Spectroscopy and Photometry of Stellar Objects from the Second Byurakan Survey

Abstract

The results of spectroscopic observations of 202 stellar objects, and photometric observations of 171, from the Second Byurakan Survey (SBS) are reported. The SBS sample has proved to be a rich source of newly identified quasars, Seyfert-type galaxies, degenerate stars, and hot subdwarfs. In this subsample we have identified 71 new QSOs; one BL Lacertae object; one Seyfert 1 galaxy; one LINER; one blue compact galaxy; 31 white dwarfs (WDs), 25 of DA type and six of DB type; 26 subdwarfs; 11 horizontal-branch B-type, 11 normal/horizontal-branch, 18 G-type, and 11 F-type stars; 10 objects with composite spectra; two cataclysmic variables; and six objects with continuous spectra. Among the 71 QSOs, we have found three broad absorption line QSOs, namely, SBS 1139+534, 1524+517, and 1524+491, and one damped Lyα QSO, SBS 1425+606. The very luminous objects have visual magnitudes in the range 15.9 MV > -31.5. A number of the low-redshift SBS QSOs show strong Fe II complexes at rest wavelengths of 4570, 5190, and 5320 A. We present accurate positions, spectral classifications, and magnitudes for all objects. The redshifts, equivalent widths, and spectra for QSOs and emission-line galaxies are given, as are some typical spectra for hot stars. The vast majority (63%) of stellar objects selected in the SBS turned out to be WDs (36%) and sdB subdwarfs (27%). Only ~5%–7% of objects with B < 16.4 and ~13% with B ~ 17.0 were identified as QSOs. In total, 470 QSOs and ~500 hot stars were discovered in the course of the SBS. The lower limit on the surface density of bright QSOs in the redshift range 0.3 < z < 2.2 is no fewer than 0.06 deg-2 for B < 17.0 and 0.13 deg-2 for B < 17.5. The surface density of DA WDs is estimated to be 0.06 deg-2 for B < 16.0 and 0.14 deg-2 for B < 17.0.