Accretion rates and the accretion efficiency in AGNs

We used the standard geometrical-thin accretion theory to obtain the accretion rates in Seyfert 1 galaxies and quasars. Combining the accretion rates with the bolometric luminosity, we obtained the accretion efficiency. We found that most Seyfert 1 galaxies and radio-quiet quasars have lower accretion efficiencies, while most radio-loud quasars possess higher accretion efficiencies. This finding further implies that most of the radio-loud quasars possess Kerr black holes, while Seyfert 1 galaxies and radio-quiet quasars may not possess Kerr black holes. Considering the difference in the accretion efficiency, we found that there is a strong correlation between the accretion rate in units of the Eddington accretion rate and the width of the Hbeta emission line, and that most AGNs are not accreting at super-Eddington rates.