Biases in Virial Black Hole Masses: An SDSS Perspective
| dc.creator | Shen, Yue | |
| dc.creator | Greene, Jenny E. | |
| dc.creator | Strauss, Michael A. | |
| dc.creator | Richards, Gordon T. | |
| dc.creator | Schneider, Donald P. | |
| dc.date | 2007-09-19 | |
| dc.date | 2008-01-03 | |
| dc.date.accessioned | 2026-07-07T11:37:20Z | |
| dc.date.available | 2026-07-07T11:37:20Z | |
| dc.description | We compile black hole (BH) masses for $\sim 60,000$ quasars in the redshift range $0.1 \lesssim z \lesssim 4.5$ included in the Fifth Data Release of the Sloan Digital Sky Survey (SDSS), using virial BH mass estimators based on the \hbeta, \MgII, and \CIV emission lines. We find that: (1) within our sample, the widths of the three lines follow log-normal distributions, with means and dispersions that do not depend strongly on luminosity or redshift;(2) the \MgII- and \hbeta-estimated BH masses are consistent with one another; and (3) the \CIV BH mass estimator may be more severely affected by a disk wind component than the \MgII and \hbeta estimators, giving a positive bias in mass correlated with the \CIV-\MgII blueshift. Most SDSS quasars have virial BH masses in the range $10^8-10^9 M_\odot$. There is a clear upper mass limit of $\sim 10^{10} M_\odot$ for active BHs at $z \gtrsim 2$, decreasing at lower redshifts. Making the reasonable assumptions that the underlying BH mass distribution decreases with mass and that the Eddington ratio distribution at fixed BH mass has non-zero width, we show that the measured virial BH mass distribution and Eddington ratio distribution are subject to Malmquist bias. A radio quasar subsample (with $1.5\lesssim z\lesssim 2.3$) has mean virial BH mass larger by $\sim 0.12$ dex than the whole sample. A broad absorption line (BAL) quasar subsample (with $1.7\lesssim z\lesssim 2.2$) has identical virial mass distribution as the nonBAL sample, with no mean offset. (Abridged) | |
| dc.description | Updated virial mass measurements; improved presentation of the MC simulation; added new discussion sections; conclusions unchanged. The full table1 is available at http://www.astro.princeton.edu/~yshen/BH_mass/datafile1.txt.tar.gz | |
| dc.identifier | https://arxiv.org/abs/0709.3098 | |
| dc.identifier | http://arxiv.org/abs/0709.3098 | |
| dc.identifier | Astrophys.J.680:169-190,2008 | |
| dc.identifier | doi:10.1086/587475 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/199173 | |
| dc.subject | Astrophysics | |
| dc.title | Biases in Virial Black Hole Masses: An SDSS Perspective | |
| dc.type | text |