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.

We have recently identified a previously unknown radial migration mechanism resulting from the overlap of spiral and bar resonances in galactic discs (Minchev & Famaey 2010; Minchev et al. 2010b). This new mechanism is much more efficient than mixing by transient spirals and its presence is unavoidable in all barred galaxies, such as our own Milky Way. The consequences of this are a strong flattening in the metallicity gradient in the disc, an extended disc profile, and the formation of a thick disc component, all taking place in only a couple of Gyr. This timescale is drastically shorter than previously expected and thus can put strong constraints on the longevity, strength and pattern speeds of the Galactic bar and Spiral Structure.

Recently, it has been suggested that the metallicity aversion of long-duration gamma-raybursts (LGRBs) is not intrinsic to their formation, but rather a consequence of theanti-correlation between star-formation and metallicity seen in the general galaxypopulation. To investigate this proposal, we compare the metallicity of the hosts ofLGRBs, broad-lined Type Ic (Ic-bl) supernovae (SNe), and Type II SNe to each other and tothe metallicity distribution of star-forming galaxies using the SDSS to represent galaxiesin the local universe and the TKRS for galaxies at intermediate redshifts. The differingmetallicity distributions of the LGRB hosts and the star-formation in local galaxiesforces us to conclude that the low-metallicity preference of LGRBs is not primarily drivenby the anti-correlation between star-formation and metallicity, but rather must beoverwhelmingly due to the astrophysics of the LGRBs themselves. Three quarters of our LGRBsample are found at metallicities below 12+log(O/H) < 8.6, whileless than a tenth of local star-formation is at similarly low metallicities. However, ourSN samples are statistically consistent with the metallicity distribution of the generalgalaxy population. Using the TKRS population of galaxies, we are able to exclude thepossibility that the LGRB host metallicity aversion is caused by the decrease in galaxymetallicity with redshift. The presence of the strong metallicity difference between LGRBsand Ic-bl SNe largely eliminates the possibility that the observed LGRB metallicity biasis a byproduct of a difference in the initial mass functions of the galaxy populations.Rather, metallicity below half-solar must be a fundamental component of the evolutionaryprocess that separates LGRBs from the vast majority of Ic-bl SNe and from the bulk oflocal star-formation.

In this course, I will review the main properties of internal gravity waves, andexamine how they can lead to particle and angular momentum transport in stars. Iwill then present some recent results that have been obtained for angularmomentum transport which show that waves are an important ingrediant of stellar modelling.

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.

We discuss the potential role that tidal flows in asynchronous binary stars may play in transporting chemically enriched material from deep layers towards the surface and the corresponding observational consequences of these processes. We suggest that the time-dependent velocity field induced by asynchronous rotation may contribute significantly to the mixing, thus providing a channel for the formation of chemically enriched slowly rotating massive stars.

Observations of spectroscopic double stars with long baseline optical interferometry have resolved many pairs, allowing their orbits to be measured and stellar masses and distances to be derived. A number of these measurements have accuracies worthy of comparison with high quality results from eclipsing binaries, thus able challenge stellar evolution models. I will review the contributions, and also show recent results, among them observations of massive O-stars and multiple systems.

Finite Difference and Finite Element algorithms for the solution of the radiative transfer equationas required for the modeling of modern high quality observations are briefly describedand discussed. It is emphasized that in the Finite Element approach there is the possibility to obtain an a-posteriori error estimator, which allows to locally refine the grid and in this way to obtain numerical solutions that do not differfrom the (unknown) analytical solutions by more than a prescribed tolerance.

