelled by Gaia conference proceedings.

This work concerns the study of the properties of convective cores in main-sequence models of solar-like pulsators and what information they may hold about stellar ages. We verified that the maximum absolute frequency derivative of particular combinations of frequencies, which we name “the slopes”, provides information on the relative size of the discontinuity in the sound-speed profile at the border of the convectively mixed region. Since the latter is related to the evolutionary state of stars, we show that for models with masses above 1.3M⊙, it may be possible to estimate the fraction of stellar main-sequence evolution from the slopes. Moreover, for models with masses below 1.2M⊙ we verified that it may be possible to use the slopes to discriminate against models with small amounts of core overshoot.

One of the fields in which teaching Astronomy is more demanded is non-formal education. The Stars Workshop we present in this contribution consisted on an introduction to Astronomy and observation methods. The main objectives were: to know the main components of the Universe, their characteristics and the scales of size and time existing between them; to understand the movement of the different celestial objects; to know the different observational techniques; to value the different historical explanations about the Earth and the position of Humanity in the Universe. This Stars Workshop was a collaboration with the Escuela de Tiempo Libre Jumavi, which is a school dedicated to the training and non-formal education in the leisure field.

The Sculptor dwarf Spheroidal is a Milky Way satellite with a dominant old (>10 Gyr) population that displays at least two distinct stellar populations. We present new sensitive imaging data from CTIO/MOSAIC and make a detailed study of the stellar populations of Sculptor, including the main sequence turnoff (MSTO) properties. We present the Star Formation History (SFH) and Metallicity Distribution Function (MDF) of the Sculptor dSph and find that a well-defined radial gradient is present not only in metallicity but now also in age.

Recent developments in coronagraphy have increased the reachable dynamic range limit of telescopes and thus opened the possibility for the imaging of fainter and fainter companions. They rely on a series of modifications of the original concept involving amplitude and phase masks in either the pupil or the image plane. They are designed to operate optimally at one wavelength. In this paper we first study the chromatic leakage in Pupil Apodised Lyot Coronagraphs and then present a theoretical solution that create a polychromatic null while maximizing the photon flux from the companion. Finally we discuss a promising experimental implementation of this solution using interferometric apodisations.

Atmospheric field experiments were made at the French-Italian station of Concordia at Dome C during several years. These experiments were limited to the summer season. In 2005 Concordia has become a permanent base, this allowed to carry out STABLEDC (STudy of the Atmospheric Boundary Layer Environmental at Dome C plateau station) that is an atmospheric field experiment of the duration of one year. The aim of STABLEDC was to study the processes occurring in the long-lived stable and the weak convective atmospheric boundary layers, observed during winter and summer, respectively, and to collect the relevant parameters for the atmospheric models. Both in situ and ground based remote sensing instruments have been used to monitor the meteorological parameters. The first part of the paper gives a brief illustration of the objectives of the field experiment, and a description of site and instrumentation. The second part shows the behaviour of some micrometeorological parameters: temperature, wind speed, sensible heat flux. The surface radiation balance components are also shown. Finally some experimental activities are proposed.

The gain of thermal infrared instruments in the 2–25 μm wavelength range from Antarctica is summarized by comparing three parameters: the ambient temperature; the atmospheric transparency, with perceptible water vapor content (PWV) in particular; and the image quality. For the 2 m class infrared telescope projects at Dome C the estimated mid infrared point source sensitivity can be compared to the sensitivities reached at 10 m class telescopes elsewhere. This comparison favors a thermal IR instrument at Dome C with focus on key science cases; two examples are: i) Survey type projects, such as mid infrared photometric imaging or spectro–polarization campaigns of YSO. Or ii) monitoring and rapid response observations on the Galactic Centre, the LMC, SN or GRB.

The technique of pupil densification bridges the gap existing betweenconventionnal optical astronomy observing techniques and opticalinterferometry: it indeed leads to the concept of hypertelescope: an instrument that can provide direct images at the focus of an interferometer.The hypertelescope is the open sesame for high dynamic imaging with aninterferometer: indeed, the elementary remapping of the pupil operated by adensifier not only maximizes the dynamic range and the signal to noise ratioof images but also makes the interferometer compatible with most existingcoronagraphic devices.Moreover, a careful discussion about field of view show that for a dilutedarray, the pupil densification preserves all the relevant high angular resolution information collected by the interferometer and therefore inducesno field loss.

Due to the non-commutation of spatial averaging and temporal evolution, inhomogeneities and anisotropies (cosmic structures) influence the evolution of the averaged Universe via the cosmological backreaction mechanism. We study the backreaction effect as a function of averaging scale in a perturbative approach up to higher orders. We calculate the hierarchy of the critical scales, at which 10% effects show up from averaging at different orders, observable up to scales of 200 Mpc. The cosmic variance of the local Hubble rate is 10% (5%) for spherical regions of radius 40 (60) Mpc. We compare our results to the Hubble Space Telescope (HST) Key Project data.

