HCGs: stable and rotating systems?

It is shown that the radial velocity dispersion of the elongated HCGs (b/a ≤ 0.2) with smaller two‐dimensional galaxy‐galaxy median projected separation R is, on average, higher than those of the groups with larger R. It shows that galaxies in a group move preferentially along its elongation. Inspection of radial velocities of member galaxies in chain‐like and in roundish HCGs shows that galaxies in HCGs most probably rotate around the gravitational center of the corresponding group. Other two possible mechanisms: flying apart of galaxies from the group in opposite directions, and infall of field galaxies upon the group are excluded. It follows that HCGs are, probably, more stable formations, than it has been assumed. In this case the known inconsistencies between the results of the N‐body simulations and the observational facts are being excluded.     

Photometric and spectroscopic study of the Shakhbazian compact galaxy groups ShCG 254, ShCG 257, ShCG 351, and ShCG 371

Results of a detailed spectroscopic and photometric study of the four Shakhbazian compact galaxy groups ShCG 254, ShCG 257, ShCG 351, and ShCG 371 are reported. The redishifts of the member galaxies and radial velocity dispersions in these groups have been determined. The R surface brightness distributions of the member galaxies have been studied. The morphological types of the galaxies have been determined based on the profiles of the surface brightness, μ, as functions of the semimajor axis α^1/4 or α. Some members of the groups are in the process of interacting. Curves of isophotal twisting and the Fourier parameter α₄ have been plotted. The physical parameters of the groups (radial velocity dispersions, virial radii and masses, luminosities, mass-to-luminosity ratios, and crossing times) have also been derived. Original Russian Text ? H.M. Tovmassian, H. Tiersch, V.O. Chavushyan, G.H. Tovmassian, S.I. Neizvestnyĭ J.P. Torres-Papaqui, G.M. Rudnitskii. 2006, published in Astronomicheskiĭ Zhurnal, 2006, Vol. 83, No. 11, pp. 963–975.     

The New Seismic Zonation Map for the Territory of Armenia

In the present work a new, deterministic, seismic zonation map for the territory of Armenia is presented. It has been compiled on the basis of the newest seismological, geological and geophisical data. Creation of the map included: determination of a seismic hazard area for the territory of Armenia; compilation of a map of active faults; identification of active blocks; identification of seismic source zones; calculation of a seismic effect from the seismic source zones (SSZs). Seismic effect on the Earth's surface from the singled out SSZs is calculated in the form of an intensity of seismic influences expressed in units of MSK-64 scale, and horizontal soil accelerations expressed in fractions of gravity force acceleration (g). The map compiled will allow comparison between the deterministic model with a probabilistic seismic zonation model for the territory of Armenia (in preparation), in order to analyze the western and eastern standards of seismic hazard assessment on the basis of the same complete data base.     

Isolated Shakhbazian compact groups

It is more appropriate to study the dynamics and evolution of compact groups using a sample of isolated compact groups in the nearby vicinity of which there are no accordant redshift galaxies. To look for isolated compact groups we inspected the environment of 78 Shakhbazian compact groups, with known redshifts. We found that 26 of nearby groups with V < 40000 km s⁻¹ are isolated compact groups in the vicinity of which up to a projected distance of 1 Mpc there are no accordant redshift galaxies. For four of them, the redshift of only two members are known, so their being groups is not certain. In the vicinities of eleven distant groups (V > 40000 km s⁻¹) no accordant redshift galaxies are detected as well. The reason for this may be the faintness of galaxies there. These groups may possibly be isolated.     

On the Problem of the Galaxy Alignment with Groups and Clusters

Astrophysics - The study of the alignment of galaxy groups of the Tempel, Tago &amp; Liivamägi (2012) catalog showed that detection of the alignment of the group galaxies with the group...     

On the Possible Explosion in the Carina Nebula

The consideration of the additional data on the distribution of OB stars, of the dust matter (the IRAS data at 100 m, and of the results of observations 120–300 m), of the X-ray emission, of the continuum radio emission, and of the data on the proper motions of stars in the Carina nebula, proved the made suggestion (Tovmassian et al., 1993, 1994), that the observed specific distribution of the mentioned objects in the Carina nebula could be due to some explosion which took place in its central region.     

Ultraviolet observations in Puppis with the space telescope ‘Glazar’

The results of observations of 159 stars at 1640 Å in Puppis made with the space telescope Glazar are presented. It is shown that the observed stars are members of different groups of stars situated at distances of about 120, 370, 700, 1250, 2400, and 4000 pc. The last two groups belong to the Pup OB1 and the Pup OB2 stellar associations.There is relatively little absorption in the observed region. The absorbing matter is mainly concentrated in small clouds.It is suggested that three stars — CP –27°4197, HD 60479, and HD 61672-are embedded in a dust envelope and that the star HD 60057 has a hot subdwarf companion.Forty-four of the observed stars are new OB or early A-type stars, spectral types of which were not known.