Abstract. 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 3212 coincidences was classified using the slitless Hamburg spectra. 493 objects were found to be extended and 2719 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 s −1 and at this magnitude, only 40% of all QSOs are detected by ROSAT.
The methods of panoramic (3D) spectroscopy are used by us 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 star formation. 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 maps of the radiative fluxes in the continuum and various emission lines.
Special attention is devoted to analyzing the emission in the Hα
A new sample of some 900 faint IRAS galaxies will be constructed after optical identifications of all IRAS point sources from PSC and FSC in an area with 1500 deg2 at high galactic latitudes. The identifications are being made on the basis of FBS low-dispersion spectra, DSS images and infrared colours. Some 320 IRAS sources have been identified and 180 galaxies have been found. Spectral observations of these objects revealed new AGN and luminous infrared galaxies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.