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The Masses of Quasars and AGN: Correlating the Accretion-Disk and the Emission-Line Methods

Published online by Cambridge University Press:  07 August 2017

Amri Wandel
Amri Wandel*
Affiliation:
Center of Space Science and Astrophysics, Stanford University, ERL, Stanford, CA 94305, USA

Abstract

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The UV continuum spectrum is used to extract the mass (and accretion rate) of quasars and AGN, assuming the UV is dominated by the emission from a thin accretion disk. This is done by fitting the observed luminosity and spectral slope in the UV by an accretion disk mode, giving the accretion parameters (black hole mass and accretion rate). An independent estimate of the mass is obtained using the emission-line method, which assumes that the velocity dispersion of the broad emission-line s is induced by the gravitational potential of the central compact object. For a sample of 36 quasars and Seyfert 1 galaxies, for which both data, the UV spectrum and the Hβ line width are available, the masses calculated with the two independent methods are in good agreement (within a factor of 2 for 75% of the sample) and highly correlated. Over three orders of magnitude in luminosity, the mass is found to increase less than linearely with luminosity, being in the range 108 < M < 1010M⊙, with L(1450A)/LEdd ranging from 0.001 for Seyferts to 0.03 for bright quasars.

Type
Part 1: Surveys, Luminosity Functions, and Evolution
Information
Symposium - International Astronomical Union , Volume 134: Active Galactic Nuclei , 1989 , pp. 62 - 64
Copyright
Copyright © Kluwer 1989 

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