Contribution from normal and starburst galaxies to the extragalactic gamma-ray background (EGRB)

Debbijoy Bhattacharya, Parameswaran Sreekumar

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


The extragalactic diffuse emission at γ-ray energies has interesting cosmological implications since these photons suffer little or no attenuation during their propagation from the site of origin. The emission could originate from either truly diffuse processes or from unresolved point sources such as AGNs, normal galaxies and starburst galaxies. Here, we examine the unresolved point source origin of the extragalactic γ-ray background emission from normal galaxies and starburst galaxies. γ-ray emission from normal galaxies is primarily coming from cosmic-ray interactions with interstellar matter and radiation (∼90%) along with a small contribution from discrete point sources (∼10%). Starburst galaxies are expected to have enhanced supernovae activity which leads to higher cosmic-ray densities, making starburst galaxies sufficiently luminous at γ-ray energies to be detected by the current γ-ray mission (Fermi Gamma-ray Space Telescope).

Original languageEnglish
Pages (from-to)509-519
Number of pages11
JournalResearch in Astronomy and Astrophysics
Issue number5
Publication statusPublished - 2009

All Science Journal Classification (ASJC) codes

  • Space and Planetary Science
  • Astronomy and Astrophysics


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