X‐Ray Arc Structures inChandraImages of NGC 5128 (Centaurus A)

We describe results from our initial study of the diffuse X-ray emissionstructures in NGC 5128 (Cen A) using the Chandra X-ray Observatoryobservations. The high-angular resolution Chandra images reveal multi-scaleX-ray struct ures with unprecedented detail and clarity. The large scalestructures suggest complex symmetry, including a component possibly associatedwith the inner radio lobes, and a separate component with an orthogonalsymmetry that may be associated with the galaxy as a whole. We detect arc-likesoft X-ray structures, extending to ~8 kpc in the direction perpendicular tothe jet. These arcs appear to be tracing an ellipse, or a ring seen inprojection, and ar e enclosed between the dust and HI emitting gas in thecentral region of the galaxy, and the optical and HI shell fragments at adistance of about 8-10 kpc. The diffuse X-ray and the optical emission in thearcs could originate in a region of interaction (possibly a shock) between theinfalling material from the outer regions of the galaxy, and the cool dust andHI emitting material in the center, or an equatorial outflow resulting from anoutburst of nuclear activity ~10^7 years ago.Comment: 8 pages, three color figures, to be published in ApJ September 20, 2002 issu