This paper presents an ultra low noise instrumentation based on cryogenic electronic integrated circuit. We have designed an ASIC (Application Specific Integrated Circuit) in standard BiCMOS SiGe 0.35 μm AMS technology. The main functions of this circuit, the readout and the control of a 24 to 1 SQUID multiplexer, is presented. We also report the cryogenic operation of each part of this ASIC.

In the current cosmological scenario, part of the linearly polarizedemission of the CMB is expected to be rotational (B-modes). Thiscomponent is due to tensor perturbations of the metric produced byprimordial gravitational waves, which are generated a split-second after theBig Bang. The signal expected is of the order of ≲ 0.1 μK, well below the non-rotational component of the polarizationsignal (E-modes), and beyond the sensitivity of present generationinstruments. New, more sensitive instruments are developed inseveral labs, with the goal to measure the B-modes. Control ofsystematics and foregrounds will be the key to make the results ofthese experiments believable. In this paper we shortly outlineBRAIN, a bolometric interferometer devoted to B-modes research,and its pathfinder experiment, devoted to test the Dome-C site.



The solar interior has been scrutinized by two different and independent probes during the last twenty years with important revisions of the solar model, including a recent heavy element abundancerevision. Today, we get a quantitatively coherent picture (even incomplete) of the solar (stellar) radiative zones. In this review, we recallthe clues for solar gravitational settling definitively established by the seismic determination of the photospheric helium content. We comment also on the need for mixing in the transition region between radiation and convectionin the case of the Sun and of population II stars. We finally list the open questions and the importance to continue more precise investigations of the solar (stellar) radiative zone in detecting gravity modes with the project DynaMICS.

This article first provides a historical and detailed introduction to the image formation models for diluted pupils array and their densified versions called hypertelescopes. We propose in particular an original derivation showing that densification using a periscopic setting like in Michelson’s 20 −  foot interferometer, or using inverted Galilean telescopes are fully equivalent. After a review based on previous reference studies (Tallon & Tallon-Bosc 1992; Labeyrie 1996; Aime 2008 and Aime et al. 2012), the introductory part ends with a tutorial section for simulating optical interferometric images produced by cophased arrays. We illustrate in details how the optical image formation model can be used to simulate hypertelescopes images, including sampling issues and their effects on the observed images.

In a second part of the article, we address the issue of restoring hypertelescope images and present numerical illustrations obtained for classical (constrained Maximum Likelihood) methods. We also provide a detailed survey of more recent deconvolution methods based on sparse representations and of their spread in interferometric image reconstruction.

The last part of the article is dedicated to two original and numerical studies. The first study shows by Monte Carlo simulations that the restoration quality achieved by constrained ML methods applied to photon limited images obtained from a diluted array on a square grid, or from a densified array (without spectral aliasing) on a grid, are essentially equivalent. The second study shows that it is possible to recover in hypertelescopes images quasi point sources that are not only far outside the clean field, but also superimposed on the replicas of other objects. This is true at least for the considered pupil array and in the limit of vanishing noise.

Much progress has recently been made in understanding and quantifying vertical mixing induced by double-diffusive instabilities such as fingering convection (usually called thermohaline convection) and oscillatory double-diffusive convection (a process closely related to semiconvection). This was prompted in parts by advances in supercomputing, which allow us to run Direct Numerical Simulations of these processes at parameter values approaching those relevant in stellar interiors, and in parts by recent theoretical developments in oceanography where such instabilities also occur. In this paper I summarize these recent findings, and propose new mixing parametrizations for both processes that can easily be implemented in stellar evolution codes.

ESPaDOnS is a new-generation cross-dispersed échelle spectropolarimeter, the commissioning phase of which is scheduled at the Canada-France-Hawaii Telescope (CFHT) for autumn 2003. This instrument will provide full coverage of the optical domain (370 nm to 1000 nm) in all polarization states (circular and linear) at a resolving power of about 70 000, with a peak efficiency of 20% (telescope and detector included). It includes a bench-mounted spectrograph, fiber-fed from a Cassegrain-mounted module including all polarimetric and calibration facilities. ESPaDOnS should be the most powerful tool dedicated to stellar spectropolarimetry, therefore opening unprecedented perspectives for major issues of stellar physics, from studies of stellar interiors to investigations of stellar atmospheres, stellar surfaces, stellar magnetic fields, and to observations of circumstellar environments and extra-solar planets.

