HI gas disks in elliptical galaxies

Abstract

We discuss a class of low-luminosity E/S0 galaxies which have both HI disks and (in contrast to more luminous E/S0s with HI) ongoing star formation. We suggest that such objects are common, but that only a few are known at present because optical magnitude-limited galaxy catalogues are biased against them. The HI Parkes All-Sky Survey (HIPASS) should eventually detect many more. We suggest that `boxy' and `disky' ellipticals are distinct not only in their structure and kinematics, but in their star-formation history.