出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：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 luminos- ity 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 nu- clei, 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 dis- cover a few blazars up to z ∼ 6 in the entire sky during its 5–year survey. We also discuss how such high-redshift blazar candidates may be efficiently selected in future Fermi data. We further discuss that the GeV gamma-ray spectra of such high-redshift blazars would be a probe of the early cosmic star formation history.
