A Morphology-Cosmology Connection for X-Ray Clusters

We employ N-body/three-dimensional gasdynamic simulations of the formation of galaxy clusters to determine whether cluster X-ray morphologies can be used as cosmological constraints. Confirming the analytic expectations of Richstone, Loeb, (2) an unbiased universe dominated by vacuum energy with OMEGA₀_ = 0. 2 and λ₀_ = 0. 8 and (3) a biased Einstein-de Sitter model (OMEGA = 1, as = 0. 59). Using measures of X-ray morphology such as the axial ratio and centroid shifting, we demonstrate that clusters evolved in the two low OMEGA₀_ models are much more regular, spherically symmetric, and centrally condensed than clusters evolved in the Einstein-de Sitter model. This morphology-cosmology connection, along with the availability of a large body of cluster X-ray observations, makes cluster X-ray morphology both a and a practical cosmological discriminant.