Implications of Plasma Beam Instabilities for the Statistics of the
  Fermi Hard Gamma-ray Blazars and the Origin of the Extragalactic Gamma-Ray
  Background
  Fermi has been instrumental in constraining the luminosity function and
redshift evolution of gamma-ray bright blazars. This includes limits upon the
spectrum and anisotropy of the extragalactic gamma-ray background (EGRB),
redshift distribution of nearby Fermi active galactic nuclei (AGN), and the
construction of a log(N)-log(S) relation. Based upon these, it has been argued
that the evolution of the gamma-ray bright blazar population must be much less
dramatic than that of other AGN. However, critical to such claims is the
assumption that inverse Compton cascades reprocess emission above a TeV into
the Fermi energy range, substantially enhancing the strength of the observed
limits. Here we demonstrate that in the absence of such a process, due, e.g.,
to the presence of virulent plasma beam instabilities that preempt the cascade,
a population of TeV-bright blazars that evolve similarly to quasars is
consistent with the population of hard gamma-ray blazars observed by Fermi.
Specifically, we show that a simple model for the properties and luminosity
function is simultaneously able to reproduce their log(N)-log(S) relation,
local redshift distribution, and contribution to the EGRB and its anisotropy
without any free parameters. Insofar the naturalness of a picture in which the
hard gamma-ray blazar population exhibits the strong redshift evolution
observed in other tracers of the cosmological history of accretion onto halos
is desirable, this lends support for the absence of the inverse Compton
cascades and the existence of the beam plasma instabilities.
