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Session 52 - Simulations of Clusters of Galaxies.
Display session, Tuesday, January 16
North Banquet Hall, Convention Center

[52.01] Testing the Cosmological Implications of the X-ray Substructure in Clusters of Galaxies

I. R. Walker, L. Hernquist, G. Blumenthal (UC Santa Cruz)

In an Ømega=1 universe, the growth of structure continues indefinitely, building up larger and larger structures. If Ømega_0<1, the universe reaches a point where its expansion separates the growing structures too rapidly for them to continue to fall together. What structure has already formed evolves in isolation thereafter and eventually becomes smooth and dynamically relaxed. The hot gas in clusters offers a continuous tracer of the cluster potential and X-ray observations have revealed significant substructure in this gas. If this represents dynamical youth, it can be used to place a lower limit on Ømega_0.

This argument is delightfully simple but needs to be quantified to be useful. We will report on simulations of clusters in various cosmologies performed with a hybrid N-body/hydro code to follow the coupled evolution of the gas and dark matter. This allows us to determine the lengthscale, amplitude, longevity, and frequency of the substructure in the gas and the dependence of these characteristics on the cosmological model.

Program listing for Tuesday