Modeling the gamma-ray emission produced by runaway cosmic rays in the environment of RX J1713.7-3946

TL;DR

This paper models gamma-ray emission from runaway cosmic rays around supernova remnant RX J1713.7-3946, highlighting how different factors influence observable spectra and implications for gamma-ray observations.

Contribution

It provides detailed predictions of gamma-ray emission from runaway cosmic rays considering various environmental and source parameters, advancing understanding of cosmic ray interactions.

Findings

Gamma-ray spectra vary significantly with energy and environment.

Detection of enhanced emission depends on observation energy and conditions.

Results impact interpretation of gamma-ray data from supernova remnants.

Abstract

Diffusive shock acceleration in supernova remnants is the most widely invoked paradigm to explain the Galactic cosmic ray spectrum. Cosmic rays escaping supernova remnants diffuse in the interstellar medium and collide with the ambient atomic and molecular gas. From such collisions gamma-rays are created, which can possibly provide the first evidence of a parent population of runaway cosmic rays. We present model predictions for the GeV to TeV gamma-ray emission produced by the collisions of runaway cosmic rays with the gas in the environment surrounding the shell-type supernova remnant RX J1713.7-3946. The spectral and spatial distributions of the emission, which depend upon the source age, the source injection history, the diffusion regime and the distribution of the ambient gas, as mapped by the LAB and NANTEN surveys, are studied in detail. In particular, we find for the region surrounding RX J1713-3946, that depending on the energy one is observing at, one may observe startlingly different spectra or may not detect any enhanced emission with respect to the diffuse emission contributed by background cosmic rays. This result has important implications for current and future gamma-ray experiments.