We simulate the chemodynamical evolution of the Milky Way Galaxy, including the nucleosynthesis yields of hypernovae and a new progenitor model for Type Ia Supernovae (SNe Ia). In our nucleosynthesis yields of core-collapse supernovae, we use light curve and spectral fitting to individual supernovae to estimate the mass of the progenitor, the explosion energy, and the iron mass produced. A large contribution of hypernovae is required from the observed abundance of Zn ([Zn/Fe] ~0). In our progenitor model of SNe Ia, based on the single degenerate scenario, the SN Ia lifetime distribution spans a range of 0.1–20 Gyr with peaks at both ~ 0.1 and 1 Gyr. A metallicity effect from white dwarf winds is required from the observed trends of elemental abundance ratios (i.e., [(α,Mn,Zn)/Fe]-[Fe/H] relations). In our simulated Milky Way-type galaxy, the kinematical and chemical properties of the bulge, disk, and halo are broadly consistent with observations. 80% of the thick disk stars are older than ~8 Gyr and tend to have larger [α/Fe] than in the thin disk.

A method is developed for estimation of the vertical structure of the magnetic field in active regions using multi-wave spectral-polarization measurements of radio waves which gives not only the dependence of magnetic field strength on height but also determines two-dimensional form of a magnetic flux tube, emitted in the microwave range of wavelengths.

We propose a cosmological approach to investigate the formation and evolution of dwarf spheroidal galaxies, satellites of the Milky Way, which allows us to follow self-consistently the dSphs and MW formation, matching simultaneously most of their observed properties.

At low metallicity, B-type stars show lower loss of mass and, therefore, angular momentum so that it is expected that there are more Be stars in the Magellanic Clouds than in the Milky Way. However, till now, searches for Be stars were only performed in a very small number of open clusters in the Magellanic Clouds. Using the ESO/WFI in its slitless spectroscopic mode, we performed a Hα survey of the Large and Small Magellanic Cloud. Eight million low-resolution spectra centered on Hα were obtained. For their automatic analysis, we developed the ALBUM code. Here, we present the observations, the method to exploit the data and first results for 84 open clusters in the SMC. In particular, cross-correlating our catalogs with OGLE positional and photometric data, we classified more than 4000 stars and were able to find the B and Be stars in them. We show the evolution of the rates of Be stars as functions of area density, metallicity, spectral type, and age.

We have obtained infrared spectra of carbon-rich AGB stars in three nearby galaxies – the Large and Small Magellanic Clouds, and the Fornax dwarf spheroidal galaxy. Our primary aim is to investigate gas compositions and mass-loss rate of these stars as a function of metallicity, by comparing AGB stars in several galaxies with different metallicities. C2H2 are detectable from AGB stars, and possibly PAHs are subsequently formed from C2H2. Thus, it is worth investigating chemical processes at low metallicity. These stars were observed using the Infrared Spectrometer (irs) onboard the Spitzer Space Telescope which covers 5–35 μm region, and the Infrared Spectrometer And Array Camera (isaac) on the Very Large Telescope which covers the 2.9–4.1 μm region. HCN, CH and C2H2 molecular bands, as well as SiC and MgS dust features are identified in the spectra. The equivalent width of C2H2 molecular bands is larger at lower metallicity, thus PAHs might be abundant in AGB stars at low metallicity. We find no evidence that mass-loss rates depend on metallicity. Chemistry of carbon stars is affected by carbon production during the AGB phase rather than the metallicities. We argue that lower detection rate of PAHs from the interstellar medium of lower metal galaxies is caused by destruction of PAHs in the ISM by stronger UV radiation field.

A reality of solar global magnetic fields Stokes-meter observations with polarimetric accuracy as high as 10−5 – 10−6, and the dependence of Stokes V profiles on distribution of surface magnetic fields in the central zone of the disk are demonstrated. A possibility to use solar disk-integrated and spatially resolved magnetic fields measurements for testing of magnetic fields mapping methods on Sun-like stars is suggested.

