The Luminosity Function of the EGRET Gamma‐Ray Blazars

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Abstract
We examine the properties of the gamma-ray active galactic nuclei (AGNs) detected by EGRET. We calculate the evolution and luminosity function of the gamma-ray-loud AGNs, and we estimate the contribution this source class makes to the diffuse extragalactic gamma-ray background. These calculations are based on a sample of EGRET observations complete through the Compton Gamma-Ray Observatory observing Cycle 4. We use the Ve/Va test to measure the luminosity evolution and the nonparametric c--method to estimate the de-evolved luminosity function. We also consider inclusion in the 1 Jy radio catalog of Kühr et al. (1981) as an additional criterion to help guard against selection effects resulting from incomplete redshift determinations for AGNs in our sample. Our results include evidence for a low-luminosity cutoff in the gamma-ray AGN luminosity distribution, a more precise estimate of the contribution of these objects to the diffuse extragalactic gamma-ray background, and constraints on the gamma-ray production mechanism based upon the statistics implied by relativistic beaming of the emission. We discuss the implications of these findings for models of AGN unification and the relationship of gamma-ray to radio emission.