D. A. Green
Mullard Radio Astronomy Observatory, Cavendish
Laboratory, Madingley Road, Cambridge CB3 0HE, United
Kingdom
Abstract. A catalogue of 231 Galactic supernova remnants (SNRs)
is presented, and the selection effects applicable to the identification
of remnants at radio wavelengths are discussed. In addition to missing
low surface brightness remnants, small angular size i.e. young but
distant remnants are also missing from the current catalogue of
Galactic SNRs. Several statistical properties of Galactic SNRs are
discussed, including the surface-brightness diameter (Sigma-D) relation. It
is concluded that the wide range of intrinsic properties of Galactic
remnants with known distances, together with the observational selection
effects, means that use of the Sigma-D relation to derive diameters and hence
distances for individual SNRs, or for statistical studies, is highly
uncertain. The observed distribution of bright SNRs, which are thought
to be largely free from selection effects, is also used to derive a simple
model for the distribution of SNRs with Galactocentric radius.
Keywords: supernova remnants catalogues radio continuum: ISM Galaxy: structure ISM: general