A high-significance detection of non-Gaussianity in theWMAP5-yr data using directional spherical wavelets

Abstract

We repeat the directional spherical real Morlet wavelet analysis, used previously to detect non-Gaussianity in the Wilkinson Microwave Anisotropy Probe (WMAP) 1- and 3-yr data, on the WMAP 5-yr data. The non-Gaussian signal detected previously is present in the 5-yr data at a slightly increased statistical significance of approximately 99 per cent. Localized regions that contribute most strongly to the non-Gaussian signal are found to be very similar to those detected in the previous releases of the WMAP data. When the localized regions detected in the 5-yr data are excluded from the analysis, the non-Gaussian signal is eliminated.