2008/01/31 by A. A. Abdo, B. Allen, T. Aune +37 · 2 citations
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Dark Matter and Cosmic Phenomena #Gamma-ray bursts and supernovae #astro-ph
paper · pdf · doi:10.1103/physrevlett.101.221101
published as Phys.Rev.Lett.101:221101,2008 · Submitted to PhysRevLett
arxiv created 2008/10/14 · openalex publication_date 2008/11/24 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The 7 year data set of the Milagro TeV observatory contains 2.2 x 10(11) events of which most are due to hadronic cosmic rays. These data are searched for evidence of intermediate scale structure. Excess emission on angular scales of approximately 10 degrees has been found in two localized regions of unknown origin with greater than 12sigma significance. Both regions are inconsistent with pure gamma-ray emission with high confidence. One of the regions has a different energy spectrum than the isotropic cosmic-ray flux at a level of 4.6sigma, and it is consistent with hard spectrum protons with an exponential cutoff, with the most significant excess at approximately 10 TeV. Potential causes of these excesses are explored, but no compelling explanations are found.