Can Ejecta‐dominated Supernova Remnants be Typed from Their X‐Ray Spectra? The Case of G337.2−0.7

Abstract

In this paper we use recent X-ray and radio observations of the ejecta-rich Galactic SNR G337.2-0.7 to determine properties of the SN explosion that formed this source. H I absorption measurements from ATCA constrain the distance to G337.2-0.7 to lie between 2.0+/-0.5 and 9.3+/-0.3 kpc. Combined with a clear radio image of the outer blast wave, this distance allows us to estimate the dynamical age (between 750 and 3500 yr) from the global X-ray spectrum obtained with the XMM-Newton and Chandra observatories. The presence of ejecta is confirmed by the pattern of fitted relative abundances, which show Mg, Ar, and Fe to be less enriched (compared to solar) than Si, S, or Ca, and the ratio of Ca to Si to be 3.4+/-0.8 times the solar value (under the assumption of a single electron temperature and single ionization timescale). With the addition of a solar abundance component for emission from the blast wave, these abundances (with the exception of Fe) resemble the ejecta of a Type Ia, rather than core-collapse, SN. Comparing directly to models of the ejecta and blast wave X-ray emission calculated by evolving realistic SN Ia explosions to the remnant stage allows us to deduce that one-dimensional delayed-detonation and pulsed delayed-detonation models can indeed reproduce the major features of the global spectrum. In particular, stratification of the ejecta, with the Fe shocked most recently, is required to explain the lack of prominent Fe K emission.