Testing large-angle deviation from Gaussianity in CMB maps

TL;DR

This paper discusses the development and application of two new large-angle non-Gaussianity indicators to analyze CMB maps, aiming to identify deviations from Gaussianity that could inform inflationary models.

Contribution

The paper introduces two novel large-angle non-Gaussianity indicators and applies them to WMAP data to analyze potential non-Gaussian features.

Findings

Indicators detect deviations from Gaussianity on large scales.

Analysis of WMAP maps reveals potential non-Gaussian features.

Results help distinguish primordial from non-primordial non-Gaussianity.

Abstract

A detection of the level of non-Gaussianity in the CMB data is essential to discriminate among inflationary models and also to test alternative primordial scenarios. However, the extraction of primordial non-Gaussianity is a difficult endeavor since several effects of non-primordial nature can produce non-Gaussianity. On the other hand, different statistical tools can in principle provide information about distinct forms of non-Gaussianity. Thus, any single statistical estimator cannot be sensitive to all possible forms of non-Gaussianity. In this context, to shed some light in the potential sources of deviation from Gaussianity in CMB data it is important to use different statistical indicators. In a recent paper we proposed two new large-angle non-Gaussianity indicators which provide measures of the departure from Gaussianity on large angular scales. We used these indicators to carry out analyses of non-Gaussianity of the bands and of the foreground-reduced WMAP maps with and without the KQ75 mask. Here we briefly review the formulation of the non-Gaussianity indicators, and discuss the analyses made by using our indicators.