The ESA Gaia mission will provide a multi-epoch database for a billion of objects,including variable objects that comprise stars, active galactic nuclei and asteroids. Wehighlight a few of Gaia’s properties that will benefit the study of variable objects, andillustrate with two examples the work being done in the preparation of the data processingand object characterization. The first example relates to the analysis of the nearlysimultaneous multi-band data of Gaia with the Principal Component Analysis techniques, andthe second example concerns the classification of Gaia time series into variability types.The results of the ground-based processing of Gaia’s variable objects data will be madeavailable to the scientific community through the intermediate and final ESA releasesthroughout the mission.

Dust forming systems, in which a phase transition between the gas phase and the solid state takes place, are seriously affected by the presence of dust, which causes tight, non-linear interactions between various physical and chemical processes. As a consequence, the dynamics of, e.g., a stellar atmosphere and the formation ofdust grains are inseparably connected. Chemical conditions, dust formation, and dust-induced instabilities in such non-linearly coupled systems as well as some implications regarding stellar evolution are discussed.

We present the initial performance of the Gaia Radial Velocity Spectrometer, providing an overview of its performance, which is essentially nominal in terms of spectral resolution, throughput and operation, except for the presence of unexpectedly high levels of scattered background. This is mainly Solar in origin, and reduces the limiting magnitude for radial velocity measurements by ∼1 magnitude to V  ∼ 16. Radial velocity calibration accuracies are compliant with requirements.

The CEA, in coordination with IPEV and LUAN, will prepare an experiment to study frost formation on surfaces in radiative cooling in the winter. This experiment has been shipped to be installed at Concordia before the 2007 winter period. It will be controlled from Concordia winterover personal, through PC server that will locally archive data from WEBcams and several local heat regulators. This experiment will be used to give recipes on the way to compensate with heaters the radiative cooling from the sky and maintain instrument surfaces at temperature just above icing conditions. The individual regulators proposed in this experiment will be usable as standalone ice protection systems for existing and future telescopes.

We have used the CFHT and Gemini South telescopes to obtain high-resolution, high signal-to-noise optical and near-infrared spectra of several lines of neutral helium in a number of helium-peculiar, HgMn and related stars. Since the helium lines observed have 3He isotope shifts of up to 1 Å and sample a large range of continuous opacities in the program stars, these spectra are being used to search for the presence of 3He in their photospheres and, where 3He is present, examine the possible stratification of both isotopes of helium in their atmospheres. Analysis of a number of previously identified 3He stars provides strong evidence for different vertical stratification profiles of 3He and 4He in these stars. 4He is generally enhanced deep in the photospheres but sharply depleted high in the atmospheres while 3He appears to be confined to a narrow layer above the 4He.

Observational data on the early galactic abundances of the light elements lithium, beryllium and boron are combined with data related to the reionization of the intergalactic medium (IGM) in a search of processes happening in the early universe. Early massive metal-free stars (Pop III), largely held responsible for the reionization of the IGM, are proposed to have been also the injectors of the lithium-6 plateau, through their winds. In this sense the evolution of the 6Li/9Be ratio appears to be a key parameter for the history of nucleosynthesis as a monitor of the early formation of metals and their subsequent injection in high energy particles. 


The low scintillation noise and the long continuous darkness areamong the unique properties of the Dome-C site on the eastAntarctic plateau. Ultra-high precision optical photometry istherefore among the techniques best suited for this particularsite. We propose a telescope (ICE-T) optimized for ultra-high andultra wide field photometry for Dome C. It consists of two 60 cmoptical ultra-wide-field Wynne-Schmidt telescopes and one 18 cmnarrow-field Maksutov spectrophotometric telescope on a singlemount. ICE-T is currently a team effort of the GermanAlfred-Wegener-Institute for Polar Research, the ItalianUniversities of Padova and Perugia, the INAF Observatory Catania,and the Catalonian IEEC in Barcelona, Spain, and the AIP, withcollaboration from the University of New South Wales, Australiaand the University of St. Andrews, UK. In this paper, I discusssome of the many problems associated with sub-milli-magphotometry.

