The installation and operation of an ELT and the associated astronomical instruments requires considering the reliability aspects (the ability to work satisfactorily for a specified time under given environmental conditions) and the maintenance/maintainability aspects from the beginning of an ELT/instrument project.In particular, for equipment working in the extreme antarctic environment the reliability and maintainability characteristics are the main factors influencing, i)the availability of the equipment for the scientific research activities, and ii) the annual and the long term operation costs (Life Cycle Costs, LCC).These characteristics have to be designed and built into the equipment.The presentation describes the general strategy to be followed, the main activities to be done, and the decisions to be taken during the individual project phases from the identification of the user needs to the installation, commissioning and operation in order to guarantee high equipment availability and optimized maintenance effort and costs.

Global hyperbolicity is a classical and well-known concept, whichlies in the core of General Relativity. Here we discuss brieflyfive approaches to this concept. They yield different definitionswhich become natural in diverse contexts: the initial valueproblem, singularity theorems, existence of maximizing causalgeodesics, possibility to split globally the spacetime, causalboundaries. The neat formulation and definitive equivalencebetween these definitions have been completed only recently. Avery brief summary is presented.

I discuss in this contribution constraints on the origin of mass-lossfrom young stars brought by recent observations at high angularresolution (0.1'' = 14 AU) of the inner regions ofwinds from T Tauri stars. Jet widths and collimation scales, the largeextent of the velocity profile as well as the detection of rotationsignatures agree with predictions from magneto-centrifugal disk windejection models. However dynamically cold disk wind solutions predicttoo large terminal velocities and too low jet densities and ionisationfractions, suggesting that thermal gradients (originating in anaccretion heated disk corona for example) may play an importantrole in accelerating the flow.

Weak gravitational lensing has become an important tool to study the properties of dark matter halos around galaxies, thanksto the advent of large panoramic cameras on 4 m class telescopes. Thisarea of research has been developing rapidly in the past few years,and in these proceedings we present some results based on theRed-Sequence Cluster Survey, thus highlighting what can be achieved withcurrent data sets. We present results on the measurement of virial masses as afunction of luminosity and the extent of dark matter halos. Muchlarger surveys are underway or planned, which will result in animpressive improvement in the accuracy of the measurements. However,the interpretation of future results will rely more and more oncomparison with numerical simulations, thus providing direct tests ofgalaxy formation models.

Low-frequency oscillations are unstable in a wide range of stellar models and have been detected in a number of B-type stars. For such modes, even a moderate rotation significantly affects amplitude distribution over stellar surface and hence their visibility conditions. Adopting the traditional approximation, we study effects of rotation on relative amplitudes in photometric passbands and in radial velocity. We present numerical results for unstable modes in a selected stellar model of a 6 M๏ main sequence star. The goal is to show how observable amplitudes, which are tools for mode identification, depend on the rotation rate and on the aspect angle.

The study of the oldest stellar populations in the Galaxy providesimportant cosmological information (e.g. a lower limit to the age ofthe Universe) and helps constraining models of galaxy formation. Themost commonly used stellar age indicators are reviewed and discussed,and the impact of GAIA on these topics is estimated.

In this article we review some of the most recent advances in the modelling and interpretation of molecular line emissions from Galactic and extragalctic environments, in particular from massive star forming regions. Hence We show that observations of extragalactic molecules can potentially be used to infer and disentangle the physical conditions in the gas, as it is already routinely done in our own Galaxy.

The δ Scuti pulsators occupy a region in the Hertzsprung-Russell diagram where several physical processes occur: the subsurface convection layers change from being deep and vigorous to being shallow and ineffective to transport energy. This transition has a large impact not only on pulsational stability but also on stellar evolution, activity, transport of angular momentum, mixing processes, etc.. It is therefore of great interest to understand how exactly the stellar structure changes with increasing temperature and mass. Theoretical models (Houdek et al. 1999; Samadi et al. 2002) predicted that the convection in the outer layers of δ Scuti stars is still efficient enough to excite solar-like oscillations. The Kepler target, HD 187547 (a.k.a. Superstar), was the first δ Scuti star to suggest that solar-like oscillations are indeed present in this type of stars (Antoci et al. 2011). There were several reasons to conclude that HD 187547 is a δ Scuti/solar-like hybrid pulsator. (1) The peaks at high frequencies are modes of pulsations approximately equidistantly spaced, as expected for high radial order pressure modes; these peaks are not combination frequencies as it is sometimes observed in δ Scuti stars. (2) The opacity mechanism cannot excite a continuous frequency range as observed in HD 187547 (Pamyatnykh 2000). (3) The identification as an Am star consistent with the low v sini, makes it very unlikely to be a δ Scuti/roAp hybrid, because strong large-scale magnetic fields, a necessity for roAp pulsators, have never been detected in Am stars (Auriere et al. 2010). (4) Although a large number of Am stars are found in binary systems, we find no evidence in the observed spectra for a companion, i.e. no significant RV shift over 170 days can be detected and the absorption lines can perfectly be reproduced by assuming a slowly-rotating chemically peculiar Am star. This means that the peaks at high frequencies are unlikely to be from a companion, because such a star would be an A or F-type star and would be visible in the spectrum and this is not the case. (5) The large separation Δν, which is the frequency difference between consecutive radial orders of the same degree l, predicts the frequency of maximum power (νmax) to be exactly where the mode with the highest amplitude in the supposed stochastic region is observed. Note that the Δν and νmax scaling relation is valid only for stochastic oscillations (e.g. Huber et al. 2011). (6) The statistical properties (Chang & Gough 1998) of the modes interpreted to be solar-like were very similar to what is expected for stochastic signals in general.

