In recent years, astronomical photometry has been revolutionised by space missions such as MOST, CoRoT and Kepler. However, despite this progress, high-quality spectroscopy is still required as well. Unfortunately, high-resolution spectra can only be obtained using ground-based telescopes, and since many interesting targets are rather faint, the spectra often have a relatively low S/N. Consequently, we have developed an algorithm based on the least-squares deconvolution profile, which allows to reconstruct an observed spectrum, but with a higher S/N. We have successfully tested the method using both synthetic and observed data, and in combination with several common spectroscopic applications, such as e.g. the determination of atmospheric parameter values, and frequency analysis and mode identification of stellar pulsations.

We present new parsec-scale resolution data from a multi-phase study of the ISM in the walls of Galactic supershells. Hi synthesis images and CO survey data reveal a wealth of substructure, including dense-tipped fingers and extended molecular clouds embedded in shell walls. We briefly consider formation scenarios for these features, and suggest that both the interaction of an expanding shell with pre-existing dense clouds, as well as in-situ formation of CNM and molecular gas, are likely to be relevant. Future work will also examine the role of instabilities in structure formation and breakup, and will investigate the presence of high-altitude gas associated with supershells and chimneys.

Important progress has been made within the past few years regardingthe theory of low mass stars (m < 1 M⊙) and brown dwarfs(m < 0.075 M⊙).The main improvements concern the equation of state of dense plasmasand the modelling of cool and dense atmospheres,necessary for a correct description of such objects. Thesetheoretical efforts now yield a better understanding of these objectsand good agreement with observations regarding colour-magnitudediagrams of globular clusters, mass-magnitude relationshipsand near-IR colour-magnitude diagrams for openclusters. However uncertainties still remain regardingsynthetic optical colours and the complex problemof dust formation in the coolest atmosphere models.We will present a review of the current success and uncertaintiesof the theory of these objects, which may guide forthcoming projectswith GAIA.

The Origins Billions Star Survey (OBSS) is a space astrometry mission that was funded byNASA in 2004 to perform an eight-month concept study. Although the OBSS mission was notselected for further development beyond the concept study phase, OBSS spawned asmaller-scale mission, called the Joint Milli-Arcsecond Pathfinder Survey (JMAPS), whichis currently funded for launch in early 2014. JMAPS is a small, space-based, all-skyvisible wavelength astrometric and photometric survey mission for 0th through 14th magnitudestars. The primary objective of the JMAPS mission is the generation of an astrometric starcatalogue with better than 1 milliarcsecond positional accuracy and photometry to the 1%accuracy level, or better, at 1st to 12th magnitude.

The Gaia space satellite will perform absolute astrometry, aiming at the definition of aglobal astrometric reference frame at visual wavelengths. Within this reference system, itwill be very difficult to identify possible errors in the measurements or in the datareduction process that brings about the definition of the final catalogue. The Gaia DataProcessing and Analysis Consortium (DPAC) has established an Astrometric Verification Unit(AVU) to verify crucial steps in the baseline data processing chain and report on anysignificant difference. This process is essential in order to guarantee a high qualitycatalogue to the larger scientific community. We describe here the global spherereconstruction (GSR) component of AVU hosted by the Italian data processing centre atTorino (DPCT).

Two competing theories posit that Ultra Compact Dwarfs (UCDs) form either as the stripped nuclei of dwarf galaxies or as giant globular clusters (GGCs) associated with the largest globular cluster (GC) systems. By focussing on the field and group environments where young UCDs may be most common, we have discovered the first UCD that is clearly the result of recent (< 4Gyr ago) stripping of a companion galaxy during a minor galaxy merger. However, we have also found a definitive case of a multiple-UCD system created via GC formation processes, which are likely associated with major galaxy mergers.

By giving three different definitions of peak flux(original peak flux, corrected peak flux, and scaled peak flux), we analyze the frequency distributions of 14057 flares recorded by GOES from 2000 to 2005. We find a significant result that the frequency distribution of the scaled peak flux for all the sample flares can be approximated by a perfect power-law function with an index of 2.18, without any usually deviating from the power-law at the lower fluxes.

We address three timely regression analysis problems in solar-terrestrial observations: the identification of trends in observations that exhibit a high level of internal variability, the choice of explanatory variables in the multilinear regression of climate data, and the identification of power laws in power spectral densities. In all three of them we focus on some common mistakes, and on how these may help facilitate critical reading of research in the field.

We present an analysis of the properties of H i holes detected in 20 galaxies that are part of “The H i Nearby Galaxy Survey”. We detected more than 1000 holes in total in the sampled galaxies. The holes are found throughout the disks of the galaxies, out to the edge of the H i disk. We find that shear limits the age of holes in spirals. Shear is less important in dwarf galaxies which explains why H i holes in dwarfs are rounder, on average than in spirals. Shear is particularly strong in the inner part of spiral galaxies, limiting the lifespan of holes there and explaining why we find that holes outside R25 are larger and older. We proceed to derive the surface and volume porosity and find that this correlates with the type of the host galaxy: later Hubble types tend to be more porous. The size distribution of the holes in our sample follows a power law with a slope of aν ~ −2.9. Assuming that the holes are the result of massive star formation, we derive values for the supernova rate (SNR) and star formation rate (SFR) which scales with the SFR derived based on other tracers. If we extrapolate the observed number of holes to include those that fall below our resolution limit, down to holes created by a single supernova, we find that our results are compatible with the hypothesis that H i holes result from star formation.

