Angular momentum is playing a key role during the collapse of prestellar cores since it is leading to disk formation and to some extent to binary formation. On the other hand, it has long been recognized that the stars possess a tiny fraction of the initial momentum that their parent clouds retain, an issue known as the “angular momentum problem”. In these lectures, we attempt to present the most recent calculations performed to investigate the angular momentum transport and the influence angular momentum has, during the collapse of prestellar cores. After a brief introduction of the star formation context and a broad description of the important features within collapsing cores, we discuss the so-called catastrophic braking. Indeed when magnetic field and rotation axis are aligned, the magnetic braking is so efficient that the formation of early disks is completely prevented. We then present the various studies which have attempted to explore the robustness of this efficient transport including influence of non-ideal MHD, misalignment between magnetic field and rotation axis and turbulence. While the role of the first, is not entirely clear; the two other effects diminish the efficacity of the magnetic braking making the issue less severe than in the pure ideal MHD aligned configuration. Finally, we discuss the fragmentation of low and high mass cores with particular emphasis on the impact of the magnetic field. In particular, we discuss the drastic stabilization that magnetic field has on low mass cores and the possible solution to this apparent conundrum. In the context of high mass stars, its influence is much more limited reducing the number of fragments by a factor of the order of two. However when both radiative feedback and magentic field are included, the fragmentation is very significantly reduced.

Large millimetric and submillimetric telescopes can play a crucial role in our understanding of the Universe, allowing the direct measurement of early galaxies or the investigation of the earliest stages of star formation. The B modes of CMB polarization are a direct probe of the Inflationary epoch and their measurement promises to provide information on the scale of energies at which the process took place. For these investigations (and many others), large detectors arrays with thousands of pixels are needed, to achieve high mapping speeds. This is especially true in the case of mm and sub/mm observations from extremely cold and dry locations like Dome-C, where ultra-low temperature detectors, reaching photon noise limited performance, are needed to fully exploit the excellent quality of the site. In this paper we present the working principle of the Microwave Kinetic Inductance Detectors and their status of development in Italy, focusing on the key aspects that make them ideal for large arrays of sensors.

Energy, and more generally conserved charges, is a subtle issue in general relativity and it is subject to controversy. Indeed, there aremany different definitions in the literature and in some cases they do not all give the same charges. For example, as emphasized byGibbons, et al. (2005), not even in four dimensions do all authors obtain the same expression for the energy of Kerr-AdS black holes and some of these expressions are in disagreement with the first law of black hole thermodynamics. I adopted in [arXiv:0705.0484] the method formulated by Regge & Teitelboim (1974). Based on the Hamiltonian formulation of gravitation, it associates to each asymptotic Killing vector a conserved charge without having to make any arbitrary choice. The charge is then expressed as a surface integral over a 2-sphere at spatial infinity. I investigate here conserved charges and asymptotic symmetries in both asymptotically flat and AdS spaces in arbitrary spacetime dimensions. The study is presented in general coordinates, including the ellipsoidal coordinates that are well adapted to the Kerr solution.

PILOT (Pathfinder for an International Large OpticalTelescope) isa proposed 2 m class optical/infrared telescope to be sited atDome C on the Antarctic plateau. Recent site testing results fromDome C have shown remarkable ground level seeing, a largeisoplanatic angle, and a long atmospheric coherence time. Thesefactors significantly improve the resolution and increase thecapabilities of adaptive optics systems. Additionally, the low skyemission at Dome C gives a significant increase in infraredsensitivity compared to typical mid-latitude sites. PILOT isenvisaged as a winterised version of a commercially available 2 mclass telescope, with a simple low cost dome (sufficient for thelow ground level wind speeds), and a tip-tilt and/or a deformablesecondary mirror. A number of science cameras covering the visibleto the sub-millimetre are being considered.

A very brief introduction to the theory of line broadening is presented.

We present preliminary results of the measurements of sky transparency conducted at Dome C during the winter 2008. Using MOLIERE modeling, we estimate a low precipitable water vapour content above Concordia station, which is very promising for future submillimetre wave observations on the Antarctic Plateau.

In low-mass disks, turbulent torques are probably the most importantway of redistributing angular momentum. Here we present the theory ofturbulent accretion disks. We show the molecular viscosity is far toosmall to account for the evolutionary timescale of disks, and wedescribe how turbulence may result in enhanced transport of (angular)momentum. We then turn to the magnetorotational instability, whichthus far is the only mechanism that has been shown to initiate andsustain turbulence in disks. Finally, we present both the basis andthe structure of α disk models.

We demonstrate the eclipsing binary detection performance of the Gaia variability analysis and processing pipeline using Hipparcos data. The automated pipeline classifies 1 067 (0.9%) of the 118 204 Hipparcos sources as eclipsing binary candidates. The detection rate amounts to 89% (732 sources) in a subset of 819 visually confirmed eclipsing binaries, with the period correctly identified for 80% of them, and double or half periods obtained in 6% of the cases.

The gain of thermal infrared instruments in the 2–25 μm wavelength range from Antarctica is summarized by comparing three parameters: the ambient temperature; the atmospheric transparency, with perceptible water vapor content (PWV) in particular; and the image quality. For the 2 m class infrared telescope projects at Dome C the estimated mid infrared point source sensitivity can be compared to the sensitivities reached at 10 m class telescopes elsewhere. This comparison favors a thermal IR instrument at Dome C with focus on key science cases; two examples are: i) Survey type projects, such as mid infrared photometric imaging or spectro–polarization campaigns of YSO. Or ii) monitoring and rapid response observations on the Galactic Centre, the LMC, SN or GRB.

