Fe K and ejecta emission in SNR G15.9+0.2 with XMM-Newton

TL;DR

This study analyzes XMM-Newton data of SNR G15.9+0.2, revealing ejecta, Fe K emission, and constraining the progenitor mass and distance, contributing new insights into its composition and evolution.

Contribution

First detection of Fe K line emission in SNR G15.9+0.2 and detailed analysis of its ejecta and progenitor characteristics.

Findings

Ejecta features indicate a massive star progenitor of 20-25 solar masses.

Fe K emission detected for the first time in this SNR.

Spatial variations in Fe K line properties observed.

Abstract

Aims: We present a study of the Galactic supernova remnant SNR G15.9+0.2 with archival XMM-Newton observations. Methods: EPIC data are used to investigate the morphological and spectral properties of the remnant, searching in particular for supernova ejecta and Fe K line emission. By comparing the SNR's X-ray absorption column density with the atomic and molecular gas distribution along the line of sight, we attempt to constrain the distance to the SNR. Results: Prominent line features reveal the presence of ejecta. Abundance ratios of Mg, Si, S, Ar, and Ca strongly suggest that the progenitor of SNR G15.9+0.2 was a massive star with a main sequence mass likely in the range 20-25 $M_{\odot}$, strengthening the physical association with a candidate central compact object detected with Chandra. Using EPIC's collective power, Fe K line emission from SNR G15.9+0.2 is detected for the first time. We measure the line properties and find evidence for spatial variations. We discuss how the source fits within the sample of SNRs with detected Fe K emission and find that it is the core-collapse SNR with the lowest Fe K centroid energy. We also present some caveats regarding the use of Fe K line centroid energy as a typing tool for SNRs. Only a lower limit of 5 kpc is placed on the distance to SNR G15.9+0.2, constraining its age to $t_{SNR} \gtrsim 2$ kyr.