ELEMENTAL ABUNDANCES IN THE POSSIBLE TYPE Ia SUPERNOVA REMNANT G344.7-0.1

Abstract

Recent studies on the Galactic supernova remnant (SNR) G344.7-0.1 have\ncommonly claimed its origin to be a core-collapse supernova (SN) explosion,\nbased on its highly asymmetric morphology and/or proximity to a star forming\nregion. In this paper, however, we present an X-ray spectroscopic study of this\nSNR using Suzaku, which is supportive of a Type Ia origin. Strong K-shell\nemission from lowly ionized Fe has clearly been detected, and its origin is\ndetermined, for the first time, to be the Fe-rich SN ejecta. The abundance\npattern is highly consistent with that expected for a somewhat-evolved Type Ia\nSNR. It is suggested, therefore, that the X-ray point-like source CXOU\nJ170357.8-414302 located at the SNR's geometrical center is not associated with\nthe SNR but is likely to be a foreground object. Our result further indicates\nthat G344.7-0.1 is the first possible Type Ia SNR categorized as a member of\nthe so-called "mixed-morphology" class. In addition, we have detected emission\nfrom He-like Al at ~1.6 keV, the first clear detection of this element in the\nspectrum of an extended X-ray source. The possible enhancement of the Al/Mg\nabundance ratio from the solar value suggests that the ambient interstellar\nmedium has a relatively high metallicity (not less than 10% of the solar\nvalue), if this SNR has indeed a Type Ia origin. We also report marginal\ndetection of Cr and Mn, although the measured fluxes have large statistical and\nsystematic uncertainties.\n