Origin of TeV Galactic cosmic rays
Résumé
We consider a possibility of identification of sources of cosmic rays (CR) of the energy above 1 TeV via observation of degree-scale extended γ-ray emission which traces the locations of recent sources in the Galaxy. Such emission in the energy band above 100 GeV is produced by CR nuclei and electrons released by the sources and spreading into the interstellar medium. We use the data from the Fermi γ-ray telescope to locate the degree-scale 100 GeV γ-ray sources. We find that the number of such sources and their overall power match to those expected when CRs injection events happen every ˜100yr in portions of ˜1050erg. We find that most of the sources are associated to pulsars with spin-down age less than ˜30kyr and hence to the recent supernova explosions. This supports the hypothesis of supernova origin of Galactic CRs. We notice that the degree-scale extended emission does not surround shell-like supernova remnants without pulsars. Based on this observation, we argue that the presence of the pulsar is essential for the CR acceleration process. We expect that a significant fraction of the degree-scale sources should be detectable as extended sources with km3-scale neutrino detectors.