Two New Ejecta-Dominated Galactic Supernova Remnants: G337.2-0.7 and G309.2-0.6

Abstract

We present the analysis of new X-ray observations of two Galactic radio supernova remnants (SNRs), G337.2-0.7 and G309.2-0.6. Both remnants exhibit line-rich thermal spectra that require highly non-solar elemental abundance ratios. In each case, Si and S are unequivocally overabundant compared to solar based purely on the measured equivalent width of the K$\alpha$ line complex. Detailed nonequilibrium ionization spectral analysis of these remnants, using a single temperature, single ionization age model, confirm the overabundances, yielding Si, S and Ar abundances many times their solar values: 3 to 5 times solar for G337.2-0.7 and greater than 3 to 10 times solar for G309.2-0.6. We also find that for both remnants, Ne and Mg are underabundant relative to Si, and for G309.2-0.6, Ca and Fe as well are relatively underabundant. This is the first detection of metal-rich, non-solar abundance material in these remnants, identifying them as young ejecta-dominated SNRs. Further support for their youth comes from the distances that we estimate from the fitted column densities (less than 15 kpc for G337.2-0.7, and $4\pm 2$ kpc for G309.2-0.6). From the implied sizes of the remnants at these distances we infer relatively young ages (2000 to 4500 years for G337.2-0.7, and 700 to 4000 years for G309.2-0.6). Finally we note that no compact object has yet been found within G337.2-0.7, but an X-ray point source is evident within the radio shell of G309.2-0.6, although its nature remains unknown.

23 pages, 8 figures, ApJ, accepted

References in corpus (8)

• Nucleosynthesis in Type Ia Supernovae
• Nucleosynthesis and Mixing in Cassiopeia A
• ASCA X-Ray Spectroscopy of LMC Supernova Remnants and the Metal Abundances of the LMC
• Electron Heating and Cosmic Rays at a Supernova Shock from Chandra X-ray Observations of E0102.2-7219
• The Distance to the Soft Gamma Repeater SGR 1627-41
• G309.2-00.6 and jets in supernova remnants
• An analysis of the X-ray emission from the supernova remnant 3C397
• Discovery of X-ray Emission from G328.4+0.2, a Crab-Like Supernova Remnant

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