Infrared focal plane technology has evolved rapidly in the past two decades. The detector format has grown from single pixel detectors to 4K × 4K pixel arrays, and a mosaic of 4 × 4 2K × 2K pixel arrays and six mosaics of 2 × 2 2K × 2K pixel arrays are already in operation at ground based telescopes. The quantum efficiency of these arrays is close to 100%, the readout noise a few electrons rms and the dark current a few electrons per hour. However, the latent image problem has not been solved yet. A persistence model and a mitigation strategy will be discussed briefly. Specialized ASIC readout chips which digitize the multichannel video signals of large arrays directly on the focal plane are becoming available for large format arrays and they will eventually replace conventional controllers. In the mid infrared a high flux version of the MIRI detector is being developed for ground based applications. Fast low noise infrared sensors are needed for wavefront sensors of adaptive optics (AO) systems. To meet both the speed and the noise requirements two different technical approaches are being followed. One solution is the use of high gain CTIA amplifiers in the detector unit cell, the other solution is to exploit the noiseless gain mechanism of HgCdTe electron avalanche photodiode (eAPD) arrays.

Laboratory experiments demonstrate that current sheets evolving in magnetized plasmas can give rise to both flare-type events and generation of energetic plasma jets.

Stellar models including atomic diffusion processes (gravitational settling, radiative accelerations, thermal diffusion, in addition to the purely diffusive term) have now been evolved throughout most of stellar evolution. We review some of the major roles of diffusion processes in stellar evolution. The emphasis is on interior properties. Examples include Populations I and II stars. It is emphasized that competing advective processes such as mass loss or meridional circulation modify internal concentrations differently from turbulent diffusion even when they lead to the same surface abundances. Radiative accelerations play a major role in horizontal branch and sdB stars.

We present interpretations of the line-of-sight velocity distribution of stars in theDraco dwarf spheroidal galaxy in terms of CDM and MOND assuming constant mass-to-light ratioand anisotropy. We estimate the two parameters by fittingthe line-of-sight velocity dispersion and kurtosis profiles for stellar samplesdiffering by a number of stars rejected as interlopers.The results of the fitting procedure for CDM, high mass-to-light ratio(131–141 solar units in the V-band) and weakly tangential orbits, are similar fordifferent samples, but the quality of the fit is much worse when fewer interlopersare removed. For MOND, the derived mass-to-light ratio (21 solar units) is too large to beexplained by the stellar content of the galaxy.

The GALAH survey targets one million stars in the southern hemisphere down to a limiting magnitude of V = 14 at the Anglo-Australian Telescope. The project aims to measure up to 30 elemental abundances and radial velocities (≈1 km s−1 accuracy) for each star at a resolution of R = 28,000. These elements fall into 8 independent groups (e.g.α, Fe peak, r-process). For all stars, Gaia will provide distances to 1% and transverse velocities to 1 km s−1 or better, giving us a 14D set of parameters for each star, i.e. 6D phase space and 8D abundance space. There are many scientific applications but here we focus on the prospect of chemically tagging the thick disk and making a direct measurement of how stellar migration evolves with cosmic time.

Theoretical atmosphere models provide the basis for a variety of applications in astronomy. In simplified one-dimensional (1D) atmosphere models, convection is usually treated with the mixing length theory despite its well-known insufficiency, therefore, the superadiabatic regime is poorly rendered. Due to the increasing computational power over the last decades, we are now capable to compute large grids of realistic three-dimensional (3D) hydrodynamical model atmospheres with the realistic treatment of the radiative transfer. We have computed the Stagger-grid, a comprehensive grid of 3D atmosphere models for late-type stars. In the presented contribution, we discuss initial results of the grid by exploring global properties and mean stratifications of the 3D models. Furthermore, we also depict the differences to classic 1D atmosphere models.

The MIMAC project aims to provide a nominal fluorine detector for directional detection of galactic dark matter recoil events. Its expected behavior reaches an important part of the predicted spin dependent elastic scattering interactions of the supersymmetric neutralino with protons. Hence, the parameter space in the MSSM and the NMSSM models with neutralino dark matter could be probed by such experimental efforts. In particular, a good sensitivity to spin dependent interactions tackles parameter space regions to which the predictions on spin independent interactions and indirect signatures are far below current and projected experiments.

