UPDATED RADIO [SIGMA]--D RELATION FOR GALACTIC SUPERNOVA REMNANTS--II

In this paper we present the updated empirical radio surface-brightness-to-diameter ([SIGMA]-D) relation for Galactic supernova remnants (SNRs) calibrated using 110 SNRs with reliable distances. We apply orthogonal fitting procedure and kernel density smoothing in the [SIGMA]--D plane and compare the results with the latest theoretical [SIGMA]--D relations derived from simulations of radio evolution of SNRs. We argue that the best agreement between the empirical and simulated [SIGMA]--D relations is achieved if the mixed-morphology SNRs and SNRs of both, low brightness and small diameter, are filtered out from the calibration sample. The distances to 5 newly discovered remnants and 27 new candidates for shell SNRs are estimated from our full and filtered calibration samples. Key words. Methods: data analysis--Methods: statistical--Astronomical data bases: miscellaneous--ISM: supernova remnants--Radio continuum: ISM