The radial supernova remnant distribution in the Galaxy

Abstract

ABSTRACT Supernovae (SNe) are the dominant source of chemical enrichment of galaxies, and they are an important source of energy to heat the interstellar medium and accelerate cosmic rays. Our knowledge of SNe in the Milky Way is based mostly on the study of Galactic supernova remnants (SNRs), providing an (incomplete) record to SN activity over the last ∼100 000 yr. Here, we report on an investigation of the spatial distribution of Galactic SNRs. Given the limited number of SNRs, it is common to assume a functional form for the Galactocentric distribution of SNRs. However, several functional forms have been used in the past, without much justification for the radial distribution. For example, one often used functional form implies that no SN activity is present in the Galactic Centre region. However, the presence of a magnetar and an SNR near the Galactic Centre suggests that a spatial distribution with zero SNRs at the Galactic Centre is not realistic. In light of these concerns, we re-evaluate the Galactic SNR distribution. We provide a brief outline of the main detection biases in finding SNRs and we investigate whether or not the use of the most common functional form is justified and how it compares to other models for the SNR distribution. We do this by analysing the longitudinal distribution of SNRs. We find that a simple exponential distribution is the most consistent and simplest model for describing the radial SNR distribution in the Galaxy and draw comparisons with the massive star formation and metallicity distributions.