Black hole mass estimates using gravitational redshift of broad emission lines in active galactic nuclei

Abstract

Here we present results of black hole mass estimates using gravitational redshift for a sample of 285 type 1 Active Galactic Nuclei (AGN) selected from the Sloan Digital Sky Survey database. The shifts are measured as a difference between the centroids at 5% and 95% of the Hβ and Mg II broad line intensities. Obtained masses have been compared with ones estimated from wide accepted virial method (using widths of Hβ and Mg II broad lines). We discuss the possibility to use the gravitational redshift for black hole mass estimations in AGN and validity of virialization assumption in the AGN broad lines.