The disk-jet symbiosis is a fundamental problem in our understanding of the Active Galactic Nuclei （AGN）. We explore the relation between the Doppler factors d of the jet of blazars and their broad line region lumin...The disk-jet symbiosis is a fundamental problem in our understanding of the Active Galactic Nuclei （AGN）. We explore the relation between the Doppler factors d of the jet of blazars and their broad line region luminosity LBLR. Since different methods measuring δ might differ substantially, we use data obtained from 3 independent methods and compile 3 samples of sources for each of them, respectively. Two samples consist of blazars, that is, Flat Spectrum Radio Quasars （FSRQs） and BL Lacertae objects （BL Lacs）, and the other consists of BL Lacs. dis one of the most important jet properties and LBLR is thought to be the proxy of the accretion power. Correlation analysis to these samples shows that there exists a significant correlation between δ and LBLR, which supports the idea that the jet powering process is closely linked with the accretion process and provides new evidence for disk-jet connection. Furthermore, the results are consistent with the idea that the Blandford-Znajek mechanism is sufficient for BL Lacs and a hybrid model is needed for FSRQs.展开更多
Radiative efficiency is an important physical parameter that describes the fraction of accretion material converted to radiative energy for accretion onto massive black holes （MBHs）. With the simplest Sottan argumen...Radiative efficiency is an important physical parameter that describes the fraction of accretion material converted to radiative energy for accretion onto massive black holes （MBHs）. With the simplest Sottan argument, the radiative efficiency of MBHs can be estimated by matching the mass density of MBHs in the local universe to the accreted mass density by MBHs during AGN/QSO phases. In this paper, we estimate the local MBH mass density through a combination of various determinations of the correlations between the masses of MBHs and the properties of MBH host galaxies, with the distribution functions of those galaxy properties. We also estimate the total energy density radiated by AGNs and QSOs by using various AGN/QSO X-ray luminosity functions in the literature. We then obtain several hundred estimates of the mean radiative efficiency of AGNs/QSOs. Under the assumption that those estimates are independent of each other and free of systematic effects, we apply the median statistics as described by Gott et al. and find the mean radiative efficiency of AGNs/QSOs is ε = 0.105＋0.006- 0.008, which is consistent with the canonical value -0.1. Considering that about 20% Compton-thick objects may be missed from current available X-ray surveys, the true mean radiative efficiency may be actually -0.12.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.10973034,10978019,11043002)the State Key Development Program for Basic Research of China(Grant No. 2009CB824800)the Provincial Natural Science Foundation of Yunnan (Grant No.09401145,1012456)
文摘The disk-jet symbiosis is a fundamental problem in our understanding of the Active Galactic Nuclei （AGN）. We explore the relation between the Doppler factors d of the jet of blazars and their broad line region luminosity LBLR. Since different methods measuring δ might differ substantially, we use data obtained from 3 independent methods and compile 3 samples of sources for each of them, respectively. Two samples consist of blazars, that is, Flat Spectrum Radio Quasars （FSRQs） and BL Lacertae objects （BL Lacs）, and the other consists of BL Lacs. dis one of the most important jet properties and LBLR is thought to be the proxy of the accretion power. Correlation analysis to these samples shows that there exists a significant correlation between δ and LBLR, which supports the idea that the jet powering process is closely linked with the accretion process and provides new evidence for disk-jet connection. Furthermore, the results are consistent with the idea that the Blandford-Znajek mechanism is sufficient for BL Lacs and a hybrid model is needed for FSRQs.
基金the National Key Program for Science and Technology Research and Development(Grant No.2016YFA0400704)the National Natural Science Foundation of China(Grant Nos.11373031,and11390372)the Strategic Priority Program of the Chinese Academy of Sciences(Grant No.XDB 23040100)
文摘Radiative efficiency is an important physical parameter that describes the fraction of accretion material converted to radiative energy for accretion onto massive black holes （MBHs）. With the simplest Sottan argument, the radiative efficiency of MBHs can be estimated by matching the mass density of MBHs in the local universe to the accreted mass density by MBHs during AGN/QSO phases. In this paper, we estimate the local MBH mass density through a combination of various determinations of the correlations between the masses of MBHs and the properties of MBH host galaxies, with the distribution functions of those galaxy properties. We also estimate the total energy density radiated by AGNs and QSOs by using various AGN/QSO X-ray luminosity functions in the literature. We then obtain several hundred estimates of the mean radiative efficiency of AGNs/QSOs. Under the assumption that those estimates are independent of each other and free of systematic effects, we apply the median statistics as described by Gott et al. and find the mean radiative efficiency of AGNs/QSOs is ε = 0.105＋0.006- 0.008, which is consistent with the canonical value -0.1. Considering that about 20% Compton-thick objects may be missed from current available X-ray surveys, the true mean radiative efficiency may be actually -0.12.
