Evolution of galaxy clusters in $\Lambda$MDM cosmologies

Abstract

The time evolution of galaxy cluster abundance is used to constrain cosmological parameters in dark matter models containing a fraction of hot particles (massive neutrino). We test the modified MDM models with cosmic gravitational waves which are in agreement with observational data at $z=0$, and show that they do not pass the cluster evolution test and therefore should be ruled out. The models with a non-zero cosmological constant are in better agreement with the evolution test. We estimate ${\Omega }_{\Lambda }$ and find that it is strongly affected by a small fraction of hot dark matter: $0.4<{\Omega }_{\Lambda }<0.8$ for ${\Omega }_H/{\Omega }_M<0.2$.

9 pages, 12 figures included; to be published in Proceedings of XXXVIth Rencontres de Moriond "Galaxy clusters and the high-redshift Universe observed in X-rays" (Les Arcs, France, March 10-17, 2001)