Do quiescent and active galaxies have different M BH-σ * relations?

Abstract

To investigate the validity of the assumption that quiescent galaxies and active galaxies follow the same black hole mass (MBH)-stellar velocity dispersion (σ) relation, as required for the calibration of MBH estimators for broad line active galactic nuclei (AGNs), we determine and compare the MBH-σ * relations, respectively, for quiescent and active galaxies. For the quiescent galaxy sample, composed of 72 dynamical MBH measurements, we update σ * for 28 galaxies using homogeneous H-band measurements that are corrected for galaxy rotation. For active galaxies, we collect 25 reverberation-mapped AGNs and improve σ * measurement for two objects. Combining the two samples, we determine the virial factor f, first by scaling the active galaxy sample to the MBH-σ * relation of quiescent galaxies, and second by simultaneously fitting the quiescent and active galaxy samples, as and , respectively. The MBH-σ * relation of active galaxies appears to be shallower than that of quiescent galaxies. However, the discrepancy is caused by a difference in the accessible MBH distribution at given σ *, primarily due to the difficulty of measuring reliable stellar velocity dispersion for the host galaxies of luminous AGNs. Accounting for the selection effects, we find that active and quiescent galaxies are consistent with following intrinsically the same M BH-σ * relation. © 2013. The American Astronomical Society. All rights reserved.