Discovery of X-Ray-Emitting O-Ne-Mg-Rich Ejecta in the Galactic Supernova Remnant Puppis A

TL;DR

This study reports the discovery of X-ray-emitting O-Ne-Mg-rich ejecta in the supernova remnant Puppis A, revealing new insights into its composition and shock interactions through spatially-resolved spectral analysis.

Contribution

It identifies and characterizes O-Ne-Mg-rich ejecta in Puppis A using X-ray line ratios, providing new evidence of ejecta composition and shock-heated features in this remnant.

Findings

Detection of O-Ne-Mg-rich ejecta with supersolar abundances

Identification of a low-ionization filament with ejecta characteristics

Spatial analysis showing ejecta and interstellar medium regions

Abstract

We report on the discovery of X-ray--emitting O-Ne-Mg-rich ejecta in the middle-aged Galactic O-rich supernova remnant Puppis A with Chandra and XMM-Newton. We use line ratios to identify a low-ionization filament running parallel to the northeastern edge of the remnant that requires supersolar abundances, particularly for O, Ne, and Mg, which we interpret to be from O-Ne-Mg-rich ejecta. Abundance ratios of Ne/O, Mg/O, and Fe/O are measured to be ~2, ~2, and <0.3 times the solar values. Our spatially-resolved spectral analysis from the northeastern rim to the western rim otherwise reveals sub-solar abundances consistent with those in the interstellar medium. The filament is coincident with several optically emitting O-rich knots with high velocities. If these are physically related, the filament would be a peculiar fragment of ejecta. On the other hand, the morphology of the filament suggests that it may trace ejecta heated by a shock reflected strongly off the dense ambient clouds near the northeastern rim.