| Abstract | The authors have obtained 21-cm H I observations of a sample of 32 dwarf irregular (dI) and 12 dwarf elliptical (dE) galaxies that are located in the Virgo cluster. Altogether, 18 of 32 dIs were detected in H I, but none of the dEs were detected at a sensitivity level of MHI = 2 - 3×106M_sun;. The detected dIs have MHI > 3×107M_sun;. This disparity in H I content between dIs and dEs effectively dispels the possibility that the dEs are presently in a stage of quiescence (hibernation), between bursts of star formation. In order to supplement the 21-cm data, the authors have acquired optical spectroscopy, CCD images, and infrared photometry for a limited subsample of these dwarfs. They discuss the general H I, infrared, and dynamical properties of the dwarfs and show how these properties relate to the hypothesis previously outlined, namely that dEs may be stripped dIs. |
