DECAYING NEUTRINOS IN GALAXY CLUSTERS

Davidsen et al. (1991) have argued that the failure to detect UV photo ns from the dark matter (DM) in cluster A665 excludes the decaying neu trino hypothesis. Sciama et al. (1993) argued that because of high cen tral concentration the DM in that cluster must be baryonic. We study t he DM profile in clusters of galaxies simulated using the Harrison-Zel 'dovich spectrum of density fluctuations, and an amplitude previously derived from numerical simulations (Melott 1984b; Anninos et al. 1991) and in agreement with microwave background fluctuations (Smoot et al. 1992). We find that with this amplitude normalization cluster neutrin o DM densities are comparable to observed cluster DM values. We conclu de that given this normalization, the cluster DM should be at least la rgely composed of neutrinos. The constraint of Davidsen et al. can be somewhat weakened by the presence of baryonic DM; but it cannot be eli minated given our assumptions.