Non-gaussianity in the HILC foreground-reduced three-year WMAP CMB map

摘要

The detection or non-detection of primordial non-Gaussianity in the CMB data is essential not only to test alternative models of the physics of the early universe but also to discriminate among classes of inflationary models. Given this far-reaching consequences of such a non-Gaussianity detection for our understanding of the physics of the early universe, it is important to employ alternative indicators in order to have further information about the Gaussianity features of CMB that may be helpful for identifying their origins. In this way, a considerable effort has recently gone into the design of non-Gaussianity indicators, and in their application in the search for deviation from Gaussianity in the CMB data. Recently we have proposed two new large-angle non-Gaussianity indicators which provide measures of the departure from Gaussianity on large angular scales. We have used these indicators to carry out analyses of Gaussianity of the single frequency bands and of the available foreground-reduced five-year maps with and without the KQ75 mask. Here we extend and complement these studies by performing a new analysis of deviation from Gaussianity of the three-year harmonic ILC (HILC) foreground-reduced full-sky and KQ75 masked maps obtained from WMAP data. We show that these full-sky foreground-reduced maps present a significant deviation from Gaussianity, which is brought down to a level of consistency with Gaussianity when the KQ75 mask is employed.