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Discovery of a nuclear gas bar feeding the active nucleus in Circinus

R. Maiolino·A. Alonso-Herrero·S. Anders·A. Quillen·M. J. Rieke·G. H. Rieke·L. E. Tacconi-Garman
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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.

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R. Maiolino, A. Alonso-Herrero, S. Anders, A. Quillen, M. J. Rieke, G. H. Rieke, L. E. Tacconi-Garman. 1999-10-08. Discovery of a nuclear gas bar feeding the active nucleus in Circinus. https://doi.org/10.1086/308444

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