ar X iv : a st ro - p h / 95 12 04 3 v 1 7 D ec 1 99 5 Neutral Hydrogen in the Ringed Barred Galaxies NGC 1433 and NGC 6300 1

We have made observations of the H I in the southern ringed barred spiral galaxies NGC 1433 and NGC 6300 with the Australia Telescope Compact Array (ATCA), the main goal being to test the resonance theory for the origin of these rings. NGC 1433 is the prototypical ringed barred spiral, and displays distinct H I counterparts to its nuclear ring, inner ring, outer pseudoring, and plume-like features. The L4 and L5 regions at corotation, as well as the bar itself, are relatively devoid of neutral atomic hydrogen. We use the Tully-Fisher relation to argue that the mean inclination of the disk of NGC 1433 is closer to 33◦ than to 20◦, meaning that its outer pseudoring is intrinsically almost circular, while the inner ring is rather more elongated than the average (based on results from the Catalog of Southern Ringed Galaxies). Strong radio continuum emission is localized to the nucleus and the ends of the bar in NGC 1433, and we place an upper limit on the 1.38 GHz flux of the Type II SN 1985P a decade after the explosion. By associating the inner ring of NGC 1433 with the inner second harmonic resonance, and its outer pseudoring with the outer Lindblad resonance, we are able to infer a bar pattern speed for NGC 1433 of 26± 5 km s kpc. Based on observations made with the Australia Telescope Compact Array, which is operated by CSIRO Australia Telescope National Facility. Current address: School of Physics, University of New South Wales, Sydney 2052, Australia. Also at Instituto de Astronomia-UNAM, México.