XMM-Newton and Chandra observations of G272.2-3.2. Evidence of stellar ejecta in the central region

TL;DR

This study uses X-ray, radio, and Hα observations to analyze the supernova remnant G272.2-3.2, revealing ejecta signatures, a likely Type Ia origin, and insights into its ionization state, structure, and surrounding environment.

Contribution

It provides the first detailed spatially resolved X-ray spectral analysis of G272.2-3.2, identifying ejecta features and constraining its progenitor type and evolutionary history.

Findings

Ejecta material shows elevated Si, S, and Fe abundances.

Remnant likely originated from a Type Ia supernova.

Remnant expanded in a denser medium than uniform models suggest.

Abstract

We aim to study the spatial distribution of the physical and chemical properties of the X-ray emitting plasma of the supernova remnant G272.2-3.2, in order to get important constraints on its ionization stage, on the progenitor supernova explosion, and the age of the remnant. We report combined XMM-Newton and Chandra images, median photon energy map, silicon and sulfur equivalent width maps, and a spatially resolved spectral analysis for a set of regions of the remnant. Complementary radio and H{\alpha} observations, available in the literature, are also used to study the multi-wavelength connection of all detected emissions. The X-ray morphology of the remnant displays an overall structure with an almost circular appearance, a centrally brightened hard region, with a peculiar elongated hard structure oriented along the northwest-southeast direction of the central part. The X-ray spectral study of the regions shows distinct K{\alpha} emission-line features of metal elements, confirming the thermal origin of the emission. The X-ray spectra are well represented by an absorbed VNEI thermal plasma model, which produces elevated abundances of Si, S, and Fe in the circular central region, typical of ejecta material. The values of abundances found in the central region of the SNR favor a Type Ia progenitor for this remnant. The outer region shows abundances below the solar value, as expected if the emission arises from the shocked ISM. The relatively low ionization timescales suggests non-equilibrium ionization. We identify the location of the contact discontinuity. Its distance to the outer shock is higher than expected for expansion in a uniform media, what suggests that the remnant spent most of its time in a more dense medium.