We analyze the statistics and star formation rate obtained in high-resolution numerical experiments of forced supersonic turbulence, and compare with observations. We concentrate on a systematic comparison of solenoidal (divergence-free) and compressive (curl-free) forcing (Federrath et al. 2009 a, b), which are two limiting cases of turbulence driving. Our results show that for the same RMS Mach number, compressive forcing produces a three times larger standard deviation of the density probability distribution. When self-gravity is included in the models, the star formation rate is more than one order of magnitude higher for compressive forcing than for solenoidal forcing.

The nature of the Galactic Ridge X-Ray Emission (GRXE) has been under scientific debate since its discovery more than 30 years ago. It is observed as extended emission along the Galactic disk. The question was: is GRXE truly diffuse or is it composed from a large number of unresolved point sources? Using near-infrared Galaxy maps measured with the DIRBE experiment and data from the INTEGRAL observatory, we show that the galactic background in the energy range 20-60 keV originates from the stellar population of the Galaxy, which is in contrast to the diffuse nature believed before (Krivonos et al., 2007). Here we show preliminary results of studying the transition region from hard X-rays to gamma diffuse background of the Galaxy, revealing the broad band picture of Galactic Background emission.

The first set of Chinese Antarctic telescopes at Dome A is called CSTAR. It consists of four 14.5 cm wide-field telescopes and was installed at Dome A during the traverse of 2007/2008. CSTAR successfully operated for 135 days in 2008 and for more than 200 days in 2009. This paper briefly introduces recent developments in Chinese Antarctic astronomy and their international collaborative activities. It also describes future plans for Dome A, as the building of Kunlun Station began in January of this year.

We present a site testing program initiated at the SUMMIT station on the Greenland Ice Cap. A DIMM was mounted in the SWISS tower, 39 m above the ice level, during a period of 3 weeks in the late Arctic summer 2008. Tracking Polaris, the DIMM obtained continuous seeing measurements. The campaign was hampered by poor weather and the measured seeing was fluctuating, suggesting that the boundary layer was very unstable. However, during short periods, the un-calibrated seeing went below 0″.5, indicating that the free atmosphere seeing above Greenland is not significantly different from what is found above the Antarctic plateau.

We recently presented (Sbordone et al., 2009a) the largest sample to date of lithium abundances in extremely metal-poor (EMP) Halo dwarf and Turn-Off (TO) stars. One of the most crucial aspects in estimating Li abundances is the Teff determination, since the Li I 670.8 nm doublet is highly temperature sensitive. In this short contribution we concentrate on the Teff determination based on Hα wings fitting, and on its sensitivity to the chosen stellar gravity.

An algorithm, MEAD, is presented, which can map extinction in three dimensions, with fine distance and angular resolutions. MEAD is then employed when studying the structure of the outer Galaxy. We show that the Galaxy's radial density profile takes the form of a broken exponential, with density dropping off more steeply beyond a Galacto-centric radius of ~13 kpc.

Understanding how disks dissipate is essential to studies of planet formation. Infrared observations of young stars demonstrate that optically-thick circumstellar disks disappear from around half the stars in low-mass star-forming regions by an age of 3 Myr and are almost entirely absent in 10 Myr old associations (e.g. Haisch et al., 2001). Accretion ceases on the same approximate timescale (e.g. Calvet et al. 2005). The disappearence of gas and dust - planetary building material - places stringent limits on the timescales of giant planet formation. During this crucial interval, planet(esimal)s form and the remaining disk material is accreted or dispersed. Mid-infrared spectrophotometry of protoplanetary disks has revealed a small sub-class of objects in the midst of losing their disk material. These disks have spectral energy distributions (SEDs) suggestive of large inner gaps with low dust content, often interpreted as a signature of young planets. Such objects are still rare although Spitzer surveys have significantly increased the number of known transitional objects (e.g. Brown et al. 2007, D'Alessio et al., 2005). However, spectrophotometric signatures are indirect and notoriously difficult to interpret as multiple physical scenarios can result in the same SED. Recent direct imaging from millimeter interferometry has confirmed the presence of large inner holes in transitional disks, providing additional constraints and lending confidence to current SED interpretations (Brown et al. 2008, Brown et al. 2009, Andrews et al. 2009, Isella et al., 2009).

