Nuclear de-excitation line spectrum of Cassiopeia A
Nuclear de-excitation line spectrum of Cassiopeia A
Context. The supernova remnant Cassiopeia A is a prime candidate for accelerating cosmic ray protons and ions. Gamma rays have been observed at GeV and TeV energies, which indicates hadronic interactions, but they could also be caused by inverse-Compton scattering of low-energy photons by accelerated electrons.