We present “A STEP” (Antarctica Search for Transiting ExtrasolarPlanets), a project dedicated to the search for planetary transitsfrom Antartica. The project consists of a semi-automatic ~40 cmtelescope equipped with a 16-million-pixel CCD installed at DomeC. The site offers crucial assets for a ground-based exoplanet transitsearch: uninterrupted phase coverage, excellent weather, low air-massvariations and reduced scintillation.
This system would be able to detect Pegasids transiting in front ofstars as faint as magnitude sixteen and could also detect smallerplanets in close-in period around brighter stars. This short termproject is meant to be a photometric qualifyer for the site and thefirst stage of a massive detection campaign. A mid-term objective of1000 detections for 2012 could be achieved either with many smalltelescopes or with a large Schmidt telescope with a large field ofview.
The project is relatively simple and cost-effective, and has thedouble purpose of qualifying the site and obtaining first-classscientific results. Our team is already familiar with transitdetection with an automated telescope and cold temperaturequalification.


PLATO is a fully-robotic observatory designed for operation in Antarctica. It generates its own electricity (about 1 kW), heat (sufficient to keep two 10-foot shipping containers comfortably above 0°C when the outside temperature is at -70°C), and connects to the internet using the Iridium satellite system (providing ~30 MB/day of data transfer). Following a successful first year of operation at Dome A during 2008, PLATO was upgraded with new instruments for 2009.

I consider the relation of explanations for the observed data to testability in the following contexts: observational and experimental detection of dark matter; observational and experimental detection of dark energy or a cosmological constant Λ; observational or experimental testing of the multiverse proposal to explain a small non-zero value of Λ; and observational testing of the possibility of large scale spatial inhomogeneity with zero Λ.

This contribution aims to give a brief overview of the nature of the dust in the interstellar medium, its rôle there, where it comes from, what happens to it while it resides there and what are some key outstanding dust issues that yet need further attention.

PAHs are traditionally thought to form around carbon-rich AGB stars,where the presenceof inner-wind shocks and nucleation seeds can aid their formation. However,my recent workhas shown that the formation of benzene – thought to be the rate-limiting step in theformation of larger PAHs – can be efficient in other environments,namely the dense toriaround the evolved stars of pre-planetary nebulae and in the inner regions of theaccretion discs around young stars. I will discuss the chemical pathways to the formationof benzene in these regions and the subsequent formation of larger PAHs.

Interstellar ices are widely observed in the infrared spectra of regions where stars and planetary systems form. Photochemical and thermal evolution of these ices is simulated and studied in our laboratory where the resulting production of complex organic residues is routinely performed. Observations of their variability with slightly different starting chemical conditions can be performed by means of infrared spectroscopy. Organic residues have interesting chemical properties that make them good potential candidates for prebiotic chemistry. Numerous other analytical methods (GC-MS, HPLC, mass spectrometry, etc.) can be combined to refine the knowledge of their chemical composition and structure. We present here some results on the obtained organic residue resulting from subsequent heating and sublimation of the irradiated ices which show the formation of some macromolecular species.

The possible role of neutral PAHs as catalysts for H2 formation in theinterstellar medium is investigated by a combined experimental and density function theorystudy of the superhydrogenation of coronene (C24H12). Thecalculations suggest efficient hydrogenation of both edge and centre sites, along withcompeting abstraction reactions to form H2 in a series of catalytic cycles.Scanning tunneling microscopy and thermal desorption measurements have been used toprovide direct evidence of the formation of superhydrogenated coronene as a result ofexposure to D atoms. Lower limit estimates for the cross-sections of1.8 × 10-17, 5.5 × 10-18 and 1.1 × 10-18 cm2for the formation of singly, doubly and triply hydrogenated coronene are derived. Theresults suggest that superhydrogenated PAHs may play an important role in H2formation in the ISM.