X-ray studies of quasars with the Einstein Observatory. III The 3CR sample

Using X-ray emission detected by the Einstein Observatory from each of the 33 3CR quasars in Schmidt's complete sample, it is demonstrated that there is a relationship between the X-ray emission and centimeter wavelength radio emission even for steep-spectrum quasars, provided that only the radio emission from the central object is considered. The observations are summarized, and the estimation of the X-ray luminosity distribution, rather narrow compared to the radio and optical luminosity distributions, is presented. The relationship between X-ray and radio emission is discussed, as is the cosmological evolution of the X-ray luminosity function. The relationship between X-ray and optical luminosity provides an explanation for the finding that X-ray selected quasars have lower redshifts than optically selected quasars of the same optical magnitude.