| Abstract | Neutral hydrogen observations of 44 nearby galaxies are presented. This project was undertaken in order to search for extended H I haloes. Also it is possible from these data to investigate the effects of incomplete mapping on derived parameters. The derived H I mass is a relatively strong function of the completeness of the mapping, whereas the line width seems to be a rather independent parameter, as long as the dynamically important part of the galaxy is sufficiently covered. This also applies to spot observations of the central position of a galaxy (central profile), as long as the antenna beam covers the galaxy adequately, which is the case for the present sample (optical diameter to antenna beam less than 2.3). The dwarf galaxy, DDO 154, was found to have a particularly extended H I envelope. |