TRUFAS is a wavelet-based algorithm developed for the rapid detection of planetary transits in the frame of the COROT space mission. We present the application of this algorithm to the first two observing fields of CoRoT data. In these, CoRoT has observed a total of about 20000 stars. The first CoRoT observing run, IRa01, covers 2 months, February and March 2007, followed by the 5-months long run LRc01. TRUFAS is a very fast algorithm delivering reliable detections. Here we show the results when TRUFAS was applied to these first two sets of data. In the first run, IRa01, TRUFAS found 10 planet candidates and 143 eclipsing binaries and in the LRc01 10 planet candidates and 124 binaries, with a processing that lasted only one night.

Blue Compact Dwarf (BCD) galaxies are the most metal-deficient star-forming galaxies known in the universe, with metallicities ranging from 1/40 to 1/3 that of the Sun. I review how they constitute excellent nearby laboratories for studying big bang nucleosynthesis and star formation and galaxy evolution processes in a nearly primordial environment.

I discuss three different topics concerning the chemical evolution of the Milky Way (MW). 1) The metallicity distribution of the MW halo; it is shown that this distribution can be analytically derived in the framework of the hierarchical merging scenario for galaxy formation, assuming that the component sub-haloes had chemical properties similar to those of the progenitors of satellite galaxies of the MW. 2) The age-metallicity relationship (AMR) in the solar neighborhood; I argue for caution in deriving from data with important uncertainties (such as the age uncertainties in the Geneva-Copenhagen Survey) a relationship between average metallicity and age: derived relationships are shown to be systematically flatter than the true ones and should not be directly compared to models. 3) The radial mixing of stars in the disk, which may have important effects on various observables (scatter in AMR, extension of the tails of the metallicity distribution, flatenning of disk abundance profiles). Recent SPH + N-body simulations find considerable radial mixing, but only comparison to observations will ultimately determine the extent of that mixing.

Observational and theoretical investigations, performed especially over the last two decades, have strongly attributed the far-UV upturn phenomenon to low-mass, small-envelope, He-burning stars in Extreme Horizontal Branch (EHB) and subsequent evolutionary phases.

Using our new stellar evolution code – a code that follows through complete evolutionary tracks, Pre-MS to cooling WD – without any interruption or intervention, we are able to produce a wide array of EHB stars, lying at bluer (Teff ≥ 20,000 K) and less luminous positions on HRD, and also closely examine their post-HB evolution until the final cooling as White Dwarfs.

HB morphology is a complex multiple parameter problem. Two leading players, which seem to possess the ability to affect considerably positions of HB, are those of: 1.Helium abundance, and 2.mass-loss efficiency on the first giant branch. We focus here on the latter; thus, EHB stars are produced in our calculations by increasing the mass-loss rate on the RGB, to a state where prior to reaching core He flash conditions, only a very small H-rich envelope remains. The core flash takes place at hotter positions on the HRD, sometimes while already descending on the WD cooling curve. We show preliminary results for a range of initial masses (MZAMS = 0.8 − 1.1 M⊙) and for metallicities covering both populations I and II (Z = 0.01 − 0.001). The [M,Z] combinations have been chosen such that the masses would be above and close to typical MS turnoff masses (e.g. the estimation of MTO ≃ 0.85 for NGC 2808), and also so that the ages at HB are of order of 10 ± 5 Gyr.

Comparison of magnetic fields measurements made in different spectral lines and observatories is an important tool for diagnostics of magnetohydrodynamic conditions in the solar atmosphere. But there is a deficit of information about the dependence of results on detailed position on the solar disk, spatial resolution and time. In this study these issues are discussed in application to the solar large-scale and Sun-as-a-star magnetic fields observations.

Using Chandra, XMM-Newton and optical photometric catalogs we study the young X-ray binary (XRB) populations of the Small Magellanic Cloud (SMC). We find that the Be/X-ray binaries (Be-XRBs) are observed in regions with star-formation (SF) rate bursts ~30–70 Myr ago, which coincides with the age of maximum Be-star formation, while regions with strong but more recent SF (e.g., the Wing) are deficient in Be-XRBs. Using the 2dF spectrograph of the Anglo-Australian Telescope (AAT) we have obtained optical spectra of 20 High-Mass X-ray Binaries (HMXBs) in the SMC. All of these sources were proved to be Be-XRBs. Similar spectral-type distributions of Be-XRBs and Be field stars in the SMC have been found. On the other hand, the Be-XRBs in the Galaxy follow a different distribution than the isolated Be stars in the Galaxy, in agreement with previous studies.

