HIGH-RESOLUTION X-RAY SPECTROSCOPY OF THE GALACTIC SUPERNOVA REMNANT PUPPIS A WITH<i>XMM-NEWTON</i>/RGS

Abstract

We present high-resolution X-ray spectra of cloud-shock interaction regions\nin the eastern and northern rims of the Galactic supernova remnant Puppis A,\nusing the Reflection Grating Spectrometer onboard the XMM-Newton satellite. A\nnumber of emission lines including K alpha triplets of He-like N, O, and Ne are\nclearly resolved for the first time. Intensity ratios of forbidden to resonance\nlines in the triplets are found to be higher than predictions by thermal\nemission models having plausible plasma parameters. The anomalous line ratios\ncannot be reproduced by effects of resonance scattering, recombination, or\ninner-shell ionization processes, but could be explained by charge-exchange\nemission that should arise at interfaces between the cold/warm clouds and the\nhot plasma. Our observations thus provide observational support for\ncharge-exchange X-ray emission in supernova remnants.\n