Large-Scale Anisotropy of EGRET Gamma Ray Sources
Abstract
In the course of its operation, the EGRET experiment detected high-energy gamma ray sources at energies above 100 MeV over the whole sky. In this communication, we search for large-scale anisotropy patterns among the catalogued EGRET sources using an expansion in spherical harmonics, accounting for EGRET's highly non-uniform exposure. We find significant excess in the quadrupole and octopole moments. This is consistent with the hypothesis that, in addition to the galactic plane, a second mid-latitude (5^{\circ} < |b| < 30^{\circ}) population, perhaps associated with the Gould belt, contributes to the gamma ray flux above 100 MeV.
Cite
@article{arxiv.astro-ph/0506598,
title = {Large-Scale Anisotropy of EGRET Gamma Ray Sources},
author = {Luis Anchordoqui and Thomas McCauley and Thomas Paul and Olaf Reimer and Diego F. Torres},
journal= {arXiv preprint arXiv:astro-ph/0506598},
year = {2007}
}
Comments
To be published in Proceedings of ICRC 2005, 29th International Cosmic Ray Conference, Pune, India. http://www.tifr.res.in/icrc2005/