We use an optimal estimator to study the variance of the WMAP 9 CMB field at low resolution, in both temperature and polarization. Employing realistic Monte Carlo simulation, we find statistically significant deviations from the ΛCDM model in several sky cuts for the temperature field. For the considered masks in this analysis, which cover at least the 54% of the sky, the WMAP 9 CMB sky and ΛCDM are incompatible at ≥99.94 C.L. at large angles (>5∘). We find instead no anomaly in polarization. As a byproduct of our analysis, we present new, optimal estimates of the WMAP 9 CMB angular power spectra from the WMAP 9 year data at low resolution.
@article{arxiv.1304.5493,
title = {Low Variance at large scales of WMAP 9 year data},
author = {A. Gruppuso and P. Natoli and F. Paci and F. Finelli and D. Molinari and A. De Rosa and N. Mandolesi},
journal= {arXiv preprint arXiv:1304.5493},
year = {2015}
}
Comments
18 pages, 12 figures, 3 tables. Accepted for publication in JCAP