Black Hole Masses of Weak Emission Line Quasars Based on the Continuum Fit Method

We studied optical-ultraviolet spectral energy distribution of 10 weak emission-line quasars (WLQs) that lie at redshifts z = 0.19 and 1.43 < z < 3.48. The theoretical models of their accretion disk continua are created based on the Novikov–Thorne equations. It allows us to estimate masses of their supermassive black holes ($M_{BH}$) and accretion rates. We determined the virial factor for WLQs and note its anticorrelation with the FWHM of the Hβ emission line $(f\propto {FWHM}^{\alpha },\alpha =-1.34\pm 0.37$). By comparison with the previously estimated BH masses, the underestimation of $M_{BH}$ is noticed with a mean factor of 4–5, which depends on the measured full width. We proposed a new formula to estimate $M_{BH}$ in WLQs based on their observed $FWHM$(Hβ) and luminosities at 5100 Å. In our opinion, WLQs are also normal quasars visible in a reactivation stage.