Calibration of the virial factor f in SMBHs

Using a compiled sample of 34 broad-line active galactic nuclei (AGNs) with measured H{beta} time lags from the reverberation mapping (RM) method and measured bulge stellar velocity dispersions {sigma}_*_, we calculate the virial factor f by assuming that the RM AGNs intrinsically obey the same M_BH_-{sigma}_*_ relation as quiescent galaxies, where M_BH_ is the mass of the supermassive black hole (SMBH). Considering four tracers of the velocity of the broad-line regions (BLRs), i.e. the H{beta} line width or line dispersion from the mean or rms spectrum, there are four kinds of the factor f.

Using the H{beta} full width at half-maximum (FWHM) to trace the BLRs velocity, we find significant correlations between the factor f and some observational parameters, e.g. FWHM, the line dispersion. Using the line dispersion to trace the BLRs velocity, these relations disappear or become weaker. It implies the effect of inclination in BLRs geometry.