Reference systems and frames are crucial for high precision absolute astrometric work, and their foundations must bewell-defined. The current frame, the International CelestialReference Frame, will be discussed: its history, the use of the groupdelay as the measured quantity, the positional accuracy of 0.3 mas,and possible future improvements. On the other hand, for thedetermination of the motion of celestial objects, accuraciesapproaching 0.01 mas can be obtained by measuring the differentialposition between the target object and nearby stationary sources.This relative astrometric technique uses phase referencing, andthe current techniques and limitations are discussed, usingthe resultsfrom four experiments. Brief comments are included on theinterpretation of the Jupiter gravity deflection experiment ofSeptember 2002.


A recent observation of the Orion Nebula Cluster withthe Chandra X-ray Observatory detected 1075 sources, providing auniquely large and well-defined sample to study the dependence ofmagnetic activity on bulk properties for pre-main sequence (PMS) starsdescending the Hayashi tracks. The principal result is that X-rayemission does not show the activity-rotation relation which is thedominant correlate of magnetic activity indicators in main sequencestars. Instead, other effects are seen in PMS stars: X-rayluminosities are correlated with stellar bolometric luminosity, massand size for M <2-3 M⊙, but the emission drops precipitouslyin some or all PMS stars with M >2-3 M⊙. The absence of an X-ray/rotation correlation in PMS stars, andparticularly the high X-ray values seen in some very slowly rotatingstars, is a clear indication that the mechanisms of magnetic fieldgeneration differ from those operating in main sequence stars. Themost promising possibility is a turbulent dynamo distributed throughoutthe convective zone, but other models such as a "supersaturated"α - Ω dynamo or relic core fields are not immediatelyexcluded. The evidence does not support X-ray production inlarge-scale star-disk magnetic fields. This work is described indetail by Feigelson et al. (2003).

It is now evident that the exceptional seeing at Dome C willallow, in the next years, to pursue astronomical programs withconditions better than at any other observatory in the world, andvery close to space experiments.Considering a new type of wide-field telescope, particularastronomical programs could be well optimized for observations atDome C such as surveys for the discovery and follow up ofnear-Earth asteroids, search for extra-solar planets using transitor micro-lensing events, and stellar luminosity variations.We propose to build a 1.5–2 m class three-reflections telescope, with1–1.5 degree FOV, four times shorter than an equivalent Schmidttelescope, and providing a flat field without requiring atriplet- or quadruplet-lens corrector since its design isanastigmatic.We present the preliminary optical tests of such designs:MINITRUST 1 and 2 are two 45 cm identical prototypes based inFrance and Italy, and manufactured using active optics techniques.

We present the scientific case for a high resolution spectro-imagerin the mid-IR that wouldbe dedicated to the mapping of H2 emission in its four lowest rotational transitions, at 28.2, 17.0, 12.3 and 9.7 micron with a spectral resolution ~104 sufficient to provide kinematical distances ingalaxies. The proposed instrument on a 2 m-class telescope will be most sensitive to H2 line emission simultaneously extended and structured at small scale, in gas at temperatures higher than 80 K. Colder H2,which may contribute most of the baryonic dark matter ingalaxies, will be traced by the emission of glitters of warm H2heated, throughout the medium, by the dissipation of omnipresent turbulence.The main scientific objectives are to (i) directly measure themass and temperature distribution of the warm H2, far from star formingregions, in particular in low metallicity environments where thetraditional tracers of H2 (CO, dust emission) fail, (ii) trace the dissipation of turbulence in the perspective of building a global view of the star formation process in galaxies and (iii)trace baryonic dark matter in the form of cold H2in a large sample of galaxies along the Hubble sequence.

