Supernovae and star formation in clusters of galaxies.

An investigation has been conducted in connection with the suggestion that all supernovae, including those in early-type galaxies, are products of recent star formation. If the suggestion is correct and if elliptical and S0 galaxies in the cores of dense clusters are swept of gas by the intracluster medium, it should be expected that the considered galaxies have a lower supernova rate and redder colors than similar galaxies in the field. In the investigation, normal elliptical and S0 galaxies are collectively referred to as EL's. It is shown that the supernova rate in EL's is indeed much lower in the cores of spiral-poor clusters than elsewhere. It is also demonstrated that the expected color differences exist among the EL's.