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M. W. Regan (Carnegie Inst. of Washingtion/DTM), J. S. Mulchaey (Obse. of the Carnegie Inst. of Washington)
Galactic bars are frequently invoked as a candidate for facilitating the transfer of mass from the interstellar medium of active galaxies to their central engines. However, the incidence of bars in these active galaxies is no higher than that in quiescent spiral galaxies based on recent ground-based studies of Seyferts. Furthermore, numerical simulations indicate that gas inflow generated by a large-scale stellar bar does not extend down to the scales required to feed the central engine. However, simulations also indicate that a series of nested gaseous bars may form in some cases, driving inflow of gas to the scales where the central blackhole dominates the potential.
We present initial results of a HST NICMOS snapshot survey of a sample of Seyfert and quiescent galaxies which we use to test this "bars-within-bars" model for fueling the nucleus. Only the resolution of NICMOS can reach the size scales needed (10--50 pc) to test the model. We will combine the NICMOS images with existing data to search for small-scale stellar bars and the dust associated with gaseous bars and to search for differences between the active and normal galaxies that might explain the differences in observed activity.