2006/10/31 by Anthony R. Pullen, Ranga-Ram Chary, Ranga‐Ram Chary +1 · 2 citations
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Dark Matter and Cosmic Phenomena #Particle physics theoretical and experimental studies #astro-ph
paper · pdf · doi:10.1103/physrevd.76.063006
published as Phys.Rev.D76:063006,2007 · Accepted for publication in PRD; 8 pages; 9 figures; 3 tables; text changed to clarify several points; conclusions unchanged
arxiv created 2007/07/27 · openalex publication_date 2007/09/17 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
We search data from the Energetic Gamma Ray Experiment Telescope (EGRET) for a gamma-ray line in the energy range 0.1--10 GeV from the 10\ifmmode^∘\else\textdegree\fi\ifmmode×\else\texttimes\fi10\ifmmode^∘\else\textdegree\fi region around the Galactic center. Our null results lead to upper limits to the line flux from the Galactic center. Such lines may have appeared if the dark matter in the Galactic halo is composed of weakly interacting massive particles (WIMPs) in the mass range 0.1--10 GeV. For a given dark-matter-halo model, our null search translates to upper limits to the WIMP two-photon annihilation cross section as a function of WIMP mass. We show that, for a toy model in which Majorana WIMPs in this mass range annihilate only to electron-positron pairs, these upper limits supersede those derived from measurements of the 511-keV line and continuum photons from internal bremsstrahlung at the Galactic center.