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Evolution of the Luminosity Function of Quasars

Schmidt, Maarten (1986) Evolution of the Luminosity Function of Quasars. In: Structure and Evolution of Active Galactic Nuclei. Astrophysics and Space Science Library. No.121. Springer Netherlands , Dordrecht, pp. 3-10. ISBN 9789401085281.

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The luminosity function of quasars shows a strong dependence on redshift. We discuss alternate descriptions of this evolution. Density evolution is assumption-free if the density variation with red-shift is also allowed to be a function of absolute magnitude. Luminosity evolution and, in particular, pure luminosity evolution make a priori assumptions about the shape of the luminosity function. We illustrate the derivation of density evolution and its strong dependence on optical luminosity. We discuss work by Schmidt and Green (1985) on X-ray counts of quasars and the need for negative X-ray luminosity evolution to explain the counts and the low average redshift of X-ray quasars. As a consequence the quasar contribution to the 2 keV X-ray background is only around 8–13%. The evolution of active galactic nuclei of lower optical luminosity is tightly constrained by the observed X-ray background.

Item Type:Book Section
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Additional Information:© Springer Science+Business Media Dordrecht 1986. This research was supported in part by the National Science Foundation under grants AST-8111754 and AST-8314134.
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Series Name:Astrophysics and Space Science Library
Issue or Number:121
Record Number:CaltechAUTHORS:20200930-142646273
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105693
Deposited By: George Porter
Deposited On:01 Oct 2020 14:37
Last Modified:16 Nov 2021 18:45

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