The Composition and Energy Spectra of High Energy Cosmic Rays
S. P. Swordy
University of Chicago, Chicago, USA
The existing paradigm of the origin of galactic cosmic rays places
strong supernovae shocks as the acceleration site for this material.
However, although EGRET has reported evidence for GeV gamma rays from
some supernovae, it is still unclear if the signal is produced by
locally intense cosmic rays. Recent observations at TeV energies
have not managed to detect the emission expected to be produced by
an enhanced hadronic cosmic ray density near these objects. Although
non-thermal x-ray emissions have been detected and interpreted as
synchrotron emission from locally intense electrons at energies up
to ~100TeV, these results seem inconsistent with the electron source
spectrum inferred by direct measurements. It remains the case that
simple energetics provide the most convincing argument that supernovae
power the bulk of the observed cosmic rays. The extent to which
these issues can be supported by direct observations of high energy
cosmic rays will be examined.