Beaming and the X-ray, optical and radio properties of quasars

Abstract

We examine the correlations of X-ray and optical luminosities with radio properties for radio-selected quasars. A remarkably strong correlation is found to exist between the total radio luminosity (irrespective of whether it comes from a compact core or extended lobes) and the X-ray luminosity. A weaker correlation is found between the radio luminosity and the optical luminosity. The results are consistent with a two-component origin for the optical/X-ray emission, one isotropic and one relativistically beamed. This model also accounts for the change of slope with radio structure for the radio/X-ray luminosity correlation noted by Kembhavi et al. Quasars with flat radio spectra are found to have smaller emission-line equivalent widths than do steep-spectrum quasars, again in the sense predicted by the beaming hypothesis.