Two-dimensional spectral estimators of statistical anisotropy and search for the isolated directions in Planck mission data

Abstract

We describe a method for the analysis of homogeneity of the microwave background maps based on the behavior of the angular power spectrum C(ℓ) and parity parameter P. The estimator is built using the dispersion variation of the power spectrum of the background signal hemisphere and allows to visualize the statistical anisotropy as a new map which characterizes the homogeneity/heterogeneity of the background in the second order. Using the proposed method, we made the data analysis of the WMAP mission nine-year observations and the first Planck mission data release for the map with the resolution of ℓ ≤ 100. As a result, we have detected the asymmetry of the microwave background signal map associated with the ecliptic coordinate system both in the plane of the ecliptic and in the orthogonal direction. We also discuss the problems of generating the anisotropic signal.