High-Resolution X-Ray Spectroscopy of the Galactic Supernova Remnant Puppis A with the XMM-Newton RGS

TL;DR

This study uses high-resolution X-ray spectroscopy to detect charge-exchange emission in the supernova remnant Puppis A, revealing new insights into cloud-shock interactions and plasma processes.

Contribution

First detection of charge-exchange X-ray emission in a supernova remnant using high-resolution spectra, highlighting the importance of this process in SNRs.

Findings

Resolved emission lines of He-like N, O, Ne for the first time.

Observed line ratios inconsistent with thermal models, suggesting charge-exchange.

Provided observational evidence supporting charge-exchange emission in SNRs.

Abstract

We present high-resolution X-ray spectra of cloud-shock interaction regions in the eastern and northern rims of the Galactic supernova remnant Puppis A, using the Reflection Grating Spectrometer onboard the XMM-Newton satellite. A number of emission lines including K alpha triplets of He-like N, O, and Ne are clearly resolved for the first time. Intensity ratios of forbidden to resonance lines in the triplets are found to be higher than predictions by thermal emission models having plausible plasma parameters. The anomalous line ratios cannot be reproduced by effects of resonance scattering, recombination, or inner-shell ionization processes, but could be explained by charge-exchange emission that should arise at interfaces between the cold/warm clouds and the hot plasma. Our observations thus provide observational support for charge-exchange X-ray emission in supernova remnants.