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Paper: Morphological Evolution of X--ray Clusters Using High--Resolution Hydro--Simulations
Volume: 176, Observational Cosmology: The Development of Galaxy Systems
Page: 163
Authors: Valdarnini, Riccardo; Ghizzardi, Simona; Bonometto, Silvio
Abstract: A large set of TREESPH simulations is used to test the global structure of galaxy clusters and its evolution, through a systematic statistical comparison with available X--ray data. Structure tests are based on the power ratios introduced by Buote & Tsai. We consider flat CDM, L (Ω_Λ = 0.7) and M (Ω_h = 0.2, 1 massive ν), normalized so to provide a fair number density of clusters. For each cosmological model we perform a P3M simulation in a large box and select the volumes where the most massive 40 clusters form. There we run a hydrodynamical TREESPH simulation for each cluster. We used the Student t--test, the F--test and the Kolmogorov--Smirnov test to perform a statistical comparison of the global morphology of clusters, expected in each cosmological model, with ROSAT data. In some of previous analyses, DM distribution, instead of gas, was used; we find that this leads to systematically biased results, as DM distribution is substantially more structured than baryon distribution. We also find different behaviors for the cosmological models considered, in respect to these tests: L has the worst score. CDM and the M mixture considered here have similar performances. A further improvement for the model--data fit is expected either from a different DM mix or a non--flat CDM model.
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