Application of Contour Minkowski Tensor and $\mathcal{D}$ Statistic to the Planck $E$-mode data

TL;DR

This paper assesses the statistical isotropy of Planck satellite's CMB E-mode polarization data using contour Minkowski Tensor and $\,\mathcal{D}$ statistic, finding consistency with simulations and supporting isotropy.

Contribution

It introduces the application of the $\,\alpha$ estimator from contour Minkowski Tensor and $\,\mathcal{D}$ statistic to analyze Planck CMB E-mode data for isotropy.

Findings

Good agreement between Planck data and simulations for both statistics.

Supports the statistical isotropy of the CMB E-mode polarization.

Validates the effectiveness of the $\,\alpha$ and $\,\mathcal{D}$ statistics in CMB analysis.

Abstract

We test the statistical isotropy (SI) of the $E$-mode polarization of the Cosmic Microwave Background (CMB) radiation observed by the Planck satellite using two statistics, namely, the $\alpha$ estimator that is derived from the contour Minkowski Tensor (CMT), and the Directional statistic ($\mathcal{D}$ statistic). The $\alpha$ estimator obtained from the CMT provides information about the alignment of structures and can be used to infer statistical properties such as Gaussianity and SI of random fields. The $\mathcal{D}$ statistic is based on detecting preferred directionality shown by vectors defined by the field. We compute $\alpha$ and $\mathcal{D}$ statistic for the low resolution component separated SMICA $E$-mode map of CMB polarization, and compare with the values calculated using FFP10 SMICA simulations. We find good agreement between the Planck data and SMICA simulations for both $\alpha$ estimator and $\mathcal{D}$ statistic.