The cross-correlation of the source list from the ROSAT All-Sky Survey with the 5 GHz Green Bank survey yields a list of 2127 objects. About two thirds of them are optically unidentified. The majority of the objects with known optical counterparts are quasars and radio galaxies, most of them detected in X-rays for the first time. In this paper we present a list of the previously optically identified objects with their main characteristics and discuss their general (bulk) properties. We find strong correlations between luminosities in the radio, optical, and X-ray bands which differ for quasars and radio galaxies.
ROSAT spectra of 86 Active Galactic Nuclei (AGN) with a broad range of optical FeII strengths have been analyzed. The results of the spectral analysis have been combined with optical and radio data as well as with optical emission line properties collected from the literature to understand the origin of the strong FeII emission and the nature of the soft X-ray excess.
