Blazars and the cosmic gamma-ray background in the Fermi and CTA era

摘要

We present a new model of the blazar gamma-ray luminosity function (GLF), which is consistent with the EGRET blazar data. The unified sequence of blazar spectral energy distribution (SED) is taken into account to make a non-trivial prediction for the extragalactic gamma-ray background (EGRB) spectrum. We then try to explain the EGRB data by the two active galactic nucleus (AGN) populations: one is blazars, and the other is non-blazar AGNs that are responsible for the EGRB in the MeV band. We find that the predicted EGRB spectrum is in agreement with a wide range of the observed data from X-ray to GeV. These results indicate that AGNs including blazars are the primary source of EGRB. Especially, our model predicts ~1000 blazars will be detected down to 2 × 10~(-9) photons cm~(-2)s~(-1) (>100 MeV) by Fermi observations, which is considerably smaller than most of previous studies. Furthermore, we also make some predictions for future TeV blazar survey by next generation of imaging atmospheric Cherenkov telescopes. We found that it is difficult to find TeV blazars by blind sky survey.