On the metal abundances inside mixed-morphology supernova remnants: the case of IC443 and G166.0+4.3

TL;DR

This study uses XMM-Newton data to analyze metal abundances in two mixed-morphology supernova remnants, revealing non-uniform distributions of elements and challenging existing models, thus highlighting the need for more detailed theories.

Contribution

It provides spatially resolved spectral analysis of IC443 and G166.0+4.3, discovering metal-rich regions and demonstrating limitations of current models for MMSNRs.

Findings

Enhanced Ne, Mg, Si in IC443's northern peak

S enrichment in G166.0+4.3's outer regions

Existing models fail to explain observed abundance distributions

Abstract

Recent developments on the study of mixed morphology supernova remnants (MMSNRs) have revealed the presence of metal rich X-ray emitting plasma inside a fraction of these remnant, a feature not properly addressed by traditional models for these objects. Radial profiles of thermodynamical and chemical parameters are needed for a fruitful comparison of data and model of MMSNRs, but these are available only in a few cases. We analyze XMM-Newton data of two MMSNRs, namely IC443 and G166.0+4.3, previously known to have solar metal abundances, and we perform spatially resolved spectral analysis of the X-ray emission. We detected enhanced abundances of Ne, Mg and Si in the hard X-ray bright peak in the north of IC443, and of S in the outer regions of G166.0+4.3. The metal abundances are not distributed uniformly in both remnants. The evaporating clouds model and the radiative SNR model fail to reproduce consistently all the observational results. We suggest that further deep X-ray observations of MMSNRs may reveal more metal rich objects. More detailed models which include ISM-ejecta mixing are needed to explain the nature of this growing subclass of MMSNRs.