Interaction of escaping cosmic rays with molecular clouds

TL;DR

This paper reviews how escaping cosmic rays interact with molecular clouds, highlighting their role in gamma-ray production, source identification, and propagation constraints in the interstellar medium.

Contribution

It provides a comprehensive overview of current understanding and recent developments in the study of cosmic ray interactions with molecular clouds.

Findings

Gamma-ray emissions help identify cosmic ray sources.

Interactions constrain cosmic ray propagation models.

Review of recent observational and theoretical progress.

Abstract

The study of the gamma-ray radiation produced by cosmic rays that escape their accelerators is of paramount importance for (at least) two reasons: first, the detection of those gamma-ray photons can serve to identify the sources of cosmic rays and, second, the characteristics of that radiation give us constraints on the way in which cosmic rays propagate in the interstellar medium. This paper reviews the present status of the field.