Diffuse X-Rays from the Inner 3 Parsecs of the Galaxy

Abstract

Recent observations with the Chandra X-ray Observatory have provided us with the capability to discriminate point sources, such as the supermassive black hole Sgr A*, from the diffuse emission within the inner 10'' of the Galaxy. The hot plasma producing the diffuse X-radiation, estimated at ~7.6*10^{31} ergs s^{-1} arcsec^{-2} in the 2-10 keV band, has a RMS electron density ~26 cm^{-3} and a temperature kT ~= 1.3 keV, with a total inferred mass of ~0.1 solar masses. At least some of this gas must be injected into the ISM via stellar winds. In the most recent census, about 25 bright, young stars have been identified as the dominant sources of the overall mass efflux from the Galactic center. In this paper, we use detailed 3-dimensional SPH simulations to study the wind-wind interactions occurring in the inner 3 parsecs of the Galaxy, with a goal of understanding what fraction, if any, of the diffuse X-ray flux measured by Chandra results from the ensuing shock heating of the ambient medium. We conclude that this process alone can account for the entire X-ray flux observed by Chandra in the inner 10'' of the Galaxy. Understanding the X-ray morphology of the environment surrounding Sgr A* will ultimately provide us with a greater precision in modeling the accretion of gas onto this object, which appears to be relatively underluminous compared to its brethren in the nuclei of other galaxies.