Where Centaurus A gets its X-ray knottiness

Worrall, D.M.; Birkinshaw, M.; Kraft, R.P.; Sivakoff, G.R.; Jordan, A.; Hardcastle, M.J.; Brassington, Nicola; Croston, J.H.; Evans, D.A.; Forman, W.R.; Harris, W.E.; Jones, C.; Juett, A.M.; Murray, S.S.; Nulsen, P.E.J.; Raychaudhury, S.; Sarazin, C.L.; Woodley, K.A.

Author

Worrall, D.M.

Birkinshaw, M.

Kraft, R.P.

Sivakoff, G.R.

Jordan, A.

Hardcastle, M.J.

Brassington, Nicola

Croston, J.H.

Evans, D.A.

Forman, W.R.

Harris, W.E.

Jones, C.

Juett, A.M.

Murray, S.S.

Nulsen, P.E.J.

Raychaudhury, S.

Sarazin, C.L.

Woodley, K.A.

Abstract

We report an X-ray spectral study of the transverse structure of the Centaurus A jet using new data from the Chandra Cen A Very Large Project. We find that the spectrum steepens with increasing distance from the jet axis, and that this steepening can be attributed to a change in the average spectrum of the knotty emission. Such a trend is unexpected if the knots are predominantly a surface feature residing in a shear layer between faster and slower flows. We suggest that the spectral steepening of the knot emission as a function of distance from the jet axis is due to knot migration, implying a component of transverse motion of knots within the flow.