THE IMPORTANCE OF BROAD EMISSION LINE WIDTHS IN SINGLE-EPOCH BLACK HOLE MASS ESTIMATES
- Jet Propulsion Laboratory, California Institute of Technology, MS 169-530, 4800 Oak Grove Dr., Pasadena, CA 91109 (United States)
- Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States)
Estimates of the mass of super-massive black holes (BHs) in distant active galactic nuclei (AGNs) can be obtained efficiently only through single-epoch (SE) spectra, using a combination of their broad emission line widths and continuum luminosities. Yet the reliability and accuracy of the method and the resulting mass estimates, M{sub BH}, remain uncertain. A recent study by Croom using a sample of Sloan Digital Sky Survey, 2dF QSO Redshift Survey, and 2dF-SDSS LRG and QSO Survey quasars suggests that line widths contribute little information about the BH mass in these SE estimates and can be replaced by a constant value without significant loss of accuracy. In this Letter, we use a sample of nearby reverberation-mapped AGNs to show that this conclusion is not universally applicable. We use the bulge luminosity (L{sub Bulge}) of these local objects to test how well the known M{sub BH}-L{sub Bulge} correlation is recovered when using randomly assigned line widths instead of the measured ones to estimate M{sub BH}. We find that line widths provide significant information about M{sub BH}, and that for this sample, the line width information is just as significant as that provided by the continuum luminosities. We discuss the effects of observational biases upon the analysis of Croom and suggest that the results can probably be explained as a bias of flux-limited, shallow quasar samples.
- OSTI ID:
- 22047724
- Journal Information:
- Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 753; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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