Cosmic-ray-induced ionization in molecular clouds adjacent to supernova remnants - Tracing the hadronic origin of GeV gamma radiation

Understand

Energetic gamma rays (GeV to TeV photon energy) have been detected toward several supernova remnants (SNR) associated with molecular clouds.

• If the gamma rays are produced mainly by hadronic processes rather than leptonic processes like bremsstrahlung, then the flux of energetic cosmic ray (CR) nuclei (>1 GeV) required to produce the gamma rays can be inferred at the site where the particles are accelerated in SNR shocks.
• It is of great interest to understand the acceleration of the CR of lower energy (<1 GeV) accompanying the energetic component.
• These particles of lower energy are most effective in ionizing interstellar gas, leaving an observable imprint on the interstellar ion chemistry.