| Abstract | Sixteen disk galaxies of early type, detected in a systematic survey, were mapped in neutral hydrogen with the 3.2-arcmin Arecibo beam. More than half of the galaxies have extended neutral hydrogen emission. Hydrogen masses and radii tend to be smaller for galaxies in the Virgo cluster core than outside of it. Galaxies with extended emission satisfy a 'Tully-Fisher relation' (velocity width versus luminosity) similar to that for late-type spirals. For five galaxies a rotation curve was obtained: three of the curves are flat, and two appear similar to that of M81. Mass-to-luminosity ratios estimated for these five cases are also similar to those for spirals. For at least two galaxies (possibly four) the 21 cm line has a very narrow profile, and the neutral hydrogen must be concentrated in a small region near the nucleus. |
