Low variance at large scales of WMAP 9 year data
Author(s)
Date Issued
2013-07-01
Mission(s)
Other
Abstract
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 LambdaCDM 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 LambdaCDM 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.