We present the essential features of the ANTARES code. ANTARES has been developed to perform the simulation of astrophysical flows in one, two, or three dimensions. Using, in particular, the option of grid refinement, we present results for solar granulation achieved at very high spatial resolution.

Some aspects of power-spectral densities (PSD) of active galactic nuclei are similar to those of galactic black hole X-ray binary systems (McHardy et al. 2005). The signal originates near a black hole and its modulation by general-relativistic effects should be taken into account (Życki & Nedźwiecki 2005). We modified the previous calculations of these effects, assuming a model of spots which occur on the disc surface and decay with a certain lifetime.

Multiwavelengths studies of massive star formation regions in the LMC and SMC reveal that a second generation of stars is being formed in dense molecular clouds located in the surroundings of the massive clusters. These dense molecular clouds have survived the action of massive star UV radiation fields and winds and they appear as compact dense H2 knots in regions of weak CO emission. Alternatively, we have found that large molecular clouds, probably remnants of the parental giant molecular clouds where the first generation of stars were formed, are suffering the interaction of the winds and UV radiation field in their surfaces in the direction of the central massive cluster or massive stars. These molecular regions show 1.2 mm continuum emission form cold dust and they show embedded IR sources as determined from deep ground base JHKs imaging. The distribution of young IR sources as determined from their Mid IR colors obtained by SPITZER concentrate in the maxima of CO and dust emission. IR spectroscopy of the embedded sources with high IR excess confirm their nature as massive young stellar objects (MYSO's). Our results are suggestive of contagious star formation where triggering and induced star formation could be taking place.

The winding up of a conference like this provides the opportunity to look (1) backwards at how we reached the present stage of understanding of binary star behavior and its relationship to the rest of astronomy, (2) around at the garden of unsolved problems, and (3) cautiously forward at what might come next.

Large-scale CO observations with the millimeter/submillimeter telescope NANTEN toward a whole FIR loop-like structure whose angular extent is ~20° × 20° around (l, b) ~(109°, − 45°) in Pegasus have been carried out in the 12CO (J = 1 − 0) at 4′ – 8′ grid spacing and the 12CO emitting region in the 13CO (J=1–0) at 2′ grid spacing. The diameter corresponds to ~25 pc at a distance of 100 pc, adopted from that of the star HD886(B2IV) near the center of the loop.

Incorporating early data from the Suzaku satellite launched in July 2005, properties of Ultra-Luminous compact X-ray sources (ULXs) were studied in close comparison with those of Galactic and Magellanic black-hole binaries. Based on an analogy between these two types of X-ray sources, ULXs showing power-law type spectra are considered to host Comptonized accretion disks, while those with multicolor-disk type spectra are interpreted to harbor “slim” disks. The analogy also suggests that ULXs are radiating near their Eddington limits, and hence their central black holes are significantly more massive than the ordinary stellar-mass black holes contained in Galactic and Magellanic black-hole binaries. In this sense, ULXs can be regarded as intermediate-mass black holes.

We present deep HI observations of a sample of 9 nearby E+A galaxies (0.05 < z < 0.1). In 7 of them, we detected up to a few times 109 M⊙ of neutral gas, making the link between E+As and early-types less direct than previously thought.

Using a semiconvective model based on thermohaline convection, we investigate the case of an expanding core of a main-sequence massive star. The numerical simulations at high Prandtl number show a flow consistent with the assumption that a dynamically neutral layer sits between the core and the radiative envelope. More simulations at low Prandtl number are needed to infer scaling laws applicable to astrophysical regimes.

Integrated spectra of 10 concentrated Galactic open clusters were obtained in the (3600-6800)Å range using the CASLEO (Argentina) 2.15 m telescope. The method used to determine ages and reddening of the clusters consists of the following steps: (1) Estimation of the cluster age from equivalent widths of the Balmer lines. This age is practically independent of the reddening. (2) Choice of the template whose spectral features better resemble those of the observed spectrum. This choice was made by using the libraries of template spectra which were available at the moment of making use of this methodology. In a first approach, the age inferred by the previous method was adopted. (3) Variation of the reddening of the observed spectrum until obtaining the best match to the chosen template. The reddening corrections were done using the normal reddening law. In Table 1 we show the parameters derived here, where the ages values are in Myr.

Five out of the ten studied clusters have not been the subject of previous studies so that their fundamental parameters determined turn out to be the first of their kind. For the remaining clusters, the parameters derived exhibit good agreement with those determined in previous studies.

With the exception of ESO429-SC2, the remaining Galactic open clusters are located within two 90°. sectors centered at l = 343° and l = 253°, respectively. A comparison of the properties of the Galactic open clusters here studied to those of well-known clusters located in the above mentioned sectors, shows that, unless major star forming events had occurred in the Galactic disk in the last 100 Myr or so, the present results would favour an important dissolution rate of star clusters in the above mentioned Galactic sectors.

The exploration of the earliest phase of star and galaxy formation after the Big Bang remains an important challenge of contemporary astrophysics and represents a key science driver for numerous future facilities. During this phase the first stars and galaxies appear and start to light up and ionize the then neutral Universe ending thereby the so called cosmic dark ages and leading progressively to the complete reionization we observe now at redshift z≃6 or earlier.

