  To investigate the validity of the assumption that quiescent galaxies and
active galaxies follow the same black hole mass - stellar velocity dispersion
relation, as required for the calibration of M_BH estimators for broad line
AGNs, we determine and compare the M-sigma relations, respectively, for
quiescent and active galaxies. For the quiescent galaxy sample, composed of 72
dynamical M_BH measurements, we update sigma 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 sigma measurement
for two objects . Combining the two samples, we determine the virial factor
$f$, first by scaling the active galaxy sample to the M-sigma relation of
quiescent galaxies, and second by simultaneously fitting the quiescent and
active galaxy samples, as f=5.1_{-1.1}^{+1.5} and f=5.9_{-1.5}^{+2.1},
respectively. The M-sigma relation of active galaxies appears to be shallower
than that of quiescent galaxies. However, the discrepancy is caused by a
difference in the accessible M_BH distribution at given sigma, 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-sigma relation.
