507 research outputs found

    CMBFAST for spatially closed universes

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    We extend the cosmological linear perturbation theory code CMBFAST to closed geometries. This completes the implementation of CMBFAST to all types of geometries and allows the user to perform an unlimited search in the parameter space of models. This will be specially useful for placing confidence limits on cosmological parameters from existing and future data. We discuss some of the technical issues regarding the implementation.Comment: 6 pages, 2 figures, new version of CMBFAST can be found http://www.sns.ias.edu/~matiasz/CMBFAST/cmbfast.htm

    Extended self-similarity of the small-scale cosmic microwave background anisotropy

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    The Extended Self-Similarity (ESS) of cosmic microwave background (CMB) radiation has been studied using recent data obtained by the space-craft based Wilkinson Microwave Anisotropy Probe. Using the ESS and the high angular scale resolution (arcminutes) of the data it is shown that the CMB temperature space {\it increments} exhibit considerable and systematic declination from Gaussianity for high order moments at the small angular scales. Moreover, the CMB space increment ESS exponents have remarkably close values to the ESS exponents observed in turbulence (in magnetohydrodynamic turbulence)

    Gravitational Lensing of the Microwave Background by Galaxy Clusters

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    Galaxy clusters will distort the pattern of temperature anisotropies in the microwave background via gravitational lensing. We create lensed microwave background maps using clusters drawn from numerical cosmological simulations. A distinctive dipole-like temperature fluctuation pattern is formed aligned with the underlying microwave temperature gradient. For a massive cluster, the characteristic angular size of the temperature distortion is a few arcminutes and the characteristic amplitude a few micro-Kelvin. We demonstrate a simple technique for estimating the lensing deflection induced by the cluster; microwave background lensing measurements have the potential to determine the mass distribution for some clusters with good accuracy on angular scales up to a few arcminutes. Future high-resolution and high-sensitivity microwave background maps will have the capability to detect lensing by clusters; we discuss various systematic limitations on probing cluster masses using this technique.Comment: 8 pages, 8 figures. Expanded discussion of systematic errors and kSZ effect, including new figure; version accepted by Ap
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