The inner radio structure of Centaurus A : clues to the origin of thejet X-ray emission.

Multifrequency (1.4 and 4.9 GHz) observations of the jet and inner lobes of the nearby radio galaxy Centaurus A (= NGC 5128) were made with the VLA. These data were used to construct maps of the total intensity and polarization at resolutions of 31arcsec×10arcsec and 3arcsec.6×1arcsec.1. The distributions of surface brightness and pressure in the jet combined with the apparent X-ray emission from the ISM of NGC 5128 indicate that the radio jet is thermally confined. A comparison of the radio structure and the optical galaxy shows that the jet in Cen A emerges nearly along the major axis of the elliptical stellar component which is parallel to the angular momentum vector of the dust lane. A detailed comparison of the X-ray and radio emission in the jet demonstrates that the knots coincide precisely at the two energies. This fact argues in favor of a common synchrotron radiation origin for the full spectrum jet emission. The implications of X-ray synchrotron radiation from γ = 8×10⁷ electrons on models of in situ particle acceleration are briefly considered.