2005/06/24 by Luis Anchordoqui, Anchordoqui, Luis, Thomas McCauley +7
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0506598
To be published in Proceedings of ICRC 2005, 29th International Cosmic Ray Conference, Pune, India. http://www.tifr.res.in/icrc2005/
arxiv created 2005/06/24 · arxiv updated 2009/12/01
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∘ < |b| < 30∘) population, perhaps associated with the Gould belt, contributes to the gamma ray flux above 100 MeV.