For many years, our group has been investigating the VUV spectroscopy and photochemistry of molecules of astrophysical (Jochims et al. 2006a,b; Leach et al. 2008; Schwell et al. 2012) and prebiotic interest (Schwell et al. 2006). Polyynes and cyano-polyynes that are abundant in the interstellar medium (ISM) and in planetary atmospheres, have been investigated too (e.g. Fray et al. 2010). An aerosol source for reactive and thermo-labile compounds has been developed (Gaie-Levrel et al. 2011) to perform gas-phase measurements. These are necessary to measure intrinsic molecular properties and to compare to quantum chemical calculations. Besides measuring absolute absorption and photoionization cross sections, dissociative channels and their involved excited states are identified for a number of molecules of interstellar interest. Branching ratios of the respective elementary photoreactions are determined in order to understand and model the photochemistry occurring in the ISM. Some very recent results on the dissociative photoionization of methylformate (MF), glycolaldehyde (GA), dimethylether (DIM), aminoacetonitrile (AAC) and cyanoacetylene (CA), are presented here.

The processing of dust in shocks in the interstellar medium can lead to changes in the dust to gas mass ratio and also to a radical evolution of the dust size distribution. Here we focus on the important results of numerical models that simulate the impact of shocks on the interstellar dust size distribution in molecular clouds and in the warm intercloud medium. We emphasize the necessity of detailed modelling of the grain charging processes and the grain inertia in order to unravel the complexities and consequences of the dust dynamics in shock waves.

A review of the observational constraints and theoretical models of extra-planar rotation (lagging halos) is presented. It is becoming clear that lagging halos, with vertical gradients in rotation speeds ranging from dvΘ/dz = −8to − 60km s−1kpc−1, are a ubiquitous phenomenon. The observational data so far does not allow one to say definitively whether this number changes with radius or with vertical height in a galaxy, but it is pointed out that such measurements, along with constraints on the presence of radial flows, will provide a crucial test that may allow one to distinguish between the different physical models that produce lagging halos. Some challenges in kinematically distinguishing between Galactic circulation and extragalactic accretion are also discussed.

In a first part of the paper we give a simple introduction to the free space propagation of light at the level of a Master degree in Physics. The presentation promotes linear filtering aspects at the expense of fundamental physics. Following the Huygens-Fresnel approach, the propagation of the wave writes as a convolution relationship, the impulse response being a quadratic phase factor. We give the corresponding filter in the Fourier plane. As an illustration, we describe the propagation of wave with a spatial sinusoidal amplitude, introduce lenses as quadratic phase transmissions, discuss their Fourier transform properties and give some properties of Soret screens. Classical diffractions of rectangular diaphragms are also given here. In a second part of the paper, the presentation turns into the use of external occulters in coronagraphy for the detection of exoplanets and the study of the solar corona. Making use of Lommel series expansions, we obtain the analytical expression for the diffraction of a circular opaque screen, giving thereby the complete formalism for the Arago-Poisson spot. We include there shaped occulters. The paper ends up with a brief application to incoherent imaging in astronomy.

The influence of a magnetic field on the broadening of spectral lines and transition arrays in complex spectra is investigated. The anomalous absorption or emission Zeeman pattern is a superposition of many profiles with different relative strengths, shifts, widths, asymmetries and sharpnesses. The σ and π profiles can be described statistically, using the moments of the Zeeman components. We present two statistical modellings: the first one provides a diagnostic of the magnetic field and the second one can be used to include the effect of a magnetic field on simulated atomic spectra in an approximate way.

Near-infrared (NIR; 2.5–5 μm) low-resolution(λ/Δλ ~ 100) spectra were obtained for anumber of Galactic and extragalactic objects with the Infrared Camera (IRC) in the AKARIwarm mission. These data provide us with the first opportunity to make a systematic studyof the 3.3–3.5 μm PAH features in a galactic scale as well as within anobject. Whereas the 3.3 μm band is well resolved in most spectra, the3.5 μm band is not clearly separated from the 3.4 μmband in the IRC spectrum. The intensity ratio of the summation of the 3.4 and3.5 μm bands to the 3.3 μm band shows a tendency toincrease towards the Galactic center, although a large variation in the ratio is also seenin a local scale. A search for deuterated PAH features in the 4 μm regionis carried out in IRC NIR spectra. Emission lines originating from the ionized gastogether with the detector anomaly hamper an accurate search at certain wavelengths, butlittle convincing evidence has so far been obtained for the presence of significantfeatures in 4.2–4.7 μm. A conservative upper limit of a few percents isobtained for the integrated intensity ratio of the 4.4–4.7 μm possiblefeatures to the 3.3–3.5 μm PAH features in the spectra so farobtained.

