Gamma-Ray Emission from Supernova Remnants and Surrounding Molecular Clouds

TL;DR

This paper reviews gamma-ray observations of supernova remnants and molecular clouds to evaluate their role in cosmic ray acceleration, highlighting ongoing efforts and unresolved questions in understanding cosmic ray origins.

Contribution

It provides a comprehensive review of recent gamma-ray observations and their implications for supernova remnants as cosmic ray sources.

Findings

Gamma-ray observations support supernova remnants as cosmic ray accelerators.

Evidence from molecular cloud interactions strengthens the case for supernova remnants.

Further observational and theoretical work is needed to conclusively determine cosmic ray origins.

Abstract

Galactic cosmic rays are believed to be accelerated at supernova remnant shocks. Gamma-ray observations of both supernova remnants and associated molecular clouds have been used in several occasions to test (so far quite successfully) this popular hypothesis. Despite that, a conclusive solution to the problem of cosmic ray origin is still missing, and further observational and theoretical efforts are needed. In this paper, the current status of these investigations is briefly reviewed.