Probing non-Gaussianities in the CMB on an incomplete sky using surrogates
Abstract
We demonstrate the feasibility to generate surrogates by Fourier-based methods for an incomplete data set. This is performed for the case of a CMB analysis, where astrophysical foreground emission, mainly present in the Galactic plane, is a major challenge. The shuffling of the Fourier phases for generating surrogates is now enabled by transforming the spherical harmonics into a new set of basis functions that are orthonormal on the cut sky. The results show that non-Gaussianities and hemispherical asymmetries in the CMB as identified in several former investigations, can still be detected even when the complete Galactic plane (|b| < 30{\deg}) is removed. We conclude that the Galactic plane cannot be the dominant source for these anomalies. The results point towards a violation of statistical isotropy.
Cite
@article{arxiv.1207.3235,
title = {Probing non-Gaussianities in the CMB on an incomplete sky using surrogates},
author = {G. Rossmanith and H. Modest and C. Räth and A. J. Banday and K. M. Gorski and G. Morfill},
journal= {arXiv preprint arXiv:1207.3235},
year = {2015}
}
Comments
9 pages, 13 figures, accepted by Physical Review D