The paper presents a new method of an estimation of spatial variations of the magnetic field and superthermal electron distribution in solar cm-radio burst sources. The method is based on the analysis of several burst spectra recorded in the different moments of time and on the minimization of the difference between the theoretical and observed radio fluxes. It is found that the measure of the spatial variations of superthermal electron distribution in the radio source is always greater than that for the magnetic field. In most cases this measure has a minimum at the impulsive phase of cm-radio bursts.

We are conducting multi-transition observations of circumstellar line emission from common molecules such as HCN, SiO, CS, SiS and CN for a large sample of AGB stars with varying photospheric C/O-ratios and mass-loss charachteristics. Our recently published results for SiO and SiS clearly show that major constraints on the relative roles of non-equilibrium chemistry, dust condensation, and photodissociation can be obtained from the study of circumstellar molecular line emission. Presented here are also preliminary results based on detailed radiative transfer modelling of HCN line emission.

Transiting planets manifest themselves by a periodic dimming of their host star by a fixed amount. On the other hand, light curves of transiting circumbinary (CB) planets are expected to be neither periodic nor to have a single depth while in transit, making the Box-Least-Squares (BLS) transit detection method almost ineffective. Therefore, a modified version for the identification of CB planets was developed - CB-BLS. We show that using CB-BLS it is possible to find CB planets in the residuals of light curves of eclipsing binaries (EBs) that have noise levels of 1% or more. Using CB-BLS will allow us to use the massive ground- and space-based photometric surveys to look for these objects. Detecting transiting CB planets is expected to have a wide range of implications. For instance, the frequency of CB planets depends on the planetary formation mechanism - and planets in close pairs of stars provide a most restrictive constraint on planet formation models. Furthermore, understanding very high precision light curves is limited by stellar parameters - and since for EBs the stellar parameters are much better determined, the resultant planetary structure models will have significantly smaller error bars, maybe even small enough to challenge theory.

This short report describes some highlights in extragalactic research over the past three years, and lists the main symposia and meetings in the domain.

We present results of the mid-IR spectra decomposition for planetary nebulae and compact H ii regions in our Galaxy and Magellanic Clouds. The striking correlation between the required PAH component with “7.7” μm band shifted to about 7.8 μm and electron densities of the modeled sources allows us to argue that this PAH component may be in fact PAH anions (PAH−).

The Supernova Working Group was re-established at the IAU XXV General Assembly in Sydney, 21 July 2003, sponsored by Commissions 28 (Galaxies) and 47 (Cosmology). Here we report on some of its activities since 2005.

With the Mie theory and the radiative transfer model, we studied the effect of dust size on the infrared color indexes concerning special filters used in the space infrared missions and typical filters in the near-infrared, of AGB stars with typical oxygen-rich and carbon-rich dust shells. It is found the most affected bands are the near-infrared bands JHK and the Spitzer IRAC bands, meanwhile the wavebands with reference wavelength longer than 10 μm is little affected. The effect increases fast with the mass loss rate. We also discussed the potential to distinguish the O-rich and C-rich dusts, and the difference in IR colors between the AGB stars and other IR sources like YSOs and galaxies.

The X-ray binary population of the SMC is very different from that of the Milky Way consisting, with one exception, entirely of transient pulsating Be/neutron star binaries. We have now been monitoring these SMC X-ray pulsars for over 10 years using the Rossi X-ray Timing Explorer with observations typically every week. The RXTE observations have been complemented with surveys made using the Chandra observatory. The RXTE observations are non-imaging but enable detailed studies of pulsing sources. In contrast, Chandra observations can provide precise source locations and detections of sources at lower flux levels, but do not provide the same timing information or the extended duration light curves that RXTE observations do. We summarize the results of these monitoring programs which provide insights into both the differences between the SMC and the Milky Way, and the details of the accretion processes in X-ray pulsars.