Deep X-Ray Imaging of the Central 20 Parsecs of the Galaxy with Chandra

Abstract

A deep observation toward the Galactic center with the Chandra X-Ray Observatory revealed a number of extended features, in addition to Sgr A* and SgrA East. Here, we focus on two curious, extended X-ray structures: large-scale (∼10 pc) bipolar lobes centered on Sgr A* and a bright cometary source located 0.3 pc from Sgr A*, CXOGC J174539.7-290020. The bipolar lobes consist of a number of emission clumps oriented along a line perpendicular to the Galactic plane, suggesting that a series of ejections has taken place on characteristic time scales of hundreds to thousands of years. The clumps are embedded in a low-intensity, edge-brightened lobe which is most evident in a flux ratio map. At two locations along the lobe, nonthermal linear features are present, suggesting that relativistic electrons may be impinging on the compressed, magnetic wall of this structure. The cometary X-ray source has no counterpart at other wavelengths; its orientation is consistent with a high-velocity neutron star ejected from the grouping of stars at IRS13, but there are problems with that hypothesis, and other models warrant consideration.