We performed a 1D LTE chemical abundance analysis of an extremely metal-poor star BD+44°493 ([Fe/H]= −3.7), and set a very low upper limit for its Be abundance: A(Be) < −2.0. It may indicate that the decreasing trend of Be abundances with lower [Fe/H] still holds at [Fe/H] < −3.5, and demonstrate that high C and O abundances do not necessarily imply high Be abundances. However, since the star is a subgiant with Teff ~ 5500K, Be may be depleted.

Ultra-luminous infrared galaxies (ULIRGs; L > 1012 L⊙) are quite rare in the local universe, but seem to dominate the co-moving energy density at z > 2. Many are optically-faint, dust-obscured galaxies that have been identified only relatively recently by the detection of their thermal dust emission redshifted into the sub-mm wavelengths. These submm galaxies (SMGs) have been shown to be a massive objects (M* ~ 1011 M⊙) undergoing intense star-formation(SFRs ~ 102 − 103 M⊙ yr−1) and the likely progenitors of massive ellipticals today. However, the AGN contribution to the far-IR luminosity had for years remained a caveat to these results. We used the Spitzer Infrared Spectrograph (IRS) to investigate the energetics of 24 radio-identified and spectroscopically-confirmed SMGs in the redshift range of 0.6 < z < 3.2. We find emission from Polycyclic Aromatic Hydrocarbons (PAHs) – which are associated with intense star-formation activity – in >80% of our sample and find that the median mid-IR spectrum is well described by a starburst component with an additional power-law continuum representing < 32% AGN contribution to the far-IR luminosity. We also find evidence for a more extended distribution of warm dust in SMGs compared to the more compact nuclear bursts in local ULIRGs and starbursts, suggesting that SMGs are not simple high-redshift analogs of local ULIRGs or nuclear starbursts, but have star formation which resembles that seen in less-extreme star-forming environments at z ~ 0.

Current theories that seek to unify gravity with the other fundamental interactions suggest that spatial and temporal variation of fundamental constants is a possibility, or even a necessity, in an expanding Universe. Several studies have tried to probe the values of constants at earlier stages in the evolution of the Universe, using tools such as big-bang nucleosynthesis, the Oklo natural nuclear reactor, quasar absorption spectra, and atomic clocks (see, e.g. Flambaum & Berengut (2009)).

Helioseismology has provided us with the unique knowledge of the interior structure and dynamics of the Sun, and the variations with the solar cycle. However, the basic mechanisms of solar magnetic activity, formation of sunspots and active regions are still unknown. Determining the physical properties of the solar dynamo, detecting emerging active regions and observing the subsurface dynamics of sunspots are among the most important and challenging problems. The current status and perspectives of helioseismology are briefly discussed.

In the next few years, both Herschel and ALMA will be providing unique new insights into the physics and chemistry of protoplanetary disks. In particular, they will be used to study how disks evolve from massive embedded systems around young Class 0 objects, through low-mass disks around optically-visible T Tauri stars, to debris disks around stars on the main-sequence. Gas dominates the mass in the younger systems, but in debris systems there is very little - if any. How does the gas disappear, what is the effect of this on planetary formation, and what is the role of “transition” disks? I outline some of the areas where these two large facilities will contribute to these studies, focussing on the Herschel Key project, GASPS, and looking forward to the role of ALMA.

The special session aims at discussing an integrated approach of the different efforts to increase and promote the teaching and learning of astronomy in the world, with emphasis on developing countries. To this end, attention will be given to research on education, specifically in the field of physics, to best practices of the use of astronomy in educational systems (specifically in developing countries), and to innovative learning initiatives other than formal education. The Special Session aims also at creating a universal perspective wherein modern (post-Copernican) astronomy will presented as an intellectual cumulus. The objective of the session is to disseminate best practices in teaching and learning activities of astronomy and to give an opportunity to learn about initiatives in different cultural and socio-economic settings. The special session also wants to give food-for-thought and proposals for reflection for an integrative approach, and for optimization processes, to enhance the interest in astronomy and its role as a trigger towards science education in the educational systems, with emphasis on the developing countries. The outcome should be a sensitization of teachers and students alike to the concept of a universal history of astronomy and creation of some reliable source material which can be used as a teaching aid in a culture-specific context. The outcome could be a set of recommendations for future integrated actions, and eventually recommendations on new initiatives, framed into the new decadal policy plan.

We present a new solution of Earth Orientation Parameters, based on optical astrometry and catalog EOC-4.

