The radial supernova remnant distribution in the Galaxy
  Supernovae 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 supernovae in the Milky Way is based
mostly on the study of Galactic supernova remnants (SNRs), providing an
(incomplete) record to supernova 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 supernova activity
is present in the Galactic Centre region. However, the presence of a magnetar
and a SNR near the Galactic Centre suggest that a spatial distribution with
zero SNRs at the Galactic Centre is not realistic. In light of these concerns
we reevaluate 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.
