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Date and Time of the Query: 2019-06-16 T04:50:58 PDT
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For refcode 1989ApJ...343...54S:
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1989ApJ...343...54S TOWARD A CLASSIFICATION SCHEME FOR BROAD-LINE PROFILES IN ACTIVE GALACTIC NUCLEI JACK W. SULENTIC Department of Physics and Astronomy, University of Alabama, Tuscaloosa Received 1988 October 7; accepted 1989 January 6 ABSTRACT A study has been made of the broad-line H{beta} profile in quasars and Seyfert galaxies. All objects from the Palomar Bright Quasar Survey (PBQS; Schmidt and Green) catalog with published spectral scans have been included toward a goal of determining broad-line characteristics in a complete sample of active galactic nuclei (AGNs). The principal motivation for this study was to determine the range of spectral shifts exhibited by the broad lines relative to the narrow ones. We propose a simple classification scheme for broad-line H{beta} that would note the presence of systematic line shifts and line asymmetries. We investigate two samples of AGNs: (1) 25 objects from the PBQS and (2) a less well defined sample of 36 objects selected from various literature sources. Together these samples represent virtually all published spectra accurate enough to be reliably classified in our system. Combining the two samples (n = 61) we find: (a) only nine objects show symmetric and unshifted profiles; (b) a large number (15) of displaced profiles are symmetric, with redshifts twice as common as blue ones; (c) 35 objects show a measurable wavelength shift relative to the narrow-line region [O III] (from 120 to 1900 km s^-1^), with redshifts (20) slightly more common than blueshifts; (d) a shifted profile is very unlikely to show a blue asymmetry (red asymmetries are 8 times more common); and (e) 37 objects show an asymmetric profile with red (27) ones almost three times as common as blue. The distribution of wavelength centroids at all four measured profile heights (allowing for a few outliers) is displaced ~100 km s^-1^ toward the red. This can be interpreted as evidence for a small gravitational redshift in most AGNs. Subject headings: galaxies: Seyfert - line profiles - quasars
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