Spectra and Statistics of Cosmic String Perturbations on the Microwave Background: A Monte Carlo Approach

Abstract

Using Monte Carlo simulations of perturbations induced by cosmic strings on the microwave background, we demonstrate the scale invariance of string fluctuation patterns. By comparing string-induced fluctuation patterns with gaussian random phase ones, we show that the non-gaussian signatures of the string patterns are detectable by tests based on the moments of the distributions only for angular scales smaller than a few arcminutes and for maps based on the gradient of temperature fluctuations. However, we find that tests of the gaussianity of the moments fail when we include a reasonable amount of instrumental noise in a pattern. Signal to noise ratios of $3.3$ or greater completely suppress a string pattern's non-gaussian features even at the highest resolutions.