Radio-loud active galaxies in the northern ROSAT All-Sky Survey. IV. Properties of sources stronger than 100 mJy at 5 GHz

We present multi-frequency radio data for 741 extragalactic sources with a 5 GHz integrated flux density of > 100 mJy. These sources have been selected from a cross-correlation of an early ROSAT All-Sky Survey source list with a list of compact radio sources of the 5 GHz Green Bank northern sky survey (RGB sample). The majority of sources were quasi-simultaneously observed with the Effelsberg 100-m telescope at 11 cm, 6 cm, and 2.8 cm. We have determined the spectrum, size and linear polarization properties of these sources. We compare the radio data with ROSAT measurements and optical data. We find that the X-ray selected radio sources, when compared with unbiased radio source samples, are on average slightly more compact, show a higher fractional polarization, a higher absolute rotation measure (RM), and have flatter spectra. Absolute RMs are larger for steep spectrum than for flat spectrum sources and for extended than for compact sources. The average redshift increases with the radio flux density, which indicates that the X-ray selected radio sources have a larger fraction of beamed radio emission. All source characteristics of the sample are in accordance with present unification schemes for AGN, where X-ray selected sources are preferable looked at face on. Tables~1 and 2 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html