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Title: Relativistic redshifts in quasar broad lines

The broad emission lines commonly seen in quasar spectra have velocity widths of a few percent 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 Hβ line in the quasar rest frame (determined from the core component of the [O III] line) for over 20,000 quasars from the Sloan Digital Sky Survey Data Release 7 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°, consistent with simple active galactic nucleus 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.
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. Institute for Advanced Study, Princeton, NJ 08540 (United States)
  2. Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
  3. Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)
  4. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
Publication Date:
OSTI Identifier:
22370485
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 794; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; APPROXIMATIONS; CATALOGS; EMISSION; GALAXY NUCLEI; INCLINATION; LINE WIDTHS; QUASARS; RANDOMNESS; RED SHIFT; RELATIVISTIC RANGE; SPECTRA; VELOCITY; VISIBLE RADIATION