Eccentricity Evolution in Simulated Galaxy Clusters

Strong cluster eccentricity evolution for $z\le 0.13$ has appeared in a variety of observational data sets. We examine the evolution of eccentricity in simulated galaxy clusters using a variety of simulation methodologies, amplitude normalizations, and background cosmologies. We do not find find such evolution for $z<0.1$ in any of our simulation ensembles. We suggest a systematic error in the form of a redshift-dependent selection effect in cluster catalogs or missing physics in cluster simulations important enough to modify the cluster morphology.