Statistical Tests for Non-Gaussianity in the COBE DMR Four-Year Sky Maps

Abstract

In this report we examine the role statistics play in the search for possible non-Gaussianities within the cosmic microwave background. The theoretical basis for a Gaussian distribution is discussed as well as models which predict alternative behaviour. We construct a Monte Carlo simulation of the CMB in real space and compare various moments and cumulants of different sized data sets with the four-year COBE-DMR data. Due to limitations in our simulation regarding correlation between nearest-neighbour pixels and non-independence of individual statistical values, we are unable to provide evidence for or against Gaussianity. However, the effects of bad simulation are qualitatively discussed and ideas for improving the technique are put forward.

Subject headings: Cosmology: cosmic microwave background, Methods: data analysis, statistical

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