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Session 85 - Cosmology: Observations.
Display session, Friday, January 09
Exhibit Hall,

[85.06] Measurement of the Cosmological Deceleration Constant from Clusters of Galaxies

R. J. Danos, U. Pen (SAO)

We present the parameters for a hydrostatic-isothermal \beta-model for several Pen (1997) galaxy cluster simulations using five different cosmologies for input parameters. We also present contour maps and radial profiles supporting the Richstone (Richstone, D., Loeb, A., and Turner, E.L. 1992, Apj, 393, 477) analytical models for cluster geometry. The radial profiles of the cluster simulations also support the assumption that clusters are roughly spherically symmetric within the core radius. We present the results of determining the central electron number density and gas fractions for both the Pen (Pen, U. 1996, astrop-ph/9610090) and Evrard (Evrard, A., Metzler, C., Navarro, J. 1996, Apj, 469,494) methods. We apply these methods both to the simulated clusters and to low and high redshift clusters reported in the literature. These values will lead us to the calculation of the angular distance diameter and the deceleration constant, q_0 with errors. Our approach will also be used to calculate these quantities for a model of the universe including the cosmological constant, \Lambda.

Program listing for Friday