The Contribution from Radio Quiet Quasars to γ-ray Background

摘要

The EGRET observations have confirmed and proposed the newisotropically distributed γ-ray background, but the known objects radiating γrays can not supply so much radiation. Meanwhile, EGRET also reveals a pop-ulation of γ-ray sources with no radio counterparts which are isotropically dis-tributed in the sky, indicating their possible cosmological origins. Wang et al.[13]proposed a new γ-ray radiation process driven by the radiation feedback of AGNs.The energy of the radiation peaks around 1 GeV-0.1 TeV with the typical lu-minosity of 10~(42)-10~(43)ergs . s-1.This kind of radiation process in the radioquiet quasars make them the potential γ-ray radiation sources as well as thecontributors to the γ-ray background. We consider two cases in which the seedphotons in the inverse-Compton processes are from the accretion disks of quasarsand cosmic microwave background (CMB), respectively. We find that the formercontributes 78%-92% of the background radiation around 1 GeV, while the con-tribution from the latter is negligible. The radio quiet quasars are highly likelyto become the objects which contribute the most energy to the γ-ray backgroundaround 1 GeV.