In this paper I give an overview of the numerous ways inwhich rotation and magnetic fields can interact under stellarinterior conditions.I first provide “tutorial”examples of how magnetic fields can (1) alter existing stellarinternal flows, (2) generate internal flows, and of how rotationcan (3) amplify or (4) destroy magnetic fields. The upshot of allthis is that treating rotation or magnetic fields in isolationof one another, as intermediate steps towards the “full picture”,may yield a situation that can only be applied meaningfully undervery limited and specific astrophysical circumstances, if any.

Present studies on the evolution of the Milky Way are driven and shaped by how we conceive its stellar populations, in an on going process started by W. Baade seventy years ago. Despite much progress and advances in our understanding of these populations, inspection of their main properties is however hardly indicative of the path the Milky Way has followed to build up its mass. This is not only a matter of (stellar) age measurement, but more so the consequence of how we interprete the structures that we see in our Galaxy, often through the filter of our definitions of stellar populations. The panorama presented in the following pages opens the possibility that the present “filter” is not fully adequate. I start these Lectures with a summary of the main properties of the disks, bulge, and halo, and then present some of the new directions in the interpretation of the structure and evolution of the disk(s), with emphasis on chemical evolution. I discuss recent results in our understanding of the bulge, its stellar components and chemical evolution. Finally, I present the ideas currently proposed to explain the formation of the Galactic stellar halo. I conclude by examining how deeply all these new results question our present definition of stellar populations.

The science case for FIR/Submm surveys of the extragalactic sky to be carried out from Dome C is reviewed. The main questions concerning the formation and evolution of galaxies making up the CIRB are outlined and opportunities to exploit Dome C unique observing conditions through single-dish observations are discussed.

Contrary to what is still often admitted when studying the chemical evolution of galaxies, the element abundances observed in stellar atmospheres are often not representative of the initial composition of the protostellar nebula. Element abundances may be altered during stellar evolution by atomic diffusion and/or accretion, if not by nuclear reactions. Atomic diffusion occurs in any type of stars, with time scales extremely different according to the macroscopic motions with which they have to compete. Accretion may occur in solar type stars during planetary formation, which seems to be a common process. Following the success of helioseismology, asteroseismology is now becoming a fundamental tool for penetrating the secrets of the internal structure of stars. In particular it may be used to derive their internal abundances compared to the observed ones. In the present paper, I focus on main-sequence stars. I first recall the situations where abundance stratification can act for exciting or stabilizing stellar oscillations, second I describe how seismic observations can be used to derive abundance gradients inside stars.

The complex circumstellar environments associated with several of the most luminous cool supergiants provide evidence for episodic high mass loss events. The origin of the high mass loss is not understood but circumstantial evidence strongly suggests that large scale surface activity and magnetic fields are responsible. I briefly review the observational evidence from multi-epoch imaging and spectroscopy for the high mass loss events and instabilities in these stars. New results from high-resolution AO near and mid-IR imaging of VY CMa, IRC +10420 and μ Cep is also presented.

Asteroseismology requires observables registered in stringent conditions: very high sensitivity, uninterrupted time series, long duration. These specifications then allow to study the details of the stellar interior structure.
Space-borne and ground-based asteroseismic projects are presented and compared. With CoRoT as a precursor, then Kepler and maybe Plato, the roadmap in space appears to be precisely designed. In parallel, ground-based projects are necessary to provide different and unique information on bright stars with Doppler measurements.
Dome C appears to be the ideal place for ground-based asteroseismic observations. The unequalled weather conditions yield a duty cycle comparable to space. Long time series (up to 3 months) will be possible, thanks to the long duration of the polar night.

By means of N-body simulations, we have investigated the impact of minor mergers on theangular momentum content and kinematical properties of a disc galaxy. Our simulationscover a range of initial orbital characteristics and the system consists of a massivegalaxy with a bulge and a stellar disc merging with a much less massive gasless companion.Our results show that: (1) during the process of merging, the disc of the primary galaxybecomes kinematically hotter and thicker; (2) its specific angular momentum alwaysdecreases, independent of the orbit or morphology of the satellite galaxy; (3) thedecrease in the rotation velocity of the primary galaxy is accompanied by a change in theanisotropy of the stellar orbits, which becomes increasingly radially dominated as themerger advances; (4) the radial velocity dispersion increases at all radii, but inparticular in the outermost regions; (5) at the same time, the transverse velocitydecreases throughout the whole disc, except in the inner region, where the constributionof bulge stars leads to an increase ofσt.