Here we present the results of a 3 mm survey of 23 galaxies, obtained with the EMIRreceiver at the IRAM 30 m telescope. Emission of the main molecular species is comparedwith existing chemical models, in order to find and test molecular signatures of galaxyevolution and to compare them to IR evolutionary tracers.

We review the information that planetary nebulae and their immediate progenitors, the post-AGB objects, can provide to probe the nucleosynthesis and mixing in low- and intermediate-mass stars. We emphasize new approaches based on high signal-to-noise spectroscopy of planetary nebulae and of their central stars. We mention some of the problems still to overcome. We emphasize that, as found by several authors, planetary nebulae in low-metallicity environments cannot be used to probe the oxygen abundance in the interstellar medium out of which their progenitors were formed, because of abundance modification during stellar evolution.

A brief review of the terms and definitions related to stellar atmosphere modelling and spectral line formation is presented. In particular, two topics are discussed: the chemical elements that can be treated in a given atmosphere as trace elements, and the scattering processes that are taken into account in line formation modelling.

Galaxy formation and evolution is one of the most challenging tasks in astrophysics. There is strongly increasing and substantial progress in this field not only due to the increase of telescope size and developments of new techniques providing observations allover the electromagnetic spectrum, but also the development of advanced computer architectures and of sophisticated numerical codes allow to tackle this problem from both sides and to link both research approaches to a fruitful progress in astrophysics. This review will not focus on the application of a single numerical method and the description of its result, but is instead aiming at providing an overview of different numerical tools on the basis of particle and grid schemes and to referring to important publications for the intersted reader.

It has been claimed in the past that in low-metallicity Blue Compact Dwarf (BCDs) galaxies, the N/O value is independent of metallicity (O/H ratio), implying the need to invoke a primary production of nitrogen in intermediate-mass stars, in addition to the secondary nitrogen produced from the CNO cycle in high-mass stars. In order to better understand this controversial issue we undertook an integral field spectroscopic study of the nebular gas within a sample of BCDs previously thought to have anomalously high N/O values. Here we present the results of this study for 3 BCDs: two with anomalous N/O values (Mrk 996 and UM 420) and one with more normal N/O values (UM 462). We describe in detail how we derived the physical conditions (Te, Ne) as a function of position within the galaxy, and as a consequence, how this revealed both revised metallicities and normal N/O ratios and uncovered one of the first clear evidences of nitrogen self-enrichment of an H ii  region from WR stars.

It is shown that – in addition to the long-known effect of metallicity on luminosity – the abundance of heavy-elements has an influence on both the light-curve stability of anomalous Cepheids and the period ratio of double-mode Cepheids. Moreover, metallicity is an important controlling factor of the value of the pulsation amplitude of Cepheids.

This paper discusses the opportunities at Dome C for both photometric and spectroscopic asteroseismology. Dome C has two great advantages in this field: the first is the high percentage of superbly photometric skies; the second is the opportunity for long runs, a necessary requirement for asteroseismology. The potential of Dome C for asteroseismology is compared with existing ground-based networks and a potential spectroscopic networks, as well as with space missions.

Receivers for the millimeter and sub-millimeter range employ SIS mixers for the coherent detection of astronomical signals. A very brief overview of the theory of SIS mixers is given, followed bya presentation of recent mixer development at IRAM.

Pi of the Sky is a system of wide field-of-view robotic telescopes which search for shorttimescale astrophysical phenomena, especially for prompt optical GRB emission. The systemis designed for autonomous operation, follows the predefined observing strategy and adoptsit to the actual conditions. We describe the current status of telescopes located in Chileand Spain and prospects for future development.

Within the Cold Dark Matter scenario the hierarchical merging paradigm is the natural result to form massive galactic halos by the minor mergers of sub-halos and, by this, inherently their stellar halo. Although this must be also invoked for the Milky Way, the context of chemical and kinematic coherence of halo stars and dwarf spheroidal galaxies is yet unsolved a focus of present-day research. To examine this issue we model the chemo-dynamical evolution of the system of satellites selected from the cosmological Via Lactea II simulations to be similar for the Milky Way environment but at an early epoch.

Searches for planets around massive stars are essential for developing general understanding of planet formation and evolution of planetary systems. The main objective of the PSU-TCfA Search for Planets around Evolved Stars is detection of planets around G-K subgiants and giants through highly accurate radial velocity (RV) measurements using an iodine absorption cell on the HET HRS spectrograph. However, the long-period radial velocity variations of red giants may also have other causes than planets (e.g. non-radial pulsations or rotational modulation in the presence of starspots). In this work, for the second red giant with planets found in our survey, HD 102272, we present bisector analysis of cross-correlation functions (CCF) constructed from the spectra used for radial velocity determination but cleaned from the iodine lines.