The Hot Interstellar Medium of the Galactic Center: Observations with Chandra

Abstract

Deep observations of the Galactic center with the ACIS instrument on the Chandra X-ray Observatory reveal a wealth of detail in the spatial distribution and the spectrum of the hot interstellar gas. Here we describe a few prominent characteristics of the diffuse emission from this region. The diffuse X-ray emission apparently occupying most of the volume within one parsec of the center appears to be partially density bounded on the outside by the dense circumnuclear disk located between 1 and ∼5 pc. Further out, on a scale of ∼10 pc, the diffuse emission is dominated by bipolar X-ray lobes which appear to be centered on the central black hole and oriented perpendicular to the Galactic plane. Within the bipolar lobes are several blobs of X-ray emitting gas which display a rough point reflection symmetry about the center and which are thus consistent with a succession of collimated ejections of hot gas from the immediate vicinity of the black hole. Nonthermal emission from a few places around the rim of the northern lobe of this structure indicates that highly relativistic particles are present in the otherwise apparently thermally emitting lobes.