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 redshifl z 〈 0.83 in Data Release 3 of the Sloan Digital Sky Survey （SDSS）. The sample consists of 3772 quasars with better models of the H/4 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 Hβline, and the host stellar velocity dispersion （σ＊） is traced by the core [O Ⅲ] gaseous velocity dispersion. The radio luminosity and radio loudness are derived from the FIRST catalog. Our results are as follows： （1） For radio-quiet quasars, we confirm that there is no obvious deviation from the MBH-σ＊ relation defined for inactive galaxies when the uncertainties in ~IBH and the luminosity bias are concerned. （2） We find that the radio-loud quasars deviate more from the MBH-σ＊ relation than do the radio-quiet quasars. This deviation is only partly due to a possible cosmological evolution of the MBH-σ＊ relation and the luminosity bias. （3） The radio luminosity is proportional to MBH1.28＋0.23-0.16（LBol/LEdd） ^1.29＋0.31-0.24 for radio-quiet quasars and to -MBH3.10＋0.60-0.70（LBol/LEdd）^4.18＋1.40-1.10 - for radio-loud quasars. The weaker dependence of the radio luminosity on the mass and the Eddington ratio for radio-loud quasars shows that other physical effects would account for their radio luminosities, such as the spin of the black hole.

Relation between the “Double-Hump” Behavior in the Radio Band and the Broad-Line Luminosity for Blazars

The physics behind the spectral energy distribution （SED） of blazars remains open. We assembled 36 blazars to tackle the factors that control their SED. Now, many blazar spectra have the ＂double hump＂ feature in the radio and far-IR frequencies. For these a parameter, △, is created to characterize the behavior of the SED. We found a significant correlation between the broad-line luminosity （LBLR） and △. Because L BLR is an indicator of the accreting power of the source in blazars, we derived a linear correlation, △ oc M1/3.18, which suggests that the SED of blazars may depend on the accretion rate, like that of BL Lac objects. We also found a significant correlation between m and △ for a sample of 11 blazars （out of one of 36） with available black hole masses. This implies the Eddington accretion ratio may influence the shape of the SED of blazars.