Three Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Polarization Analysis
Abstract
The Wilkinson Microwave Anisotropy Probe WMAP has mapped the entire sky in five frequency bands between 23 and 94 GHz with polarization sensitive radiometers. We present three-year full-sky maps of the polarization and analyze them for foreground emission and cosmological implications. These observations open up a new window for understanding the universe. WMAP observes significant levels of polarized foreground emission due to both Galactic synchrotron radiation and thermal dust emission. The least contaminated channel is at 61 GHz. Informed by a model of the Galactic foreground emission, we subtract the foreground emission from the maps. In the foreground corrected maps, for l=2-6, we detect l(l+1) C_l^{EE} / (2 pi) = 0.086 +-0.029 microkelvin^2. This is interpreted as the result of rescattering of the CMB by free electrons released during reionization and corresponds to an optical depth of tau = 0.10 +- 0.03. We see no evidence for B-modes, limiting them to l(l+1) C_l^{BB} / (2 pi) = -0.04 +- 0.03 microkelvin^2. We find that the limit from the polarization signals alone is r<2.2 (95% CL) corresponding to a limit on the cosmic density of gravitational waves of Omega_{GW}h^2 < 5 times 10^{-12}. From the full WMAP analysis, we find r<0.55 (95% CL) corresponding to a limit of Omega_{GW}h^2 < 10^{-12} (95% CL).
Cite
@article{arxiv.astro-ph/0603450,
title = {Three Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Polarization Analysis},
author = {L. Page and G. Hinshaw and E. Komatsu and M. R. Nolta and D. N. Spergel and C. L. Bennett and C. Barnes and R. Bean and O. Doré and J. Dunkley and M. Halpern and R. S. Hill and N. Jarosik and A. Kogut and M. Limon and S. S. Meyer and N. Odegard and H. V. Peiris and G. S. Tucker and L. Verde and J. L. Weiland and E. Wollack and E. L. Wright},
journal= {arXiv preprint arXiv:astro-ph/0603450},
year = {2008}
}
Comments
105 pgs, 28 figs. Accepted version of the 3-year paper as posted to http://lambda.gsfc.nasa.gov/product/map/dr2/map_bibliography.cfm in January 2007