A comparative study of non-Gaussianity in ILC-7yr CMB map

TL;DR

This paper compares two statistical methods based on skewness and kurtosis for detecting primordial non-Gaussianity in the WMAP 7-year CMB map, finding the spherical cells method more sensitive.

Contribution

It provides a comparative analysis of two new NG detection methods, highlighting the higher sensitivity of the spherical cells approach.

Findings

Spherical cells detect higher NG levels than overlapping caps.

The study emphasizes the importance of method choice in NG detection.

Results suggest different estimators have varying sensitivities to NG signals.

Abstract

A detection or non detection of primordial non--Gaussianity (NG) by using the cosmic microwave background radiation (CMB) is a possible way to break the degeneracy of early universe models. Since a single statistical estimator hardly can be sensitive to all possible forms of NG which may be present in the data, it is important to use different statistical estimators to study NG in CMB. Recently, two new large-angle NG indicators based on skewness and kurtosis of spherical caps or spherical cells of CMB sky have been proposed and used in both CMB data and simulated maps. Here, we make a comparative study of these two different procedures by examining the NG in the WMAP seven years ILC map. We show that the spherical cells procedure detects a higher level of NG than that obtained by the method with overlapping spherical caps.