Abstract
I have detected 21 cm line emission from neutral hydrogen in the giant elliptical galaxy NGC 807 at Arecibo Observatory, and I have mapped this emission with the VLA. Unlike the active and dwarf ellipticals that have been mapped thus far, NGC 807 has a fairly regular disk of gas rotating about the apparent optical minor axis. Combined with observations of active ellipticals, this observation suggests that two classes of HI-rich ellipticals may exist: ellipticals which have accreted gas and become active recently, and quiescent ellipticals which have either produced gas internally or accreted it so long ago that it has reached dynamical equilibrium.
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