CORRELATIONS AMONG THE JET, ACCRETION DISK, AND BROAD-LINE REGION OF FLAT SPECTRUM RADIO QUASARS

Abstract

On the basis of the spectral energy distribution fits and emission line fluxes of 18 GeV flat spectrum radio quasars (FSRQs), we calculate their jet power (P-jet), disk luminosity (L-disk), and broad-line region luminosity (L-BLR). No correlation between P-jet with either L-disk or L-BLR is found, but L-BLR is strongly correlated with L-disk. On average, the broad-line region (BLR) covering factors of GeV-FSRQs in our sample are smaller than those of large samples of quasars. P-jet of some GeV-FSRQs are higher than their L-disk, but all of them are lower than the accretion power of black holes (BHs), which is estimated by (M) over dotc(2) = L-disk/0.1, indicating that the total accretion power of BHs is sufficient to drive the jets in these sources; however,. lack of correlation between L-disk and P-jet of the GeV-FSRQs may suggest that their jets are launched by the Blandford-Znajek process via extracting the rotational energy of BHs. Using the L-BLR-L-disk relation of the GeV-FSRQs, we estimate L-disk of a BL Lac sample with their L-BLR. A comparison of L-BLR and the Eddington ratio (L-disk/L-Edd) among BL Lacs, very radio-loud NLS1 galaxies, and FSRQs is also presented. It is found that along with the BL Lac-NLS1-FSRQ sequence L-BLR and L-disk/L-Edd increase, which may correspond to the change of the accretion disk structure and the transformation of the dominant mechanism for jet launching. This is also consistent with the division of blazar parent populations, i.e., low/high-excitation radio galaxies.