A SEARCH FOR COSMIC-RAY ACCELERATION BY SUPERNOVA REMNANT SHOCKS

The debate concerning the manner in which cosmic rays are accelerated is a continuing one but shocks associated with supernova remnants (SNR) are strong theoretical favourites, at least at energies below 10(14) eV. Experimental evidence is largely lacking, however, although we and others have previously claimed evidence for excesses of gamma-ray intensity and associated parent cosmic-ray particles associated with SNR, most particularly the prominent large remnant, Loop I. With the advent of the Compton Gamma Ray Observatory it is possible to check the hypothesis in two ways: by identifying gamma-ray excesses and by finding spectral changes as one crosses the SNR boundaries. We present here the results of such a study which, to us, appear to give some support.