Molecular Shocks and the Gamma-ray Clouds of the W28 Supernova Remnant

TL;DR

This paper investigates how the W28 supernova remnant influences nearby molecular clouds through shocks and cosmic rays, using multi-molecular line observations to understand gamma-ray emissions and cosmic-ray acceleration.

Contribution

It introduces a multi-molecular line observational approach to study the impact of supernova remnant shocks and cosmic rays on molecular clouds in W28.

Findings

Identification of chemically rich environments around W28

Characterization of shock and cosmic-ray interactions with molecular clouds

Preparation for future gamma-ray observations of cosmic-ray sources

Abstract

Interstellar medium clouds in the W28 region are emitting gamma-rays and it is likely that the W28 supernova remnant is responsible, making W28 a prime candidate for the study of cosmic-ray acceleration and diffusion. Understanding the influence of both supernova remnant shocks and cosmic rays on local molecular clouds can help to identify multi-wavelength signatures of probable cosmic-ray sources. To this goal, transitions of OH, SiO, NH3, HCO+ and CS have complemented CO in allowing a characterization of the chemically rich environment surrounding W28. This remnant has been an ideal test-bed for techniques that will complement arcminute-scale studies of cosmic-ray source candidates with future GeV-PeV gamma-ray observations.