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J.O. Burns (University of Colorado, Boulder), P.M. Motl (Louisiana State University), M.L. Norman (University of California, San Diego), E.J. Hallman (University of Colorado, Boulder)
We critically analyze the role of clusters of galaxies as probes for precision cosmology. Using synthetic observations of simulated clusters viewed through their X-ray emission and thermal Sunyaev-Zeldovich effect (SZE), we reduce the observations to attain measurements of the cluster gas mass and the Hubble constant. We utilize both parametric models such as the isothermal cluster model (and its generalizations to account for varying temperature profiles within the clusters) and non-parametric models that involve the geometric deprojection of the cluster emission assuming spherical symmetry. We are thus able to quantify the possible sources of uncertainty and systematic bias associated with the common simplifying assumptions used in reducing real cluster observations including isothermality and hydrostatic equilibrium. As a specific example, we find that the standard isothermal cluster model yields estimates of the Hubble constant that are systematically biased to low values. When we allow the temperature to vary in space, as in the polytropic cluster model, the X-ray and thermal SZE observations can be combined to produce an unbiased estimator of H0.
The author(s) of this abstract have provided an email address for comments about the abstract: hallman@casa.colorado.edu
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.