Relativistic Beaming Effect in Fermi Blazars

Abstract

The most identified sources observed by Fermi/LAT are blazars, based on which we can investigate the emission mechanisms and beaming effect in the γ-ray bands for blazars. Here, we used the compiled around 450 Fermi blazars with the available X-ray observations to estimate their Doppler factors and compared them with the integral γ-ray luminosity in the range of 1–100 GeV. It is interesting that the integral γ-ray luminosity is closely correlated with the estimated Doppler factor, $\text {log}\, \nu _{\gamma } {\mathit {L}}_{\nu _{\gamma }} = (2.95\,\pm \,0.09) \text {log}\; \delta \,+\,43.59\,\pm \, 0.08$ for the whole sample. When the dependence of the correlation between them and the X-ray luminosity is removed, the correlation is still strong, which suggests that the γ-ray emissions are strongly beamed.