The cosmological evolution of quasar black-hole masses
| dc.creator | McLure, R. J. | |
| dc.creator | Dunlop, J. S. | |
| dc.date | 2003-10-09 | |
| dc.date | 2004-05-19 | |
| dc.date.accessioned | 2026-07-07T10:47:43Z | |
| dc.date.available | 2026-07-07T10:47:43Z | |
| dc.description | Virial black-hole mass estimates are presented for 12698 quasars in the redshift interval 0.1<z<2.1, based on modelling of spectra from the Sloan Digital Sky Survey (SDSS) first data release. The black-hole masses of the SDSS quasars are found to lie between $\simeq10^{7}\Msun$ and an upper limit of $\simeq 3\times 10^{9}\Msun$, entirely consistent with the largest black-hole masses found to date in the local Universe. The estimated Eddington ratios of the broad-line quasars (FWHM\geq 2000 kms^{-1}) show a clear upper boundary at $L_{bol}/L_{Edd}\simeq 1$, suggesting that the Eddington luminosity is still a relevant physical limit to the accretion rate of luminous broad-line quasars at $z\leq 2$. By combining the black-hole mass distribution of the SDSS quasars with the 2dF quasar luminosity function, the number density of active black holes at $z\simeq 2$ is estimated as a function of mass. In addition, we independently estimate the local black-hole mass function for early-types using the $M_{bh}-σ$ and $M_{bh}-L_{bulge}$ correlations. Based on the SDSS velocity dispersion function and the 2MASS $K-$band luminosity function, both estimates are found to be consistent at the high-mass end ($M_{bh}\geq 10^{8}\Msun$). By comparing the estimated number density of active black holes at $z\simeq 2$ with the local mass density of dormant black holes, we set lower limits on the quasar lifetimes and find that the majority of black holes with mass $\geq 10^{8.5}\Msun$ are in place by $\simeq 2$. | |
| dc.description | 15 pages, 10 figures, revised version, accepted for publication by MNRAS | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0310267 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0310267 | |
| dc.identifier | Mon.Not.Roy.Astron.Soc.352:1390,2004 | |
| dc.identifier | doi:10.1111/j.1365-2966.2004.08034.x | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/183629 | |
| dc.subject | Astrophysics | |
| dc.title | The cosmological evolution of quasar black-hole masses | |
| dc.type | text |