[Paper Review] The X-ray diffuse emission from the Galactic Center

L. Sidoli, S. Mereghetti|arXiv (Cornell University)|Aug 16, 1999

Atomic and Molecular Physics3 citations

TL;DR

Using a long BeppoSAX observation, this study identifies two thermal plasma components in the Galactic Center's diffuse X-ray emission: a soft component at ~0.6 keV and a hard component at ~8–9 keV. The soft X-rays strongly correlate with the SgrA East radio halo, supporting the interpretation of SgrA East as an evolved supernova remnant.

ABSTRACT

A long BeppoSAX observation of the Galactic Center region shows that the spectrum of the diffuse X-ray emission from the SgrA Complex can be described with the sum of two thermal plasma models with temperatures of ~0.6 keV and \~8-9 keV. The spatial distribution of the diffuse emission is energy dependent. While the hard X-ray emission has a nearly symmetric distribution elongated along the Galactic Plane, the soft X-rays (E < 5 keV) are remarkably well correlated with the triangular radio halo of SgrA East. The parameters derived for the soft component support the interpretation of the SgrA East shell in terms of an evolved supernova remnant.

Motivation & Objective

• To characterize the spectral and spatial properties of diffuse X-ray emission in the Galactic Center region.
• To determine whether the diffuse X-ray emission can be explained by thermal plasma models.
• To investigate the spatial correlation between soft X-ray emission and the SgrA East radio halo.
• To assess the physical interpretation of SgrA East as an evolved supernova remnant based on X-ray data.
• To understand the energy-dependent spatial distribution of diffuse X-ray emission in the SgrA Complex.

Proposed method

• Conducted a long observation of the Galactic Center region using the BeppoSAX X-ray satellite.
• Fitted the observed X-ray spectrum with a sum of two thermal plasma models to describe the diffuse emission.
• Analyzed the spatial distribution of X-ray emission across different energy bands (soft vs. hard X-rays).
• Compared the soft X-ray emission (E < 5 keV) with the triangular radio halo of SgrA East to assess spatial correlation.
• Used spectral fitting techniques to derive plasma temperatures, emission measures, and abundances.
• Evaluated the consistency of the derived parameters with the supernova remnant model for SgrA East.

Experimental results

Research questions

• RQ1 What are the dominant physical components contributing to the diffuse X-ray emission in the Galactic Center?
• RQ2 How does the spatial distribution of X-ray emission vary with energy, particularly between soft and hard X-rays?
• RQ3 To what extent is the soft X-ray emission spatially correlated with the SgrA East radio halo?
• RQ4 Can the observed X-ray spectrum be explained by thermal plasma emission, and what are the derived plasma temperatures?
• RQ5 Do the derived X-ray parameters support the hypothesis that SgrA East is an evolved supernova remnant?

Key findings

• The diffuse X-ray spectrum in the SgrA Complex is best described by the sum of two thermal plasma components with temperatures of approximately 0.6 keV and 8–9 keV.
• The soft X-ray emission (E < 5 keV) shows a strong spatial correlation with the triangular radio halo of SgrA East.
• The hard X-ray emission is nearly symmetric and elongated along the Galactic Plane, indicating a different spatial origin than the soft component.
• The derived parameters for the soft X-ray component are consistent with the interpretation of SgrA East as an evolved supernova remnant.
• The energy-dependent spatial distribution of the emission suggests distinct physical origins for the soft and hard X-ray components.
• The spectral fitting results support a two-component model rather than a single-component or non-thermal explanation for the diffuse emission.