| Abstract | Results of a neutral hydrogen 21-cm line study of 40 Sa spiral galaxies with apparent magnitudes from 10.5 to 14.5, recession velocities lower than 6500 km/s and intrinsic luminosities from 1 to 40 x 10 to the 9th solar units are presented. The galaxies are found to form a rather homogeneous class, with a relative H I content smaller than that of later spirals and an indicative total mass to luminosity ratio higher than that of later galaxies of the same luminosity. The indicative total mass is also observed to be well correlated to the luminosity, allowing it to be used as a sensitive distance criterion. A linear correlation between the log of the internal velocity spread and the log of the luminosity is obtained; internal velocity spread is also found to depend on galaxy type. Finally, it is observed that the Sa spirals are on the mean five times richer in hydrogen than the hydrogen-rich ellipticals and at least ten times richer than hydrogen-poor ellipticals, supporting the distinction between the two types of elliptical galaxies. |