Recent systematic surveys providing massive datasets of white dwarf stars show that there is still a deficit of a factor of 2.5 in the ratio of white dwarfs showing helium absorption lines to those with hydrogen absorption lines in the temperature range 30 000 K < Teff < 45 000 K. Since all white dwarfs have to evolve through this temperature range along similar sequences in the color-magnitude diagram, this implies that most of the helium atmosphere white dwarfs evolve into hydrogen atmosphere hot DA stars in that temperature range and then back again to helium atmosphere white dwarfs. I describe possible scenarios for this chameleon-like disguises of white dwarfs with helium dominant atmospheres and a new kind of pulsating white dwarfs predicted to appear near the lower end of the temperature range 45 000–30 000 K from these scenarios. Recently searches have discovered a pulsating DA white dwarf, WD1017−138, in the predicted temperature range. This discovery opens the possibility of a direct test of the explanation for the deficit of helium atmosphere white dwarfs at these temperatures by asteroseismic probing of the atmospheric layers of the hot DAV stars.

Gamma-ray bursts (GRB) are extremely energetic events and produce highly diverse lightcurves. Light curves are believed to be resulting from internal shocks reflecting theactivities of the GRB central engine. Hence their temporal studies can potentially lead tothe understanding of the GRB central engine and its evolution. The light curve variabilitytime scale is an interesting parameter which most models attribute to a physical origine.g., central engine activity, clumpy circum-burst medium, orrelativistic turbulence. We develop a statistical method to estimate the GRB minimumvariability time scale (MVT) for long and short GRBs detected by GBM. We find that the MVTof short bursts is distinctly shorter than that for long GRBs supporting the possibilityof a more compact central engine of the former. We find that MVT estimated by this methodis consistent with the shortest rise time of the fitted pulses. Hence we use the fittedpulse rise times to study the evolution of burst variability time scale. Variability timeis in turn related to the minimum bulk Lorentz factor. Using this we relate the GRBspectral evolution to the evolution of the variability time scale.


We report our recent progress on extragalactic spectroscopic and continuum observations,including HCN(J=1–0), HCO+(J=1–0), and CN(N=1–0) imaging surveys of local Seyfert and starburst galaxies using the Nobeyama Millimeter Array,high-J CO observations (J=3–2 observations using the Atacama Submillimeter Telescope Experiment (ASTE) and J=2–1 observations with the Submillimeter Array) of galaxies, and λ 1.1 mm continuum observations of high-z violent starburst galaxiesusing the bolometer camera AzTEC mounted on ASTE.

The OASI group have been active in Antarctica since 1986: from the pioneering period,though the 2.62 m mm telescope activity at Terra Nova Bay to the first observing campaigns atDome C.The group activity significantely contributed to the development of mm Italian Antarcticastronomy, acting as a pathfinder for present success and future development. The overallitalian activity is characterised by interesting scientific results, obtained even when adequatefunding was not available.The historical evolution of the italian mm activities in Antarctica will be illustrated and theperspective for future experiments will be reported.

We present the results of the analysis of our recent interferometric observations of Betelgeuse, using the AMBER instrument of the VLTI. Using the medium spectral resolution mode (R ~ 1500) we detected the presence of the water vapour and carbon monoxide (CO) molecules in the H and K bands. We also derived the photospheric angular diameter in the continuum. By analysing the depth of the molecular lines and the interferometric visibilities, we derived the column densities of the molecules, as well as the temperature and the size of the corresponding regions in the atmosphere of Betelgeuse (the MOLsphere) using a single shell model around the photosphere. Our results confirm the findings by Perrin et al. (2004) and Ohnaka et al. (2011) that the H2O and CO molecules are distributed around Betelgeuse in a MOLsphere extending to approximately 1.3 times the star’s photospheric radius.

As a by-product of β Cephei and δ Cephei radiative model surveys we have found interesting cases of multimode pulsation. In case of β Cephei stars, we found two multimode domains with two or three modes being involved. The origin of the multimode pulsation can be traced to one of the two different mechanisms: either to the non-resonant coupling of the two excited modes (double-mode pulsation) or to the 2ω1$\simeq$ω0 + ω2 parametric resonance (triple-mode pulsation). In case of δ Cephei models, a triple-mode pulsation domain, connected with the 2:1 resonance, 2ω0$\simeq$ω2, is found. These models are of theoretical interest only, since they do not obey a proper mass-luminosity relation.

