X-ray imaging of supernova remnants and neutron stars - can we distinguish Type I remnants

The possibility of using X-ray imaging data to differentiate between Type I and Type II supernovae and to detect neutron stars in Type I remnants is considered. Based on an examination of Einstein Observatory X-ray images of supernova remnants, it is pointed out that, with the exceptions of Cas A and the Crab-like remnants, the structure of the interstellar medium dominates the X-ray emissivity of a remnent from early in its life. Imaging observations may, however, provide evidence for the type of event that created the remnant by allowing the estimation of the amount of ejecta thrown off in the explosion. X-ray observations have also been used to provide upper limits to the thermal emission from possible neutron stars in the five non-Crab-like historical remnants, which may indicate the lack of such objects and thereby impose constraints on the supernova model