Statistical Power, the Bispectrum and the Search for Non-Gaussianity in the CMB Anisotropy

Abstract

We use simulated maps of the cosmic microwave background anisotropy to quantify the ability of different statistical tests to discriminate between Gaussian and non-Gaussian models. Despite the central limit theorem on large angular scales, both the genus and extrema correlation are able to discriminate between Gaussian models and a semi-analytic texture model selected as a physically motivated non-Gaussian model. When run on the COBE 4-year CMB maps, both tests prefer the Gaussian model. Although the bispectrum has comparable statistical power when computed on the full sky, once a Galactic cut is imposed on the data the bispectrum loses the ability to discriminate between models. Off-diagonal elements of the bispectrum are comparable to the diagonal elements for the non-Gaussian texture model and must be included to obtain maximum statistical power.

Accepted for publication in ApJ; 20 pages, 6 figures, uses AASTeX v5.0

References in corpus (3)

• On the Non-Gaussianity Observed in the COBE-DMR Sky Maps
• New non-Gaussian feature in COBE-DMR Four Year Maps
• Do wavelets really detect non-Gaussianity in the 4-year COBE data?

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