Can the extragalactic gamma-ray background be explained by AGN?

Tanja M. Kneiske, Karl Mannheim, Lukasz Stawarz, Jun Kataoka

Research output: Contribution to journalConference articlepeer-review


Very high energy gamma-rays from blazars traversing cosmological distances through the meta-galactic radiation field can convert into electron-positron pairs in photon-photon collisions. The converted gamma-rays initiate electromagnetic cascades driven by inverse-Compton scattering with microwave background photons. Using a model for the time-dependent meta-galactic radiation field consistent with currently available far-infrared to optical data, the cascade contributions by faint, unresolved sources like blazars and FRI galaxies have been calculated. We come to the conclusion that depending on what is known so far about AGN, they are not able to produce the total extragalactic flux detected by EGRET. A test for the model will be the upcoming observations with FERMI. It would also be helpful to detect a signal above 100 GeV where the gamma-ray flux declines to 10-7GeV sr-1 cm-2 s-1.

Original languageEnglish
Pages (from-to)510-513
Number of pages4
JournalAIP Conference Proceedings
Publication statusPublished - 2009
Externally publishedYes
Event4th International Meeting on High Energy Gamma-Ray Astronomy - Heidelberg, Germany
Duration: 2008 Jul 72008 Jul 11


  • Background radiations
  • Gamma-ray sources

ASJC Scopus subject areas

  • General Physics and Astronomy


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