Observations of Neutral Hydrogen in Bright Southern Galaxies

Abstract

Neutral hydrogen was detected in 36 out of 46 galaxies observed at 21 cm wavelength. Eighteen of the larger ones were partially mapped, and estimates of hydrogen and total mass obtained. Without correction for optical depth effects, median values of MH and MH/MT were 7·5 X 109 M0 and 0'07 respectively. These values are similar to the average values found previously for Sc-Scd galaxies (the median morphological type for the sample). The lowest MH/MT ratios were found for NGC253 and 4945, probably because of absorption of the nuclear continuum in addition to any hydrogen self-absorption.