Central Engine And Radio Jets In Radio-loud Active Galactic Nuclei

In this thesis, we present the studies of the central engine and radio jets in radio-loud Active Galaxies Nuclei.The jet formation is thought to be closely connected with the mass of central supermassive black hole in Active Galactic Nuclei. The radio luminosity commonly used in investigating this issue is merely an indirect measure of the energy transported through the jets from the central engine, and severely Doppler boosted in core-dominated radio quasars. In this thesis, we investigate the relationship between the jet power and black hole mass, by estimating the jet power using extrapolated extended 151 MHz flux density from the VLA 5 GHz extended radio emission, for a sample of 146 radio loud quasars complied from literature. After removing the effect of relativistic beaming in the radio and optical emission, we find a significant intrinsic correlation between the jet power and black hole mass. It strongly implies that the jet power, so as jet formation, is closely connected with the black hole mass. To eliminate the beaming effect in the conventional radio loudness, we define a new radio loudness as the ratio of the radio extended luminosity to the optical luminosity estimated from the broad line luminosity. The strong anti-correlation between the conventional radio loudness and the black hole mass is not present with the new-defined radio loudness in radio-loud AGNs. In a tentatively combined sample of radio quiet with our radio loud quasars, the apparent gap around the conventional radio loudness R=10 is not prominent for the new-defined radio loudness. In this combined sample, we find a significant correlation between the black hole mass and new-defined radio loudness.In order to examine the relationship between the black hole mass M_bh and narrow line [O III] in radio-loud active galactic nuclei (AGNs), we study two effects which may cause the uncertainty of black hole mass estimates for radio-loud AGNs: the relativistic beaming effect on the observed optical continuum radiation and the orientation effect on broad emission line width. After correcting...