On the masses of black holes in radio-loud quasars

The central black-hole masses of a sample of radio-loud quasars are estimated by using the data of Hβ line-width and the optical continuum luminosity. The vast majority of the quasars in this sample have black-hole masses larger than 10⁸ M_, while a few quasars may contain relatively smaller black-holes. We found a significant anti-correlation between the radio-loudness and the central black-hole mass. It might imply that the jet formation is governed by the black-hole mass.