Particle acceleration in SNRs Original Research Article

We present the results of hard X-ray emissions from the shell of supernova remnants (SNR) revealed with the ASCA imaging and spectroscopic observations. The hard X-ray spectra and morphologies are consistent with synchrotron emission from extremely high energy electrons of 10–100 TeV. We infer that significant fractions of the Galactic cosmic rays below the energy of 1014.5 eV are produced by the Fermi acceleration mechanisms at the shocked shell of SNRs.