X-ray and radio core emission in radio quasars

Abstract

In order to investigate the physical relationship between X-ray and radio core emission in radio-selected quasars, we have observed with the Very Large Array, 35 radio quasars at 6 and 20 cm. The sample was chosen from a list of radio quasars with known X-ray luminosity but poorly known radio properties. Including data gathered from the literature, we now have radio core detections or upper limits at 6 cm for 127 radio quasars which have published Einstein X-ray data. We have sought statistical association between radio core luminosity and X-ray luminosity, and find that there is a strong correlation. The slope of the relation L(x) ~L_Γ^α is α=0.71±0.07 for unresolved quasars with flat radio spectra. The slope decreases as quasars with extended radio regions are considered. We trace this to the presence of radio emission which is unrelated to the X-ray emission, in the presently unresolved cores of quasars.