Faint Active Galactic Nuclei and the Ionizing Background

Abstract

We determine the evolution of the faint, high-redshift, optical luminosity function (LF) of active galactic nuclei (AGNs) implied by several observationally motivated models of the ionizing background from 3 ~0.2. Conversely, the lower flux decrement-derived background requires a smaller number of ionizing sources, and faint AGN counts are consistent with this estimate only if there is a limited stellar contribution, fesc ~107 yr for favored cases.