Supernova Remnant Shock - Molecular Cloud Interactions: Masers as tracers of hadronic particle acceleration

TL;DR

This review discusses how shock-excited hydroxyl masers in supernova remnants interacting with molecular clouds serve as indicators of hadronic particle acceleration and explores new potential maser tracers for cosmic ray acceleration sites.

Contribution

It provides a comprehensive overview of shock-excited masers in supernova remnants and introduces a new maser tracer for cosmic ray acceleration sites.

Findings

Masers are linked to supernova remnants with molecular cloud interactions.

Masers trace sites of hadronic particle acceleration.

Potential new maser tracers for cosmic ray acceleration are discussed.

Abstract

We review the class of galactic supernova remnants which show strong interactions with molecular clouds, revealed through shock-excited hydroxyl masers. These remnants are preferentially found among the known GeV and TeV detections of supernova remnants. It has been argued that the masers trace out the sites of hadronic particle acceleration. We discuss what is known about the physical conditions of these shocked regions and we introduce a potential new maser tracer for identifying the sites of cosmic ray acceleration. This review includes a reasonably complete bibliography for researchers new to the topic of shock-excited masers and supernova remnants.