Substructure in Clusters as a Cosmological Test

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Session 87 -- Cluster Evolution
Display presentation, Friday, January 14, 9:30-6:45, Salons I/II Room (Crystal Gateway)

[87.04] Substructure in Clusters as a Cosmological Test

Mary M. Crone, August E. Evrard, Douglas O. Richstone (U. of Michigan)

\noindent Once believed to be relaxed systems, clusters of galaxies are now observed to contain substructure. The amount of substructure observed may prove to be a useful cosmological test; clusters form earlier in a less dense universe, and therefore have more time to relax. \vskip 5pt \noindent We have used N-body simulations to quantify the amount of cluster substructure for cosmologies with $\Omega_o = 1.0,\Omega_o = 0.2,\Omega_o = 0.1$, and $\Omega_o = 0.2, \lambda_o = 0.8$ for initial power spectra $P(k) = Ak^n$ with $n = -2, -1, 0$. Tests used to quantify substructure include the Lee-Fitchett and Dressler-Schectman statistics, as well as a shift in the center-of-mass with density cutoff. We find significantly more substructure in the denser universes. How observable these differences are is currently under investigation.

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