X-ray observations of distant blue clusters of galaxies

X-ray observations are reported for a sample of distant clusters for which the percentage of apparent cluster members that are blue has been determined optically. The X-ray properties of the clusters are not simply related to the optical properties. The X-ray observations do not support models in which blue galaxies change color as a result of ram-pressure stripping, or in which star formation is triggered by interaction with an intracluster medium. The data lend some support to the idea that blue galaxies in distant clusters are being observed immediately after the removal of galactic halos, and before the interstellar medium is depleted (Larson et al., 1980).