Polycyclic Aromatic Hydrocarbons (PAHs) are widespread across the Universe and influencemany stages of the Galactic lifecycle. The presence of PAHs has been well established andthe rich mid-IR PAH spectrum is now commonly used as a probe into (inter)stellarenvironments. The NASA Ames PAH IR Spectroscopic Database has been key to test and refinethe “PAH hypothesis”. This database is a large coherent set (>600 spectra) oflaboratory measured and DFT computed infrared spectra of PAHs fromC10H8 to C130H28 and has been made availableon the web at (http://www.astrochem.org/pahdb). With a new spectral window opening up; thefar-IR, the study of PAH far-IR spectra and the quest for identifying aunique member of the interstellar PAH family has begun. To guide this research, the far-IR(>20 μm) spectra of different sets of PAHs are investigatedusing the NASA Ames PAH IR Spectroscopic Database. These sets explore the influence ofsize, shape, charge and composition on the far-IR PAH spectrum. The far-IR is also thedomain of the so-called “drumhead” modes and other molecular vibrations involving loworder bending vibrations of the carbon skeleton as a whole. As with drums, these aremolecule and shape specific and promise to be a key diagnostic for specific PAHs. Here,the sensitivity of these “drumhead” modes to size and shape is assessed by comparing thefrequencies of the lowest drumhead modes of a family of circular shaped (the coronene“family”) and rhombus shaped (the pyrene “family”) PAH molecules. From this study, someconsequences for an observing strategy are drawn.

Young galaxies are clumpy, gas-rich, and highly turbulent. Star formation appears to occur by gravitational instabilities in galactic disks. The high dispersion makes the clumps massive and the disks thick. The star formation rate should be comparable to the gas accretion rate of the whole galaxy, because star formation is usually rapid and the gas would be depleted quickly otherwise. The empirical laws for star formation found locally hold at redshifts around 2, although the molecular gas consumption time appears to be smaller, and mergers appear to form stars with a slightly higher efficiency than the majority of disk galaxies.

The inclusion of rotation in massive star models improves the agreement between theory and observations in many respects that are briefly recalled here. Rotational mixing, by changing the chemical profiles in the stellar interiors, has important impacts on nucleosynthesis.We shall first discuss the case of solar metallicity models and then explore consequencesboth in the high and very low metallicity ranges. The effects in very metal–poor stars arespectacular and give new insights on the evolution of the early star generations in the Universe.

The ARENA Solar Astrophysics Working Group (WG6) is reviewing the exceptional site conditions prevailing at Dome C/Concordia making it a unique place on Earth for solar observations: excellent seeing, low sky brightness, low water vapour and high duty cycle. These qualities open science programmes which can combine very high resolution, coronagraphy, infrared access, and long time series (continuity). Major objectives accessible are the chromosphere-corona interface at very high resolution, direct magnetic field measurements in the chromosphere (prominences) and in the corona, 2D imaging spectroscopy and waves. A first mid-size facility is proposed and described, AFSIIC (Antarctica Facility for Solar Interferometric Imaging and Coronagraphy), using 3×Ø50 cm off-axis telescopes (1.4 m equivalent telescope) to access these objectives with the proper flux, angular resolution and coronagraphic potential. Support infrastructure and logistics have been studied and are discussed, noticeably a 30 m tower to place the observatory over the very thin surface turbulent layer of Dome C.

We use cosmological hydrodynamic simulations with enriched galacticoutflows to compare predictions for the galaxy mass-metallicity (M* − Z)with observations at z ≈ 2 from Erb et al. (2006). With no outflowsincluded galaxies are over-enriched, indicating that outflows are requirednot only to suppress star formation and enrich the IGM but also to lowergalaxy metal content. The observed M* − Z slope is matched both inour model without winds as well as in our favored outflow model where theoutflow velocity scales as the escape velocity, but is too steep ina model with constant outflow speeds. If outflows are too widespreadat early times, the IGM out of which smaller galaxies form can becomepre-polluted, resulting in a low-mass flattening of the M* − Z relationthat is inconsistent with data. Remarkably, the same momentum-drivenwind model that provides the best agreement with IGM enrichment dataalso yields the best agreement with the z ≈ 2 M* − Z relation,showing the proper outflow scaling and strength to match the observedslope and amplitude. In this model, the M* − Z relation evolves slowlyfrom z = 6 → 2; an (admittedly uncertain) extrapolation to z = 0broadly matches local M* − Z observations. Overall, the M* − Zrelation provides critical constraints on galactic outflow processesduring the heyday of star formation in the Universe.

X-ray solar coronal jets are short–duration, fast, well collimated plasma brightenings occurring in the solar corona. To explain and understand the processes driving the jets, one must be able to model an explosive release of free energy. Magnetic reconnection is believed to play a key role in the generation of these energetic bursting events. The model of jets that we have been developing is based on a magnetic field constructed by embedding a vertical magnetic dipole in a uniform open magnetic field. In this study, we investigate the influence of the inclination of the open field on the properties of the jet using numerical simulations. We will show that the inclination of the open field is of critical importance for the properties of the jet such as the energy released. We conclude that the characteristics of the open field at the time of observations are a central criterion that must be taken into account and reported on in observational studies.

Very High Dynamics Imaging rounds up various techniques that can be used to study the close environmentof a source which flux, comparatively very large, prevents to see the morphological featuresimmediately neighbouring the source.Several instrumental approaches have been devised in this purpose, among which apodisation, mask coronagraphy and nulling techniques. In view of applying them to various scientific programs, both shared constraints andspecific features of the approaches have to be identified. This is the subject of this paper,which also recalls basics principles. A new concept (EvWaCo) achieving coronagraphy by usingevanescent waves is briefly outlined.

