| Abstract | A large sample of S0 galaxies was observed with the 305-m Arecibo telescope in both the 21-cm neutral-hydrogen line and the 21-cm continuum to test the hypothesis that weak bursts of star formation are a relevant factor in the evolution of such galaxies. Results are presented which indicate that the ratio between the neutral-hydrogen mass and B luminosity, M(HI)/L(B), of S0 galaxies ranges over at least a factor of 50, that all true S0's have M(HI)/L(B) ratios of less than 0.1, and that there are apparently no significant differences in M(HI)/L(B) among the three defined S0 subclasses. The results obtained are compared with theoretical calculations as well as with observational data on normal spirals and Markarian galaxies. The M(HI)/L(B) ratios and colors observed for the S0 galaxies are shown to be consistent with the suggestion that weak bursts of star formation occur in these galaxies and may account completely for their observed low neutral-hydrogen contents. |
