brightness profile as well as lower X-ray emission temperatures.'
author:
- 'Jonathan D. Slavin'
- 'Randall K. Smith'
- Adam Foster
- 'Henry D. Winter'
- 'John C. Raymond'
- 'Patrick O. Slane'
- Hiroya Yamaguchi
bibliography:
- 'snr\_evol.bib'
title: Numerical Simulations of Supernova Remnant Evolution in a Cloudy Interstellar Medium
---

Introduction
============

Supernovae are the primary source of hot gas in galaxies. The shocks created in a supernova explosion can expand to distances of more than 100 pc and create large, hot, low density volumes of gas that persist for millions of years. Supernova remnant (SNR) evolution has been explored theoretically for several decades with increasing levels of complexity. However, the appearance of SNRs and the way the shocks couple with the interstellar medium (ISM) depend crucially on the nature of the medium into which the remnant expands, in particular its density and inhomogeneity.

For many years SNRs were divided into two categories, shell-like and plerionic. The first category has emission that peaks at the edge of the remnant while plerions are centrally brightened. It was believed that in the latter case a pulsar wind powers the emission, while for shell-like remnants, emission from the outer blastwave shock 