We have undertaken a new ground-based monitoring campaign to improve the estimates of the mass of the central black hole in NGC 4151. We measure the lag time of the broad H beta line response compared to the optical continuum at 5100 A and find a lag of 6.6 (+1.1/-0.8) days. We combine our data with the recent reanalysis of UV emission lines by Metzroth et al. to calculate a weighted mean of the black hole mass, M_BH = 4.57 (+0.57/-0.47) x 10^7 M_sun. The absolute calibration of the black hole mass is based on normalization of the AGN black hole mass - stellar velocity dispersion (M_BH - sigma_*) relationship to that of quiescent galaxies by Onken et al. The scatter in the M_BH - sigma_* relationship suggests that reverberation-mapping based mass measurements are typically uncertain by a factor of 3-4.
@article{arxiv.astro-ph/0607085,
title = {A Reverberation-Based Mass for the Central Black Hole in NGC 4151},
author = {Misty C. Bentz and Kelly D. Denney and Edward M. Cackett and Matthias Dietrich and Jeffrey K. J. Fogel and Himel Ghosh and Keith Horne and Charles Kuehn and Takeo Minezaki and Christopher A. Onken and Bradley M. Peterson and Richard W. Pogge and Vladimir I. Pronik and Douglas O. Richstone and Sergey G. Sergeev and Marianne Vestergaard and Matthew G. Walker and Yuzuru Yoshii},
journal= {arXiv preprint arXiv:astro-ph/0607085},
year = {2008}
}
Comments
17 pages, 3 tables, 3 figures, accepted for publication in ApJ