Title: Probing Early AGN Evolution by Finding the Highest Redshift Blazars 
with the Fermi Gamma-Ray Telescope
Author(s): Yoshiyuki Inoue, Susumu Inoue, &  Tomonori Totani
Abstract: The universe above redshift 6.5 is still not well understood 
even with current large telescopes. Since the GeV gamma-rays attenuate with
UV photons, gamma-ray spectra of high-z blazars could be a new
key to understand the reionization epoch. We examine the possibility that 
Fermi gamma-ray space
telescope has a capability to reveal high-z universe with its all sky
monitoring and high sensitivity observation in gamma-ray band. Inoue &
Totani 2008 has recently presented a new blazar gamma-ray luminosity
function (GLF) which is based on recent active galactic nucleus (AGN) X-ray
luminosity function and also takes into account blazar sequence SED.
However, the cosmological blazar density in this model is only
constrained from EGRET blazars and X-ray AGNs whose redshift are less
than ~3. Therefore we modified IT08 blazar GLF model with
cosmological semianalytical AGN evolution models and recent Sloan
digital sky survey AGN data whose highest redshift is ~6.5. With
these further constraints on high-z blazar evolution to IT08 GLF, we
discuss how high-z blazars Fermi will detect . We also discuss whether 
current optical/infrared telescopes such as Subaru would be able to 
determine those spectroscopic redshifts.