We present Li abundances for 73 stars in the metallicity range −3.5 < [Fe/H] < −1.0 using improved IRFM temperatures (Casagrande et al. 2010) with precise E(B-V) values obtained mostly from interstellar NaI D lines, and high-quality equivalent widths (σEW ~ 3%). At all metallicities we uncover a fine-structure in the Li abundances of Spite plateau stars, which we trace to Li depletion that depends on both metallicity and mass. Models including atomic diffusion and turbulent mixing seem to reproduce the observed Li depletion assuming a primordial Li abundance ALi = 2.64 dex (MARCS models) or 2.72 (Kurucz overshooting models), in good agreement with current predictions (ALi = 2.72) from standard BBN. We are currently expanding our sample to have a better coverage of different evolutionary stages at the high and low metallicity ends, in order to verify our findings.

Astronomy is an attractive subject for education. It deals with fascination of the unknown and the unreachable, yet is uses tools, concepts and insights from various fundamental sciences such as mathematics, physics, chemistry, biology. Because of this it can be well used for introducing sciences to young people and to raise their interest in further studies in that direction. It is also an interesting subject for teaching as its different aspects (observation techniques, theory, data sampling and analysis, modelling,?) offer various didactical approaches towards different levels of pupils, students and different backgrounds. And it gives great opportunities to teach and demonstrate the essence of scientific research, through tutorials and projects. In this paper we discuss some of the challenges education in general, and astronomy in particular, faces in the coming decades, given the major geophysical and technological changes that can be deducted from our present knowledge. This defines a general, but very important background in terms of educational needs at various levels, and in geographical distribution of future efforts of the astronomical community. Special emphasis will be given to creative approaches to teaching, to strategies that are successful (such as the use of tutorials with element from computer games), and to initiatives complementary to the regular educational system. The programs developed by the IAU will be briefly highlighted.

We show that the current data of the HB branch of 47 Tuc show a particular feature that cannot be explained if a single population with an unique mechanism of mass loss is considered. We find that a spread in helium abundance among the stars is necessary, of ~0.02. We indicate that the same variation in helium is present among the sub giant branch stars and suggest that is responsible of the spread in luminosity of the bright sub giant branch, while only a small part of the second generation is characterized by C+N+O increase and gives the faint sub giant branch.

We examine the effects of thermohaline mixing on the composition of the envelopes of low-metallicity asymptotic giant branch (AGB) stars. We have evolved models of 1, 1.5 and 2M⊙ and of metallicity Z = 10−4 from the pre-main sequence to the end of the thermal pulsing asymptotic giant branch with thermohaline mixing applied throughout the simulations. We find that the small amount of 3He that remains after the first giant branch is enough to drive thermohaline mixing on the AGB and that the mixing is most efficient in the early thermal pulses, with the efficiency dropping from pulse to pulse. We note a surprising increase in the 7Li abundance, with log10ϵ(7Li) reaching values of over 2.5 in the 1.5M⊙ model. It is thus possible to get stars which are both C- and Li-rich at the same time. We compare our models to measurements of carbon and lithium in carbon-enhanced metal-poor stars which have not yet reached the giant branch. These models can simultaneously reproduced the observed C and Li abundances of carbon-enhanced metal-poor turn-off stars that are Li-rich.

We use test-particle orbit integration with a realistic Milky Way (MW) potential to study the effect of the resonances of the Galactic bar and spiral arms on the velocity distribution of the Solar Neighbourhood and other positions of the disk. Our results show that spiral arms create abundant kinematic substructure and crowd stars into the region of the Hercules moving group in the velocity plane. Bar resonances can contribute to the origin of low-angular momentum moving groups like Arcturus. Particles in the predicted dark disk of the MW should be affected by the same resonances as stars, triggering dark-matter moving groups in the disk. Finally, we evaluate how this study will be advanced by upcoming Gaia data.

Luminous infrared galaxies (LIRGs) emit most of their radiation in the infrared region of the spectrum in the form of dust thermal continuum, with typical luminosities of LIR > 1010 L⊙. The central power source responsible for the total energy output is deeply buried in the dusty central regions of these objects and its origin still unclear. Recent studies by Spoon et al. (2007) and Aalto et al. (2007) suggest that some LIRGs might represent early obscured stages of active galaxies, either AGNs or starbursts, and thus play a fundamental role in galaxy formation and evolution.