Searching for the most distant blazars with the Fermi Gamma-ray Space
  Telescope
  We investigate the prospects for discovering blazars at very high-redshifts
(z>3-6) with the Fermi Gamma-Ray Space Telescope (Fermi), employing a model for
the evolving gamma-ray luminosity function (GLF) of the blazar population. Our
previous GLF model is used as a basis, which features luminosity-dependent
density evolution implied from X-ray data on active galactic nuclei, as well as
the blazar sequence paradigm for their spectral energy distribution, and which
is consistent with EGRET and current Fermi observations of blazars.Here we
augment the high-redshift evolution of this model by utilizing the luminosity
function of quasars from the Sloan Digital Sky Survey (SDSS), which is
well-constrained up to z~5. We find that Fermi may discover a few blazars up to
z~6 in the entire sky during its 5-year survey. We further discuss how such
high-redshift blazar candidates may be efficiently selected in future Fermi
data.
