in a Gaussian sky is only 1.4%. Such non-Gaussian features are reduced as the higher Galactic cut is applied, but their dependence on the Galactic cut is weak. We discuss possible sources that can induce such non-Gaussian features, such as the Galactic foregrounds, the Integrated Sachs-Wolfe and the Sunyaev-Zel’dovich effects, and the reionisation-induced low $\ell$-mode non-Gaussianity that are aligned along the Galactic plane. We conclude that the CMB data with higher signal-to-noise ratio and the accurate foreground model are needed to understand the non-Gaussian signatures.'
title: 'Non-Gaussian Signatures in the Temperature Fluctuation Observed by the Wilkinson Microwave Anisotropy Probe'
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cosmology – cosmic microwave background

Introduction
============

Recently the Wilkinson Microwave Anisotropy Probe[^1] (WMAP) satellite mission has opened a new door to the precision cosmology. The WMAP has measured the cosmic microwave background (CMB) temperature anisotropy and polarisation with high resolution and sensitivity (Bennett et al. 2003a). The WMAP data implies that the observed CMB fluctuations are consistent with predictions of the concordance $\Lambda$CDM model with scale-invariant and adiabatic fluctuations which have been generated during the inflationary epoch (Hinshaw et al. 2003; Kogut et al. 2003; Spergel et al. 2003; Page et al. 2003; Peiris et al. 2003).

An 