Relativistic redshifts in quasar broad lines

Abstract

The broad emission lines commonly seen in quasar spectra have velocity widths of a few per cent of the speed of light, so special- and general-relativistic effects have a significant influence on the line profile. We have determined the redshift of the broad H-beta line in the quasar rest frame (determined from the core component of the [OIII] line) for over 20,000 quasars from the Sloan Digital Sky Survey DR7 quasar catalog. The mean redshift as a function of line width is approximately consistent with the relativistic redshift that is expected if the line originates in a randomly oriented Keplerian disk that is obscured when the inclination of the disk to the line of sight exceeds ~30-45 degrees, consistent with simple AGN unification schemes. This result also implies that the net line-of-sight inflow/outflow velocities in the broad-line region are much less than the Keplerian velocity when averaged over a large sample of quasars with a given line width.

27 pages, 8 figures

References in corpus (4)

• A Catalog of Quasar Properties from SDSS DR7
• Biases in Virial Black Hole Masses: An SDSS Perspective
• A compendium of AGN inclinations with corresponding UV/optical continuum polarization measurements
• Evidence for Line Broadening by Electron Scattering in the Broad Line Region of NGC 4395

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• Measuring the Virial Factor in SDSS DR5 Quasars with Redshifted H$\beta$ and Fe ii Broad Emission Lines
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• Tests of General Relativity: A Review
• On Variation of Light Curves and Broad Emission Lines for Periodic QSOs from co-rotating Supermassive binary black holes in elliptical orbits