Isolating Sgr A East: The First Uncontaminated X-ray Maps of a Galactic Center Supernova Remnant

TL;DR

This study uses advanced analysis of deep Chandra X-ray data to isolate the supernova remnant Sgr A East in the Galactic Center, revealing its true properties free from contamination.

Contribution

The paper introduces a novel application of Poissonian GMCA to disentangle overlapping X-ray components in the Galactic Center, enabling accurate characterization of Sgr A East.

Findings

Fe emission is centrally concentrated, characteristic of mixed-morphology SNRs.

Isolated Sgr A East shows lower ionization age and higher electron density.

Separation improves the robustness of SNR property measurements.

Abstract

The central few parsecs of the Milky Way host a complex X-ray-emitting environment in which several extended plasma components are blended along the line of sight, complicating attempts to measure the intrinsic properties of individual components. In particular, the supernova remnant (SNR) Sgr A East is strongly confused with the stellar wind-fed plasma associated with Sagittarius A* and the surrounding nuclear environment. Here we apply Poissonian Generalized Morphological Component Analysis (pGMCA) to deep, stacked Chandra ACIS-I observations of the Galactic Center to disentangle these overlapping X-ray components. By comparing the separated X-ray components with multiwavelength data, we identify the location of the reflected shock in Sgr A East and construct spatially resolved maps of Fe and S/Ar/Ca emission. The Fe emission is centrally concentrated, consistent with the properties of mixed-morphology supernova remnants. Separating the SNR emission from the shocked wind plasma around Sgr A* allows us to recover uncontaminated SNR properties and improve the robustness of the derived parameters. Spectral modeling of the isolated Sgr A East component reveals a lower ionization age and a higher electron density than previously reported, indicating strong interaction with dense surrounding material.