Li, Chao and Smith, Tristan L. and Cooray, Asantha (2007) Non-Gaussian covariance of CMB B modes of polarization and parameter degradation. Physical Review D, 75 (8). Art. No. 083501. ISSN 0556-2821. http://resolver.caltech.edu/CaltechAUTHORS:LICprd07a
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The B-mode polarization lensing signal is a useful probe of the neutrino mass and to a lesser extent the dark energy equation of state as the signal depends on the integrated mass power spectrum between us and the last scattering surface. This lensing B-mode signal, however, is non-Gaussian and the resulting non-Gaussian covariance to the power spectrum could impact cosmological parameter measurements, as correlations between B-mode bins are at a level of 0.1. On the other hand, for temperature and E-mode polarization power spectra, the non-Gaussian covariance is not significant, where we find correlations at the 10-5 level even for adjacent bins. When the power spectrum is estimated with roughly 5 uniformly spaced bins from l=5 to l=100 and 13 logarithmic uniformly spaced bins from l=100 to l=2000, the resulting degradation on neutrino mass and dark energy equation of state is about a factor of 2 to 3 when compared to the case where statistics are simply considered to be Gaussian. If we increase the total number of bins between l=5 and l=2000 to be about 100, we find that the non-Gaussianities only make a minor difference with less than a few percent correction to uncertainties of most cosmological parameters determined from the data. For Planck, the resulting constraints on the sum of the neutrino masses is sigmaSigmamnu~0.2 eV and on the dark energy equation of state parameter we find that sigmaw~0.5. A post-Planck experiment can improve the neutrino mass measurement by a factor of 3 to 4.
|Additional Information:||© 2007 The American Physical Society. (Received 1 August 2006; revised 29 January 2007; published 5 April 2007) We thank Wayne Hu, Manoj Kaplinghat, and Kendrick Smith for useful discussions and communications. This work was supported in part by DoE at UC Irvine (A.C.), by the Moore Foundation at Caltech (C.L.), and a NSF graduate research grant (T.L.S.).|
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|Deposited On:||15 Aug 2007|
|Last Modified:||07 Dec 2016 21:49|
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