Centaurus A: Molecular gas shells or large-scale outflow?^*

¹ Onsala Space Observatory, Chalmers University of Technology, 439 92 Onsala, Sweden
² School of Physics, University of New South Wales, Sydney NSW 2052, Australia
³ European Southern Observatory, Casilla 19001, Santiago 19, Chile

Received: 2 May 2001
Accepted: 6 July 2001

Abstract

In order to test if the molecular "shells" observed by Charmandaris et al. ([CITE]) could be due to a molecular outflow, we have mapped CO in and along the jet axis of Centaurus A. Where our map coincides with their observed positions, like them, we obtain detections with a similar antenna temperature for CO , although both transitions appear to be somewhat wider in velocity dispersion than theirs. As well as these, we have several tentative detections at distances of 5 kpc from the nucleus, and although these results are of too poor quality in order to verify or refute the shell model in favour of a molecular outflow, our observations of the inner kpc do suggest that at least a small-scale outflow is a possibility. Whether this would be a component of a larger-scale outflow or exists in conjunction with the molecular gas shells will have to wait for a much more extensive mapping of the large-scale gas distribution in Centaurus A, for which these and the results of Charmandaris et al. ([CITE]) will hopefully provide sufficient motivation.