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Session 102 - Clusters of Galaxies.
Display session, Thursday, January 16
We perform a series of N-body experiments to determine whether sub-structure in galaxy clusters is a long lasting effect, or simply a short lived stage in the evolution of a cluster. From simulations of 128^3 particles we extract groups of particles using a friends-of-a-friend algorithm which we take as our clusters. Using a variety of statistical methods first described by Bird (1994) we find that the final evolved state of the clusters all exhibit sub-structure, regardless of spectral index and the value of Ømega_0. We find a small difference in the abundance of sub-structure between critical density models and low density models, and conclude that based upon the low resolution models sub-structure is not a useful diagnostic of the cosmological initial conditions.
To check for the existence of particle discreteness effects we apply the Nested-Grid Particle Mesh code of Splinter (1996) to a subset of the original clusters. Using this code with its higher force and mass resolution we will be able to make definitive statements regarding the existence of substructure.
Program listing for Thursday