Abstract:
CCD images and color index maps of 22 galaxies from the Catalog of Southern Ringed Galaxies (CSRG) are used to examine distinct categories of the morphology of outer rings and pseudorings in SB and SAB galaxies, which bear a remarkable resemblance to the gaseous rings which developed near the outer Lindblad resonance in n-body models of barred spirals. In a class of rings where the arms wind about 180 deg with respect to the ends of a bar or oval, nine out of 11 examples display blue nuclei or circumnuclear rings in a B-I color index map. This contrasts with a class where the arms wind about 270 deg with respect to the ends of a bar or oval, for which only 3 out of 11 examples display nuclear star formation. A similar correlation regarding the presence or absence of a clear dust lane pattern is found within the region of a bar or inner oval. Images of eight additional CSRG galaxies which display morphological details of special interest are presented.
