33RD INTERNATIONAL COSMIC RAY CONFERENCE, RIO DE JANEIRO 2013 THE ASTROPARTICLE PHYSICS CONFERENCE The 1st Fermi-LAT SNR Catalog: Probing the Gamma-ray Population

Abstract: While supernova remnants (SNRs) are widely thought to be powerful accelerators, evidence comes largely from a small number of well-studied cases. Here we systematically determine the γ-ray emission from all known Galactic SNRs, disentangling them from the sea of Galactic cosmic rays. Using Fermi-LAT data we have characterized the GeV emission in all regions containing SNRs, accounting for systematic uncertainties caused by source confusion, diffuse emission modeling, and instrumental response. More than a dozen remnants are identified through spatial extension or detection at TeV energies, with potential associations for>40 more. From this population study, two clear classes of γ-ray-emitting SNRs emerge: young remnants and those interacting with a dense medium. This large statistical sample also reveals a possible correlation between GeV and radio flux. The growing number of identified SNRs will help to disentangle the effects of age and environment on the aggregate properties of SNRs at high energies