"Densified-pupil multi-aperture imaging interferometers" also called "hypertelescopes" can provide direct images at their focal plane. Coronagraphic masking is applicable for nulling a star's image and searching associated planets. The scheme is applicable at the infra-red wavelengths where a planet has its best contrast, but also potentially at visible wavelengths where chlorophyll-like spectral features are to be searched. In the infra-red, where zodiacal and exo-zodiacal clouds tend to contaminate the image, the scheme provides a better rejection of this contamination than schemes using a beam-splitter and flat interference. For a typical Earth-like exo-planet the detection time is reduced 10 to 100 times. In the visible, planets are often resolved from their star by an interferometer's sub-aperture. Visible coronagraphy is then achievable in each sub-aperture before combining the beams and producing the high-resolution image. This relaxes the piston tolerances. Whether for sub-apertures or a densified pupil, or even a conventional telescope, multiple stages ofcoronagraphy are of interest, if equipped with as many deformable mirrors or transmissive plates. Located in the successive image planes, such adaptive correctors can phase the residual stellar speckles without affecting the planet peak. This generates a central peak of starlight, which can be masked without much obstructing the planet's wavefront. A design concept studied for an "Exo-Earth Discoverer", a hypertelescope variant proposed to NASA for its Terrestrial Planet Finder, involves 37 mirror elements of 1 m, driven by small solar sails and arranged to form a 40-300 m diluted spherical mirror. One or several focal combiners move along the focal surface. Optical solutions have been explored in preliminary detail.

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.

Non-LTE modelling for a particular atom requires accurate collisional excitation and ionization cross-sections for the entire system of transitions in the atom. This review concerns with inelastic collisions with electrons and neutral hydrogen atoms. For the selected atoms, H i and Ca ii, comparisons are made between electron impact excitation rates from ab initio calculations and various theoretical approximations. The effect of the use of modern data on non-LTE modelling is shown. For most transitions and most atoms, hydrogen collisional rates are calculated using a semi-empirical modification of the classical Thomson formula for ionization by electrons. Approaches used to estimate empirically the efficiency of hydrogenic collisions in the statistical equilibrium of atoms are reviewed.

Due to severe time constraints, the joint discussion for sessions I-IV has be beenextremely short considering the number of hot topics related to GRB prompt emissionstudies and the physics of GRB ultra-relativistic outflows. I attempt to briefly describethe main issues raised in the talks and posters presented during the conference.

Laboratory measurements aimed at studying the properties of carbonaceous materials and their evolution under simulated space conditions support the idea that interstellar carbon dust evolves through exposure to UV and cosmic rays, gas and heat. After summarizing the principal aspects of the laboratory approach to the problem of cosmic carbon dust, we discuss recent laboratory results showing how carbon grains influence the properties and evolution of ices mantles and the formation of molecular hydrogen.

Substructure in ΛCDM provides a number of interesting puzzles. While the missing satellites problem is well-studied, there are suggestions of an opposite problem on the bright end. Subhalos large enough to host luminous satellites are uncommon, so the existence of the Large Magellanic Cloud (LMC) orbiting the Galaxy can potentially be a challenge for ΛCDM. Hence, we describe a search for analogs to an isolated galaxy pair like the Milky Way/LMC system in the SDSS and interpret these results with cosmological simulations. We note that while the LMC may not be unusual based on its luminosity, it is remarkably blue for such satellites. Thus, color may have implications for the LMC’s orbital history.


We describe in this communication the principle of imaging withdiluted apertures from the theoretical point of view of Fourieroptics, for a noiseless experiment using perfect telescopes inspace. Two extreme cases are considered, corresponding to denseand sparse arrays. Dense arrays make it possible to obtain acomplete spatial frequency coverage; after signal processing, theimages are comparable to those obtained with a very largemonolithic aperture. Such a perfect frequency coverage cannot beobtained with parse arrays for which the distances betweentelescopes are very large compared to their size. These arrays canonly sample the Fourier plane at point-like individualfrequencies, with the drawback of a field limitation. Sparsearrays have however the most promising perspectives for imagery ofstars and exoplanets surfaces.

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.

This chapter is primarily intended as an introductory text, a pedagogical platform, on the phenomenon ofturbulence in fluids. For the sake of simplicity, the discussion is mostly limited to the case of anincompressible (constant-property) newtonian fluid in simple three-dimensional turbulent flows. Additionalcomplexities related to thermal convection, magnetic forces, nuclear reactions and so forth are ignored onpurpose.The main motivation is to exhibit the general problematic of turbulence in an as simple as possible physicalsetting. Modelling prospecting, which aims at elaborating numerically tractable mathematical models of turbulence,is also brought up.


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.

The MIMAC project is based on a matrix of Micro Time Projection Chambers (μ-TPC) for Dark Matter search, filled with He3 or CF4 and using ionization and tracks. The first measurement of the energy resolution of this μ-TPC is presented as well as its low threshold.

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.