X-RAY SPECTROSCOPY OF POTENTIAL SMALL MAGELLANIC CLOUD TYPE Ia SUPERNOVA REMNANTS AND THEIR ENVIRONMENTS

We examine three supernova remnants in the SMC, IKT 5 (supernova remnant (SNR) 0047-73.5), IKT 25 (SNR 0104-72.3), and DEM S 128 (SNR 0103-72.4), which are designated as Type Ia in the literature due to their spectra and morphology. This is troublesome because of their asymmetry, a trait not usually associated with young Type Ia remnants. We present Chandra X-ray Observatory data on these three remnants and perform a maximum likelihood analysis on their spectra. We find that the X-ray emission is dominated by interactions with the interstellar medium. In spite of this, we find a significant Fe overabundance in all three remnants. Through examination of radio, optical, and infrared data, we conclude that these three remnants are likely not Type Ia SNRs. We detect potential point sources that may be members of the progenitor systems of both DEM S 128 and IKT 5, which could suggest these could be Fe-rich core-collapse remnants.