On the masses of black-holes in radio-loud quasars

The central black-hole masses of 85 radio-loud quasars are estimated using available data of $H_{\beta}$ line-width and optical continuum luminosity. The vast majority of the quasars in this sample have black-hole masses larger than $10^{8} M_{\odot}$, while a few quasars may contain relatively smaller black-holes. It is found that the radio-loudness decreases with the black-hole mass.