THE LICK AGN MONITORING PROJECT: THE<i>M</i>_BH-σ_*RELATION FOR REVERBERATION-MAPPED ACTIVE GALAXIES

(Abridged) To investigate the black hole mass (MBH) vs. stellar velocity\ndispersion relation of active galaxies, we measured the velocity dispersions of\na sample of local Seyfert 1 galaxies, for which we have recently determined MBH\nusing reverberation mapping. For most objects, velocity dispersions were\nmeasured from high S/N ratio optical spectra centered on the Ca II triplet\nregion (~8500 A), obtained at the Keck, Palomar, and Lick Observatories. For\ntwo objects, in which the Ca II triplet region was contaminated by nuclear\nemission, the measurement was based on high-quality H-band spectra obtained\nwith the OSIRIS at the Keck-II Telescope. Combining our new measurements with\ndata from the literature, we assemble a sample of 24 active galaxies with\nstellar velocity dispersions and reverberation-based MBH measurements in the\nrange of black hole mass 10^6&lt;MBH/M_sun&lt;10^9. We use this sample to obtain\nreverberation mapping constraints on the slope and intrinsic scatter of the\nM-sigma relation of active galaxies. Assuming a constant virial coefficient f\nfor the reverberation mapping black hole masses, we find a slope b=3.55+-0.60\nand the intrinsic scatter sigma_int=0.43+-0.08 dex in the relation log\n(MBH/M_sun) = a + b log (sigma/200 km/s), which are consistent with those found\nfor quiescent galaxies. We derive an updated value of the virial coefficient f\nby finding the value which places the reverberation masses in best agreement\nwith the M-sigma relation of quiescent galaxies; using the quiescent M-sigma\nrelation determined by Gultekin et al. we find log f=0.72^{+0.09-0.10} with an\nintrinsic scatter of 0.44+-0.07 dex. The uncertainty of the virial coefficient\nremains one of the main sources of the uncertainty in black hole mass\ndeterminations using reverberation mapping, and therefore also in single-epoch\nspectroscopic estimates of MBH in active galaxies.\n