Reconstruction of Gravitational Lensing Using WMAP 7-Year Data
Authors: Chang Feng, Brian Keating, Hans P. Paar, Oliver Zahn
http://arxiv.org/abs/1111.2371v1
Abstract: Gravitational lensing by large scale structure introduces non-Gaussianity into the Cosmic Microwave Background and imprints a new observable, which can be used as a cosmological probe. We apply a four-point estimator to the Wilkinson Microwave Anisotropy Probe (WMAP) 7-year coadded temperature maps alone to reconstruct the gravitational lensing signal. The Gaussian bias is simulated and subtracted, and the higher order bias is investigated. We measure a gravitational lensing signal with a statistical amplitude of $\mathcal {C}$ = $1.27\pm 0.98$ using all the correlations of the W- and V-band Differencing Assemblies (DAs). We therefore conclude that WMAP 7-year data alone, can not detect lensing.
Comments: The authors have applied an optimal quadratic estimator (W. Hu, Phys. Rev. D64,083005 (2001) and W. Hu, Astrophys. J. Lett. 557, 79 (2001)) to WMAP-7 temperature maps alone for the first time. They find evidence of lensing only at 1.30sigma.
