Electrons from galactic accelerators
Electrons are likely to be accelerated together with nuclear cosmic-ray particles in galactic sources. If the source material is regular matter around supernova remnants, and if positrons from β+ decay of unstable nuclei such as 56Co from the supernova explosion do not contribute significantly, the accelerated particles are not expected to contain a significant fraction of positrons. Observationally, it is now well established that the intensity of electrons exceeds that of positrons by more than a factor of 10, at least up to energies where charge identification has been possible (i.e. up to at most 100 GeV). This leads to the conclusion that the electron flux is dominated by particles from primary acceleration sites in this region.