H i absorption spectra toward MAGPIS supernova remnant candidates

Abstract

The Multi-Array Galactic Plane Imaging Survey is an ongoing project to map out the northern Galactic plane in the 21 cm radio continuum. The survey identified 30 probable supernova remnant candidates in the Galactic plane from 18° < 32°. H I absorption spectra were taken toward these sources using data from the VLA Galactic Plane Survey. Using both circular and hydrodynamical Galactic rotation models, the corresponding distances were calculated. Of the 30 candidates, distances to nine of them were determined, and another eight sources had their distances constrained with upper and lower bounds. Many of these sources have detectable radio recombination line emission toward them, and we comment on the possible nature of these emissions. © 2009 The American Astronomical Society. All rights reserved.