Discovery of a nuclear gas bar feeding the active nucleus in Circinus
Abstract
We report the discovery of gas inflow motions towards the active nucleus of the Circinus galaxy caused by the non-axisymmetric potential of a nuclear gas bar. Evidence for dust associated with the bar comes from the HST/NICMOS H-K color map, whereas the streaming motions along the gas bar are seen in the velocity field of the H2 S(1)(1-0) emission line. The gas bar is about 100 pc long with a visual extinction in excess of 10 mag. Indication for the gaseous nature of this bar comes from the lack of a stellar counterpart even in the K band where the extinction is greatly reduced. We also use the NICMOS emission line images (Pa-alpha, [SiVI], and [FeII]) to study the innermost region of the ionization cones and the nuclear star forming activity. We discuss the possible relationship of these components with the gaseous bar.
Cite
@article{arxiv.astro-ph/9910160,
title = {Discovery of a nuclear gas bar feeding the active nucleus in Circinus},
author = {R. Maiolino and A. Alonso-Herrero and S. Anders and A. Quillen and M. J. Rieke and G. H. Rieke and L. E. Tacconi-Garman},
journal= {arXiv preprint arXiv:astro-ph/9910160},
year = {2009}
}
Comments
14 pages, 7 figures (3 color plates), accepted for publication in ApJ