Physical parameters and classification of eight galactic nuclei from the Second Byurakan Survey

Abstract

Spectroscopic observations with a resolution of 4.5 Angst were performed for a sample of eight galactic nuclei extracted from the Second Byurakan Survey, and one companion galaxy of SBS 1204+505B. The EW and FWHM of the emission lines were measured, and useful line ratios and diagnostic diagrams were used for object classification and reddening estimates. Intrinsic reddening quantities were calculated for all non QSO,i.e. seven objects. Particularly the amount of reddening, BV color excess, extinction coefficient and optical depths in the V band, at Halpha and Hbeta wavelengths, and at 5100 Angst. The broad line region size was also estimated for seven objects, as well as the central black hole masses. Three mass estimates were usually performed for each object and compared. A peculiar line, probably He I lambda 5048, is detected in the QSO SBS 1626+554. Evidence for a stratified narrow line region is found for the two narrow line Seyfert 1 galaxies included in the sample. A revised classification is proposed for two objects, and the companion galaxy of SBS 1204+505B is reported as a nuclear starburst galaxy.