The ESA Cornerstone Mission GAIA, to be launched prior to 2012 and witha nominal lifetime of 5 years, will improve the accuracy of Hipparcosastrometry by more than two orders of magnitude.GAIA high-precision global astrometric measurements will provide deep insightson the science of extra-solar planets. The GAIA contribution is primarilyunderstood in terms of the number and spectral type of targets availablefor investigation, and characteristics of the planets to be searched for.Several hundreds of thousands of solar-type stars (F-G-K) within a sphereof ~200 pc centered on our Sun will be observed. GAIA will be particularlysensitive to giant planets (MP ~ MJ)on wide orbits, up to periods twice as large as the mission duration, thepotential signposts of the existence of rocky planets in the Habitable Zone.Thousands of new planets might be discovered, and a significant fractionof those which will be detected will have orbital parameters measured tobetter than 30% accuracy. By measuring to a few degreesthe relative inclinations of planets in multiple systems with favorableconfigurations, GAIA will also make measurements of unique value towards abetter understanding of the formation and evolution processes of planetarysystems.

Classical Cepheid stars have been considered since more than a century as reliable tools to estimate distances in the universe thanks to their Period-Luminosity (P-L) relationship. Moreover, they are also powerful astrophysical laboratories, providing fundamental clues for studying the pulsation and evolution of intermediate-mass stars. When in binary systems, we can investigate the age and evolution of the Cepheid, estimate the mass and distance, and constrain theoretical models. However, most of the companions are located too close to the Cepheid (∼1–40 mas) to be spatially resolved with a 10-meter class telescope. The only way to spatially resolve such systems is to use long-baseline interferometry. Recently, we have started a unique and long-term interferometric program that aims at detecting and characterizing physical parameters of the Cepheid companions, with as main objectives the determination of accurate masses and geometric distances.

In this communication we study the statistics of Adaptive Optics remnant speckles, and we discuss how a coronagraph can defeat the noise associated with these speckles. At high Strehl Ratio regimes, residual speckles are pinned on the diffraction rings of the airy pattern. It can be shown that these speckles are due to small defaults of the wavefront, amplified by the coherent part of the wave and that the statistics of their intensity can be described by a modified Rice distribution. At low flux levels, a Poisson-Mandel transformation provides an analytical expression of the Probablility Density Function. We show the results of a numerical simulation and compare the results to the theoretical model. Simple analytical expressions can be derived for the variance of the noise.We discuss the efficiency of a coronagraph in terms of Signal to Noise Ratio, based on the analysis of the noise contributions which can be reduced by a coronagraph.

The Phoenix dwarf galaxy is the nearest and most typical representative of the class of the so-called transition dwarf galaxies (from spheroidal to irregular). We present here precise velocity measurements obtained from high-resolution spectroscopy of more than one hundred member stars, allowing us to study the stellar kinematics and estimate the internal velocity dispersion and dark matter content.

Fossil magnetic fields (i.e. fields that survive from one stage ofstellar evolution to a significantly later epoch withoutbeing regenerated) have been invoked to explain phenomena in the Sun, magnetic CP stars, white dwarfsand neutron stars. The feasibility of such processes is discussed critically. Estimates are made that suggest that flux survivalthrough pre-main sequence evolution is more likely to occur in stars withM > 1 M⊙. Any link between CP star and white dwarf magnetism is argued to favour the fossil field origin of CP star fields.

The observational constraints on interstellar dust are summarized. A dust model, consisting of a mixture of amorphous silicate, graphite, and PAH material that reproduces the observed interstellar extinction, is described. It is used to calculate the infrared emission expected when such dust is heated by radiation with the spectrum of interstellar starlight with various intensities. By adopting a suitable size distribution for the smallest carbonaceous grains (PAHs), and a distribution of starlight intensities, one can reproduce the observed global emission spectrum of galaxies. This allows the total dust mass, and the PAH abundance, to be estimated for any galaxy with a spectral energy distribution measured by the IRAC and MIPS cameras on Spitzer Space Telescope. For the Spitzer Infrared Nearby Galaxies Survey (SINGS) sample, galaxies with metallicities Z > 0.3 Z๏ tend to have a major fraction of their refractory elements in dust grains, just as in the Milky Way. For lower metallicity galaxies with extended H I envelopes, the overall dust-to-metals ratio remains uncertain. The PAH abundance index qPAH (the fraction of the total dust mass in PAH particles with NC < 103 C atoms) is dependent on metallicity: galaxies with Z <0.3 Z๏ have median qPAH = 1.1%, whereas galaxies with Z > 0.3 Z๏ have median qPAH = 3.5%. The reasons for the pronounced dependence of qPAH on metallicity remain unclear.