The radio luminosity, black hole mass and Eddington ratio for quasars from the Sloan Digital Sky Survey

We investigate the MBH−σ∗ relation for radio-loud quasars with redshift z < 0.83 in Data Release 3 of the Sloan Digital Sky Survey (SDSS). The sample consists of 3772 quasars with better model of Hβ and [O III] lines and available radio luminosity, including 306 radio-loud quasars, 3466 radio-quiet quasars with measured radio luminosity or upper-limit of radio luminosity (181 radio-quiet quasars with measured radio luminosity). The virial supermassive black hole mass (MBH ) is calculated from the broad Hβ line, the host stellar velocity dispersion (σ∗) is traced by the core [O III] gaseous velocity dispersion, and the radio luminosity and the radio loudness are derived from the FIRST catalog. Our results are follows: (1) For radio-quiet quasars, we confirm that there is no obvious deviation from the MBH − σ∗ relation defined in inactive galaxies when MBH uncertainties and luminosity bias are concerned. (2) We find that radio-loud quasars deviate much from the MBH−σ∗ relation respect to that for radio-quiet quasars. This deviation is only partly due to the possible cosmology evolution of the MBH − σ∗ relation and the luminosity bias. (3) The radio luminosity is proportional to M 1.28 −0.16 BH (LBol/LEdd) 1.29 −0.24 for radio-quiet quasars and M 3.10 −0.70 BH (LBol/LEdd) 4.18 −1.10 for radio-loud quasars. The weaker correlation of the radio luminosity dependence upon the mass and the Eddington ratio for radio-loud quasars shows that other physical effects would account for their radio luminosities, such as the black hole spin.