A Study of Gaussianity in CMB band maps

TL;DR

This paper investigates the Gaussianity of CMB band maps using new indicators, finding significant deviations in full-sky maps that diminish when applying a mask, thus aiding in understanding primordial non-Gaussianity.

Contribution

The study extends previous work by applying novel non-Gaussianity indicators to foreground-reduced CMB maps, demonstrating the impact of masking on Gaussianity detection.

Findings

Significant non-Gaussianity in full-sky CMB maps.

Masking reduces non-Gaussianity to levels consistent with Gaussianity.

New indicators effectively detect deviations from Gaussianity.

Abstract

The detection of non-Gaussianity in the CMB data would rule out a number of inflationary models. A null detection of non-Gaussianity, instead, would exclude alternative models for the early universe. Thus, a detection or non-detection of primordial non-Gaussianity in the CMB data is crucial to discriminate among inflationary models, and to test alternative scenarios. However, there are various non-cosmological sources of non-Gaussianity. This makes important to employ different indicators in order to detect distinct forms of non-Gaussianity in CMB data. Recently, we proposed two new indicators to measure deviation from Gaussianity on large angular scales, and used them to study the Gaussianity of the raw band WMAP maps with and without the KQ75 mask. Here we extend this work by using these indicators to perform similar analyses of deviation from Gaussianity of the foreground-reduced Q, V, and W band maps. We show that there is a significant deviation from Gaussianity in the considered full-sky maps, which is reduced to a level consistent with Gaussianity when the KQ75 mask is employed.