Global Distribution of Ionizing and Recombining Plasmas in the Supernova Remnant G290.1$-$0.8

TL;DR

This study analyzes Suzaku X-ray data of supernova remnant G290.1-0.8, revealing regions of recombining plasma with over-solar abundances, indicating complex ejecta-ISM interactions and plasma evolution.

Contribution

First detection of recombining plasma in G290.1-0.8, distinguishing ejecta and ISM origins, and proposing a breakout scenario for plasma formation.

Findings

Recombining plasma features are prominent in the northwest region.

Recombining plasma has over-solar abundances, indicating ejecta origin.

Ionizing plasma has roughly solar abundances, indicating ISM origin.

Abstract

We report on the Suzaku results of the mixed-morphology supernova remnant (SNR) G290.1$-$0.8 (MSH 11-61A). The SNR has an asymmetric structure extended to the southeast and the northwest. In the X-ray spectra of the center and the northwest regions, we discover recombining plasma features with the strong Si Ly$\alpha$ and radiative recombination continuum at $\sim$ 2.7 keV. These features are the most significant in the northwest region, and the spectra are well-reproduced with a recombining plasma of $kT_{\rm e} = 0.5$ keV. Whereas the spectra of other regions are expressed by an ionizing plasma of $kT_{\rm e} = 0.6$ keV. The recombining plasma has over-solar abundances, while the ionizing plasma has roughly solar abundances. Hence they are likely ejecta and interstellar medium (ISM) origin, respectively. The recombining plasma in the northwest of G290.1$-$0.8 would be generated by a break-out of the supernova ejecta from a high density circumstellar medium to a low density ISM.