We present a new 3D continuum radiative transfer code, MCFOST, based on a Monte-Carlo method. The reliability and efficiencyof the code is tested by comparison with five different radiative transfer codespreviously tested by Pascucci et al. (2004), using a 2D diskconfiguration. When tested against the same disk configuration,no significant difference is found between the temperature and SEDcalculated with MCFOST and with the other codes. Thecomputed values are well within the range of values computed by theother codes. The code-to-code differences are small, they rarelyexceed 10% and are usually much smaller.

Directional detection is a promising search strategy to discover galactic Dark Matter. We present a Bayesian analysis framework dedicated to data from upcoming directional detectors. The interest of directional detection as a powerful tool to set exclusion limits, to authentify a Dark Matter detection or to constrain the Dark Matter properties, both from particle physics and galactic halo physics, will be demonstrated.

The serendipitous discovery of a gravitational lens system formedby an elliptical galaxy at z ~ 1 and a post-starburstgalaxy at z ~ 3.8 brings a unique opportunity to study indetail the mass profile of a massive and relaxed object at a lookback time of half the age of the universe. We sketch here a comparisonof different methods to reconstruct the mass of the lens, both parametricallyand non-parametrically, highlighting their advantanges and limitations.

The standard model of cosmology considers the existence of two components of unknown nature, “dark matter” and “dark energy”, which determine the cosmological evolution. Their nature remains unknown, and other models can also be considered. In particular, it may be possible to reinterpret the recent cosmological observations so that the Universe does not contain two fluids of unknown natures, but only one fluid with particular properties. After a brief review of constraints on this unifying “dark fluid”, we will discuss a specific model of dark fluid based on a complex scalar fluid.

Chondritic meteorites constitute the most ancient rock record available in the laboratory to study the formation of the solar system and its planets. Detailed investigations of their mineralogy, petrography, chemistry and isotopic composition and comparison with other primitive solar system samples such as cometary dust particles have allowed through the years to decipher the conditions of formation of their individual components thought to have once been free-floating pieces of dust and rocks in the early solar nebula. When put in the context of astrophysical models of young stellar objects, chondritic meteorites and cometary dust bring essential insights on the astrophysical conditions prevailing in the very first stages of the solar system. Several exemples are shown in this chapter, which include (1) high temperature processes and the formation of chondrules and refractory inclusions, (2) oxygen isotopes and their bearing on photochemistry and large scale geochemical reservoirs in the nebula, (3) organosynthesis and cold cloud chemistry recorded by organic matter and hydrogen isotopes, (4) irradiation of solids by flares from the young Sun and finally (5) large scale transport and mixing of material evidenced in chondritic interplanetary dust particles and samples returned from comet Wild2 by the Stardust mission.

The status of the AMICA project is reported. Final tests are currently running at Teramo Observatory before moving the instrument to Antarctica. AMICA is a camera equipped with two array detectors to perform astronomical imaging in the 2–28 μm band. It will be mounted at the IRAIT focal plane. Its very special feature is the antarctic operability. AMICA subsystems have been tested at typical antarctic conditions, in order to adopt technological solutions that ensure the correct operation of AMICA even on the antarctic plateau. Moreover, since human operations are not possible during the antarctic “winter", AMICA has been designed to operate in a completely automatic mode. AMICA is essentially aimed to demonstrate the potential of Antarctica for Infrared Astronomy and should therefore produce significant data, both for astronomy and site-testing. In addition, the experience gained in its technological development will be useful for building future astronomical instruments for extreme environment sites.


Using hydrodynamical cosmological simulations we investigate the effect of baryonic dissipation on halo shapes. We show that dissipational simulations produce significantly rounder halos than those formed in equivalent dissipationless simulations. Gas cooling causes an average increase in halo principal axis ratios of ~0.2−0.4 in the inner regions and a systematic shift that persists out to the virial radius, alleviating any tension between theory and observations. Although the magnitude of the effect may be overestimated due to overcooling, cluster formation simulations designed to reproduce the observed fraction of cold baryons still produce substantially rounder halos. Subhalos also exhibit a trend of increased axis ratios in dissipational simulations. Moreover, we demonstrate that subhalos are generally rounder than corresponding field halos even in dissipationless simulations. All of these results highlight the vital role of baryonic processes in comparing theory with observations and warn against over-interpreting discrepancies with collisionless simulations on small scales.