Source population synthesis and the Galactic diffuse gamma-ray emission

Abstract

Population synthesis is used to study the contribution from undetected sources to the Galactic ridge emission measured by EGRET. Synthesized source counts are compared with the 3rd EGRET catalogue at low and high latitudes. For pulsar-like populations, 5-10% of the emission >100 MeV comes from sources below the EGRET threshold. A steeper luminosity function can increase this to 20% without violating EGRET source statistics. Less luminous populations can produce much higher values without being detected. Since the unresolved source spectrum is different from the interstellar spectrum, it could provide an explanation of the observed MeV and GeV excesses above the predictions, and we give an explicit example of how this could work.

Astrophysics and Space Science, in press. (Proceedings of Conference 'The multi-messenger approach to high-energy gamma-ray sources', Barcelona, 2006). Minor changes for accepted version, updated references

References in corpus (1)

• Gamma-ray continuum emission from the inner Galactic region as observed with INTEGRAL/SPI

Cited by in corpus (5)

• Fermi Large Area Telescope Bright Gamma-ray Source List
• Pre-launch estimates for GLAST sensitivity to Dark Matter annihilation signals
• Constraints on the TeV source population and its contribution to the galactic diffuse TeV emission
• Unidentified EGRET Sources and the Extragalactic Gamma-Ray Background
• High-Energy Cosmology: gamma rays and neutrinos from beyond the galaxy