Hydrogenated amorphous carbons, an important component of the interstellar carbonaceous dust, possess infrared spectral signatures (at 3.4, 6.9 and 7.3 μm) that are ubiquitous in the diffuse interstellar medium of galaxies, but not observed in dense clouds. To better understand the role played by cosmic rays in the disappearance of these absorption bands, irradiation experiments of hydrocarbon dust analogues have been performed with different swift ions. The results obtained through the in situ infrared monitoring of the samples during the irradiations allow to infer the dehydrogenation effect of the cosmic ray distribution on the interstellar hydrogenated amorphous carbons. The importance of this interstellar dust destruction by cosmic rays is discussed in comparison to other energetic processes in different interstellar environments.

A very brief introduction to the theory of line broadening is presented.

We present the results of the first light of CORONA obtained during the summer campaign 2005 at Dome C. The CORONA experiment uses an automated 14'' antarctized telescope for its remote operation from the Concordia station. The instrument includes an Achromatized Phase Knife Coronagraph (APKC) with no tip-tilt correction. The high contrast long exposure is obtained from image selection among raw short exposures.

The observed brightness fluctuations and large-scale structures on thesurface of the Red Supergiant Betelgeuse make the star a prime targedfor future interferometric measurements. At the same time, they openthe possibility to resolve these structures in numerical radiationhydrodynamics simulations of the entire star. After some general remarksabout the possibility and difficulties of 3D simulations of stars ingeneral results of such calcuations of the outer convective envelope andthe atmosphere of a Red Supergiant and a star on the Asmyptotic GiantBranch are presented. These show that numerous short-lived small-scalesurface granules coexist with a few long-lived large-scale envelopeconvection cells. Pressure fluctuations deform the star and influencethe surface convection. The convective “granulation" pattern differsfrom the solar one. Convection and pulsations produce large-scalehigh-contrast brightness fluctuations that might explain the observedluminosity variations and surface “spots”. Shock waves and supersonicatmospheric velocities manifest themselves in broad line profiles.

Modeling of astronomically important atmosphericparameters, and the impact these parameters have on instrumentperformance, is a powerful tool for assessing the astronomicalpotential of Antarctic sites. This paper summarizes some of thesignificant findings from a combination of regional climate modelingand adaptive optics simulations. Together with estimates of the skybackground, this work strongly implies that the unique astronomicalpotential of Dome C – work that can be done at no other location – ishigh angular resolution science. In particular, the simulations showthat diffraction limited resolution in the optical is possible with amodest AO system deployed on a telescope mounted above the Antarcticboundary layer. This potential strongly differentiates Dome C fromother sites and suggests a tower-mounted, AO equipped, ~2.5 mclass telescope, located at Dome C, could be the premier visibleimaging observatory in the post-HST era.

We present preliminary results of the measurements of sky transparency conducted at Dome C during the winter 2008. Using MOLIERE modeling, we estimate a low precipitable water vapour content above Concordia station, which is very promising for future submillimetre wave observations on the Antarctic Plateau.

Chemodynamical disc galaxy simulations coupled with stellar populations synthesis models allow to build multi-wavelength images from numerical simulations, and then to follow their morphological evolution in colour and not only on the mass distribution. Using such technique, we present the evolution of several photometric observables, of the Tully-Fisher relation, as well as the evolution of disc structural parameters.

We provide insight into the origin of the far-IR to mm emission from the Galaxyby presenting a decomposition of the emission where we separate thecontributions from dust in the atomic gas and dust associated with quiescent molecular gas, as a function ofGalacto-centric distance. We find that the sub-mm dust emissivity per hydrogen change by afactor 3 between the diffuse ISM and molecular clouds, first observedon localized clouds in the Solar Neighborhood, applies on large scaleto the Molecular Ring. The decomposition leaves an emission excess inthe sub-mm with a very cold effective temperature, concentratedin the plane but with a brightness independent of Galacticlongitude. This emission might be associated with interstellar matterin the outer Galaxy not traced by H I nor CO emission.

In this paper, we consider the inverse problem of restoring an unknown signal or image, knowing the transformation suffered by the unknowns. More specifically we deal with transformations described by a linear model linking the unknown signal to an unnoisy version of the data. The measured data are generally corrupted by noise. This aspect of the problem is presented in the introduction for general models. In Section 2, we introduce the linear models, and some examples of linear inverse problems are presented. The specificities of the inverse problems are briefly mentionned and shown on a simple example. In Section 3, we give some information on classical distances or divergences. Indeed, an inverse problem is generally solved by minimizing a discrepancy function (divergence or distance) between the measured data and the model (here linear) of such data. Section 4 deals with the likelihood maximization and with their links with divergences minimization. The physical constraints on the solution are indicated and the Split Gradient Method (SGM) is detailed in Section 5. A constraint on the inferior bound of the solution is introduced at first; the positivity constraint is a particular case of such a constraint. We show how to obtain strictly, the multiplicative form of the algorithms. In a second step, the so-called flux constraint is introduced, and a complete algorithmic form is given. In Section 6 we give some brief information on acceleration method of such algorithms. A conclusion is given in Section 7.