information:highlighting, structural:expansion, structural:scholar_edition
Cosmic rays

Supernova remnants are thought to accelerate a large fraction of galactic primary cosmic rays, but direct evidence for cosmic ray production has only been found in a small number of remnants. Gamma rays from pion -decay have been detected from the supernova remnants IC 443 and W44. These are produced when accelerated protons from the remnant impact on interstellar material.