X-ray arc structures in Chandra images of NGC 5128 (Centaurus A)

We describe results from our initial study of the diffuse X-ray emission structures in NGC 5128 (Centaurus A) using the Chandra X-ray Observatory observations. The high angular resolution Chandra images reveal multiscale X-ray structures with unprecedented detail and clarity. The large-scale structures suggest complex symmetry, including a component possibly associated with the inner radio lobes, and a separate component with an orthogonal symmetry that may be associated with the galaxy as a whole. We detect arclike soft X-ray structures, extending to similar to8 kpc in the direction perpendicular to the jet. These arcs appear to be tracing an ellipse, or a ring seen in projection, and are enclosed between the dust and H I-emitting gas in the central region of the galaxy and the optical and H I shell fragments at a distance of about 8 10 kpc. The diffuse X-ray and the optical emission in the arcs could originate in a region of interaction ( possibly a shock) between the infalling material from the outer regions of the galaxy and the cool dust and H I-emitting material in the center or from an equatorial outflow resulting from an outburst of nuclear activity similar to10(7) yr ago.