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

Bhattacharya, Debbijoy and Sreekumar, Parameswaran (2009) Contribution from normal and starburst galaxies to the extragalactic gamma-ray background (EGRB). In: Research in astronomy and astrophysics, 9 (5). pp. 509-519.

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Abstract

The extragalactic diffuse emission at gamma-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 gamma-ray background emission from normal galaxies and starburst galaxies. gamma-ray emission from normal galaxies is primarily coming from cosmic-ray interactions with interstellar matter and radiation (similar to 90%) along with a small contribution from discrete point sources (similar to 10%). Starburst galaxies are expected to have enhanced supernovae activity which leads to higher cosmic-ray densities, making starburst galaxies sufficiently luminous at gamma-ray energies to be detected by the current gamma-ray mission(Fermi Gamma-ray Space Telescope).

Item Type:	Journal Article
Publication:	Research in astronomy and astrophysics
Publisher:	Institute of Physics
Additional Information:	Copyright for this article belongs toInstitute of Physics.
Keywords:	galaxy: general; galaxies: luminosity function; galaxies: starburst; gamma-rays: observations.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	02 Jul 2009 13:40
Last Modified:	19 Sep 2010 05:34
URI:	http://eprints.iisc.ac.in/id/eprint/20834

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