HI IN SHELL GALAXIES AND OTHER MERGER REMNANTS

The few elliptical galaxies with detected HI almost all seem to have o ptical peculiarities as well, though these are often well hidden and r equire special image enhancement techniques to reveal them. In this pa per we show several deep images of ellipticals with optical shells whi ch are associated with HI, and suggest that mergers, or at least encou nters with gas-rich galaxies, are responsible. We also show some disk galaxies with unusual faint extensions, some of them the kinds of inte ractions that may result in HI in ellipticals. These illustrations are drawn from an atlas of low surface brightness images of bright galaxi es currently in preparation.