A Super Bubble Candidate in the Galactic Center and a Local Enhancement G359.77-0.09

TL;DR

This paper reports the discovery of a ring-like X-ray structure near the Galactic center, likely a super bubble, characterized by thermal plasma emission and containing two diffuse sources with high absorption consistent with the Galactic center distance.

Contribution

It identifies a new super bubble candidate in the Galactic center region based on X-ray observations and spectral analysis.

Findings

Discovery of a 49x40 pc ring-like X-ray structure near the Galactic center.

Identification of two diffuse sources within the ring with similar thermal spectra.

Estimated thermal energy of the structure is approximately 10^51 erg.

Abstract

A 20' \times 16' elliptical ring-like structure has been found near the Galactic center in the narrow energy band corresponding to the K$\alpha$ line from He-like sulfur. In the ring, two diffuse sources are found, a supernova remnant candidate G359.79-0.26 and an unidentified source G359.77-0.09. The X-ray spectrum of G359.77-0.09 is similar to that of G359.79-0.26, which can be explained by an absorbed thin thermal plasma model with temperatures of 0.7 and 1.0 keV. The absorption column densities of these two sources are large (N_H = 6.9 \times 10^{22} and 4.5 \times 10^{22} cm^{-2}) and are consistent with that of the Galactic center distance. The X-ray spectrum extracted from the ring-like structure is also represented by an absorbed thin thermal plasma model (kT_e \sim 0.9 keV). The thermal energy of the plasma filling the ring-like structure is estimated to be 1.0 \times 10^{51} erg. We therefore propose that the two sources comprise a single ring-like object, which is possibly a super bubble with a size of 49 pc \times 40 pc in the Galactic center region.