The radio luminosity-black hole mass correlation for quasars from the first bright quasar survey and a "unification scheme" for radio-loud and radio-quiet quasars

Several independent lines of evidence now point to a correlation between bl ack hole mass M-bh and radio luminosity. In this Letter, we discuss the cor relation for quasars from the FIRST Bright Quasar Survey (FBQS) using black hole mass estimates from H beta line widths. The FBQS objects fill in the gap between the radio-loud and radio-quiet quasars in the radio luminosity- optical luminosity plane, and we find that they fill the corresponding gap in the M-bh-radio luminosity correlation. There is thus a continuous variat ion of radio luminosity with M-bh, and no evidence for a "switch" at some s et of critical parameter values that turns on powerful radio jets. By combi ning the FBQS data with that for quasars from the Palomar-Green survey, we find evidence for a dependence of radio luminosity on accretion rate relati ve to the Eddington limit, L/L-Edd, as well as on M-bh, consistent with the well-known radio-optical correlation for radio-loud quasars. We therefore suggest a new scheme to "unify" radio-loud and radio-quiet objects in which the radio luminosity scales proportional to M-bh(1.9+/-0.2) (L/L-Edd)(1.0) for L/L-Edd similar to0.1, with an apparently weaker accretion rate depend ence at low L/L-Edd. The scatter about this relation is +/-1.1 dex and may well hide significant contributions from other physical effects, such as th e black hole spin and radio source environment.