NICMOS observations of the nucleus of Centaurus A

Session 25 - Seyfert Galaxies.
Oral session, Wednesday, January 07
Georgetown,

[25.08] NICMOS observations of the nucleus of Centaurus A

A. Marconi, E. J. Schreier, D. J. Axon, N. Caon, F. D. Macchetto (STScI)

We have obtained HST WFPC2 and NICMOS observations in the nuclear region of the closest powerful active galaxy known, NGC 5128 (Centaurus A). Narrow band imaging in the Pa\alpha line shows an elongated structure around the nucleus which we interpret as a disk of ionized gas, with a 15 pc radius. The disk does not appear to be perpendicular to the Radio/X-ray jet and shows features resembling a spiral arm. In the nuclear region we also detect bow-shock like emission knots part of which are associated with the N1 knot discovered with VLA observations and whose relationship with the jet has always been uncertain. The K band continuum image shows the rather regular and smooth structure typical of the nucleus of an elliptical galaxy.

Program listing for Wednesday