Observations of supernova remnants and molecular clouds from the mm to the gamma-ray domain: bridging low and high energy cosmic rays

• Main Authors: Gabici, Stefano, Montmerle, Thierry
• Format: Journal Article
• Language: English
• Published: 07-10-2015
• Subjects: Physics - High Energy Astrophysical Phenomena
• DOI: 10.48550/arxiv.1510.02102

New evidence that cosmic rays (hadronic component) are accelerated by
supernova remnant shocks all the way from low energies to high energies, has
come from recent works combining gamma-ray observations in the sub-GeV to TeV
domain on the one hand, and in the submm-mm domain on the other hand. These
observations concern the specific cases of supernova remnants interacting with
molecular cloud complexes, that have long been suspected to be ideal
laboratories to study in situ cosmic ray acceleration and diffusion. Indeed,
enhanced gamma-ray emission from neutral pion decay, as well as enhanced
ionization (both by at least one order of magnitude with respect to average
galactic values) have been observed in several regions of massive star
formation housing supernova remnants interacting with molecular cloud
complexes. This paper summarizes the main physical and chemical processes at
work, as well as recent observations, that further support the paradigm of
cosmic ray acceleration by supernova remnants all the way from the MeV domain
up to several tens of TeV, although much work remains to be done to understand
cosmic ray penetration and diffusion inside and around molecular clouds, and
reveal the actual spectrum of the accelerated cosmic rays.