A194 and A1060 are studied for the nature of point source properties. X-ray to optical luminosity ratios (Lx/Lb) are evaluated for selected galaxies. Cumulative log(N)-log(S) and intrinsic luminosity functions are applied for a comparative evaluation with Lockman Hole. 46 and 32 X-ray point sources are detected by EPIC-PN, for A194 and A1060 respectively. The XLF space density shows significant excess compared to field and local group space density. The result is interpreted as the fueling of AGNs as they enter the ICM from outskirts of the clusters and dimming of the very bright AGNs as they further proceed into cluster core.

We use two methods to establish the relationship between galaxies and dark matter halos. One is based the conditional luminosity function model, which links galaxies and dark matter halos by matching the number density and clustering properties of galaxies with those of dark matter halos in the current CDM model. The second is based on galaxy systems identified from large redshift surveys of galaxies. The galaxy – dark halo relationships established by these two methods match well, and can provide important constraints on how galaxies form and evolve in the universe.

One of the most important results in the study of Globular Clusters (GC) has been the discovery of bimodality in the broad-band colors of many systems. Observations of the Milky Way, M31 and Centaurus A strongly suggest this is a bi-modality in metallicity. One method of constraining, and perhaps better understanding the observed bimodality of GCs is to use semi-analytic models (SAMs) to test both the galaxy and GC formation scenarios. We present the results of a study to test whether SAMs can accurately reproduce the physical characteristics of both the parent galaxy (including luminosity, mass and metallicity) and GC populations. The focus of the work is to test whether the SAMs are capable of reproducing the observed properties of spiral galaxies, in particular the Milky Way and M31, and what, if any, constraints this may place on the formation scenarios of GCs. Among the results are indications that bimodality may be directly connected with reionization at z ~ 7–8.

We present the proper motion study of the thin filaments observed in L'-band (3.8 μm) adaptive optics images of the central parsec of the Milky Way. Observed filaments are associated with the mini-spiral and, in some cases, with stars. They can be interpreted as shock fronts formed by the interaction of a central wind with the mini-spiral or extended dusty stellar envelopes.

Astronomy pupils in Armenia get their first ideas on astronomy at elementary schools. Astronomy as a distinct subject is taught at all secondary schools in the country. Teaching is conducted according to a unified program elaborated jointly by professional astronomers and astronomy teachers. Unfortunately only one hour per week is allotted for teaching astronomy, which obviously is not enough workload to hire specialized astronomy teachers at every school, and at many schools this subject is tutored by non-specialists. Many schools partly compensate this lack of teachers by organizing visits to the Byurakan Astrophysical Observatory (BAO) for pupils, where they also attend short lectures on astronomy. In some schools optional training in astronomy is organized by amateurs, for the purpose of a deeper understanding in astronomy.

During recent years annual competitions for revealing gifted pupils in astronomy have been organized. These competitions have three rounds, namely, in schools, in districts and the final round is, as a rule, held at BAO. The national winners successfully participate in and win prestigious prizes at international astronomical Olympiads as well.

At Yerevan State University (YSU) there is a department for astrophysics, which was set up in 1946 and is operating to date. This department trains specialists for a career in astrophysics. Only one or two students graduate from this department yearly at present, while in the 1980s a dozen specialists were trained every year. BAO serves as the scientific base for the students of YSU as well, and a number of staff members from BAO conduct special courses for YSU students. YSU provides a Master's degree in astrophysics, and BAO is granting a Doctor's (PhD) degree since the 1970s.

In order for the magneto-rotational instability to take place, we need a sufficiently ionized disk. Here, we study, besides viscous dissipation, another heating mechanism for the disk that involves the damping of Alfvén waves due to its interaction with dust grains.

We have obtained high angular resolution spectra on the photometric axes of the stellar spheroid in the polar disk galaxy NGC4650A. We discuss the main implications by the new kinematics on the previous mass models for NGC4650A and on current formation scenarios of Polar Ring Galaxies (PRGs).

16O/17O and 12C/13C ratios in 23 M giants are determined from high resolution IR spectra. The results are confronted with the current models on the convective mixing.

Considerable effort has been spent to determine the period of tidal circularization in close binaries as a function of age, in order to constrain the tidal dissipation theory. A new, direct method of measuring the tidal dissipation by precise timings of periastron passages in eccentric binaries undergoing circularization is proposed. Such binaries with components just leaving the Main Sequence can be found as inner systems in multiple stars. Three examples are given.

Microturbulence is usually treated in model atmospheres as a free parameter (ξt) that allows to re-establish agreement among abundances derived from different lines. Even if this parameter is a consequence of treating a 3D problem as a 1D one, it seems clear that microturbulence is linked to the velocity field within the atmosphere, and therefore to convection in the external layers. The values of the parameter as determined from observations show a dependence both on effective temperature and on surface gravity. In this paper we study how the microturbulence parameter used in the atmosphere models affects the theoretical color-magnitude diagram (CMD). First, in the Main Sequence (MS) domain due to the dependence of the microturbulence parameter on Teff; and second, in the giant branch (Pre-main sequence and Red Giant Branch) where several photometric indexes show a large variation due to the increase of the microturbulence parameter as the stellar gravity decreases. We predict then a significant change in the CMD, as well as in the color-temperature calibrations, if variations of ξt such as those observationally determined are included in theoretical CMD computations.