arXiv subjects
Publications and source records attributed to S. K. Balayan.
Observations of Mrk 171, aimed at conduction of panoramic spectroscopy, were undertaken with the Byurakan 2.6-m telescope using spectrograph VAGR. Within the two components of the galaxy, there were differentiated eight condensations of starforming activity, i.e. HII regions, and no sign of AGN activity was revealed inspite of existing suggestions.
The methods of panoramic (3D) spectroscopy are used in a detailed study of galaxies with ongoing star formation chosen from among objects in seven selected fields of the Second Byurakan Survey (SBS). This article deals with the irregular galaxy SBS 1202+583, which our classification scheme identifies as being in a continuous phase of starformation. Observations were made with the panoramic spectrographs MPFS at the 6-m telescope of the Special Astrophysical Observatory (SAO) of the Russian Academy of Sciences and VAGR at the 2.6-m telescope of the Byurakan Astrophysical Observatory (BAO) in Armenia. The data are used to construct charts of the radiative fluxes in the continuum and various emission lines. Special attention is devoted to analyzing the emission in the Hα hydrogen recombination line and in the forbidden low-ionization doublets of nitrogen [NII]λλ6548, 6583 and sulfur [SII]λλ 6716,6731, and the ratios of the intensities of the forbidden lines to Hα. The observable characteristics (sizes, Hα fluxes, etc.) of nine HII regions are studied. The estimated current rates of starformation in the individual HII regions based on the Hα fluxes lie within the range of 0.3-1.2 Msun/year. The dependence of the ratio of the intensities of the emission in these two forbidden doublets on the rate of star formation in the HII regions is found.
To build a large, optically bright, X-ray selected AGN sample we have correlated the ROSAT-FSC catalogue of X-ray sources with the USNO catalogue limited to objects brighter than O=16.5 and then with the APS database. Each of the 3,212 coincidences was classified using the slitless Hamburg spectra. 493 objects were found to be extended and 2,719 starlike. Using both the extended objects and the galaxies known from published catalogues we built up a sample of 185 galaxies with O_APS < 17.0 mag, which are high-probability counterparts of RASS-FSC X-ray sources. 130 galaxies have a redshift from the literature and for another 34 we obtained new spectra. The fraction of Seyfert galaxies in this sample is 20 %. To select a corresponding sample of 144 high-probability counterparts among the starlike sources we searched for very blue objects in an APS-based color-magnitude diagram. Forty-one were already known AGN and for another 91 objects we obtained new spectra, yielding 42 new AGN, increasing their number in the sample to 83. This confirms that surveys of bright QSOs are still significantly incomplete. On the other hand we find that, at a flux limit of 0.02 count /-1 and at this magnitude, only 40 % of all QSOs are detected by ROSAT.
We report the discovery of a new bright (V$\sim$12.6) cataclysmic variable star identified with the ROSAT X-ray source RX J1643.7+3402. Spectroscopic and photometric observations show it to be a novalike variable sharing some of the characteristics of the SW Sex sub-class of novalike CVs. The spectroscopic period may be either 2\fh575 or 2\fh885, within the period "gap." A photometric modulation with a probable period of 2\fh595 and an amplitude of $\sim$ 0.1 mag in V is present on most nights and could be either a "positive" or a "negative" superhump modulation (depending on the exact spectroscopic period), indicating the presence of a precessing accretion disk in this system. Rapid variations of 0.1 to 0.2 mag amplitude in V repeat with a time scale of $\sim$ 15 min.
The data for 100 QSOs from the Second Byurakan Survey (SBS) located on the northern sky 8h < R.A. < 17h and 49deg < Dec. < 61deg are presented. The main parameters of emission lines and the other data for all QSOs as wel as their scans are given. Totally we have found 216 QSOs in SBS.