An overview is given of the capabilities of the HIFI instrument on board of the HerschelSpace Observatory, its observing modes and its calibration. With the superb spectralresolution and wide frequency coverage of HIFI a plethora of astrophysical studies aredone.

We simulated the data outputs of the first Japanese astrometry satellite Nano-JASMINE,which is scheduled to be launched by the Cyclone-4 rocket in August 2011. The simulationswere carried out using existing stellar catalogues such as the Hipparcos catalogue, theTycho catalogue, and the Guide Star catalogue version 2.3. Several statics are shown suchas the number of stars those will be measured distances using annual aberrationobservations. The method for determining the initial direction of the satellite’s spinaxis has also been discussed. In this case, the frequency of bright stars observed by thesatellite is an important factor.

Due to the non-commutation of spatial averaging and temporal evolution, inhomogeneities and anisotropies (cosmic structures) influence the evolution of the averaged Universe via the cosmological backreaction mechanism. We study the backreaction effect as a function of averaging scale in a perturbative approach up to higher orders. We calculate the hierarchy of the critical scales, at which 10% effects show up from averaging at different orders, observable up to scales of 200 Mpc. The cosmic variance of the local Hubble rate is 10% (5%) for spherical regions of radius 40 (60) Mpc. We compare our results to the Hubble Space Telescope (HST) Key Project data.

Close hierarchical triple stellar systems offer a unique possibility to study not only theoretically, but even observationally (at least with limitations) the interaction between a non-spherical and temporally variable gravitational field and the internal structures of the stars. From this purpose a new numerical integrator was developed for studying the orbital and spin evolution of hierarchical triple stellar systems. The code includes equilibrium tide approximations with arbitrary direction of rotational axes. The variation of the orbital elements (e.g. the inclination of the close -eclipsing- binary) and its observational consequences according to the distorted models with different mass-distributions of the stars, as well as with and without dissipation, is studied in the case of the well-known eclipsing triple system Algol. We found that in the absence of dissipation the third star may cause sudden fluctuations in the orbital elements and in the rotation of the binary components, even if they were previously synchronized. Tidal dissipation can eliminate these fluctuations; nevertheless certain variations may subsist, and they could explain some effects that have been observed in several eclipsing binaries.

This work concerns the study of the properties of convective cores in main-sequence models of solar-like pulsators and what information they may hold about stellar ages. We verified that the maximum absolute frequency derivative of particular combinations of frequencies, which we name “the slopes”, provides information on the relative size of the discontinuity in the sound-speed profile at the border of the convectively mixed region. Since the latter is related to the evolutionary state of stars, we show that for models with masses above 1.3M⊙, it may be possible to estimate the fraction of stellar main-sequence evolution from the slopes. Moreover, for models with masses below 1.2M⊙ we verified that it may be possible to use the slopes to discriminate against models with small amounts of core overshoot.

We investigate the occurrence of water vapour signatures in a total of 10 red giants in the solar neighbourhood at mid-infrared wavelengths (12 μm). With the use of high resolution spectra from TEXES and synthesized spectra based on MARCS model atmospheres, we analyse the differences and discuss plausible causes. These include abundance adjustments, the addition of non-photospheric components (MOLspheres) and a different temperature profile.

Stars are not smooth. Their photosphere is covered by a granulation pattern associated with the heat transport by convection. The convection-related surface structures have different size, depth, and temporal variations with respect to the stellar type. The related activity (in addition to other phenomena such as magnetic spots, rotation, dust, etc.) potentially causes bias in stellar parameters determination, radial velocity, chemical abundances determinations, and exoplanet transit detections.

The role of long-baseline interferometric observations in this astrophysical context is crucial to characterize the stellar surface dynamics and correct the potential biases. In this Chapter, we present how the granulation pattern is expected for different kind of stellar types ranging from main sequence to extremely evolved stars of different masses and how interferometric techniques help to study their photospheric dynamics.

We report a study of the relation between dust and gas over a 100 deg2 area inthe Taurus molecular cloud. We compare the H2 column density derived from dustextinction with the CO column density derived from the 12CO and 13COJ = 1 → 0 lines. We derive the visual extinction from reddeningdetermined from 2MASS data. The comparison is done at an angular size of 200′′,corresponding to 0.14 pc at a distance of 140 pc. We find that the relation between visualextinction AV and N(CO) is linear betweenAV ≃ 3 and 10 mag in the region associated with theB213–L1495 filament. In other regions the linear relation flattens forAV ≳ 4 mag. Accounting for the observed relation between thecolumn density of CO and CO2 ices and AV, we find alinear relationship between the column of carbon monoxide and dust for observed visualextinctions up to the maximum value in our data  ≃23  mag.

We use the combination of the very large Millennium and Millennium-II simulations to follow galaxy formation over a stellar mass range of more than five orders of magnitude throughout representative cosmological volumes. These are the first simulations to address the abundance and spatial distribution of galaxies ranging from cD’s down to dSph’s. We demonstrate that stronger feedback is needed than in previous models, epically at low mass, if the SDSS stellar mass function is to be matched in a LCDM universe. Models which satisfy this constraint also reproduce the observed abundance of faint dwarfs around the Milky Way and M 31. Only the very faintest objects are significantly affected by the treatment of reionisation. Our model can reproduce most galaxy properties in the local Universe. Problems remain with respect to the stellar age distributions and kinematics of dwarfs.