The distribution of SNRs with Galactocentric radius

TL;DR

This paper analyzes the distribution of supernova remnants in the Galaxy by comparing observed bright SNRs with models of their Galactocentric radius distribution, avoiding distance estimation issues and providing new constraints on their spatial distribution.

Contribution

It introduces a method to constrain SNR distribution without relying on distance estimates, using bright SNRs and model comparison to improve understanding of their Galactic placement.

Findings

Best-fit models are more concentrated towards the Galactic center.

The distribution differs from previous models by Case & Bhattacharya.

Method avoids biases from distance estimation techniques.

Abstract

In order to determine the Galactic distribution of supernova remnants (SNRs) there are two main difficulties: (i) there are selection effects which mean that catalogues of SNRs are not complete, and (ii) distances are not available for most SNRs, so distance estimates from the `Sigma-D' relation are used. Here I compare the observed distribution of 69 `bright' SNRs with Galactic longitude with that expected from the projection of various model Galactocentric radius distributions. This does not require distances from the `Sigma-D' relation, and selecting only `bright' remnants aims to avoid major issues with the selection effects. Although this method does not provide a direct inversion to the 3-D distribution of SNRs in the Galaxy, it does provide useful constraints on the Galactocentric radius distribution. For a combined power-law/exponential model for SNR surface density variation with Galactocentric radius, the best fitted distributions are more concentrated towards lower radii than the distribution derived by Case & Bhattacharya.