Separation of Gravitational-Wave and Cosmic-Shear Contributions to Cosmic Microwave Background Polarization
Inflationary gravitational waves (GW) contribute to the curl component in the polarization of the cosmic microwave background (CMB). Cosmic shear—gravitational lensing of the CMB—converts a fraction of the dominant gradient polarization to the curl component. Higher-order correlations can be used to map the cosmic shear and subtract this contribution to the curl. Arcminute resolution will be required to pursue GW amplitudes smaller than those accessible by the Planck surveyor mission. The blurring by lensing of small-scale CMB power leads with this reconstruction technique to a minimum detectable GW amplitude corresponding to an inflation energy near 10^15 GeV.
Additional Information© 2002 The American Physical Society Received 22 February 2002; revised 13 May 2002; published 18 June 2002 During the preparation of this paper, we learned of another very recently completed work by Knox and Song  that performs a very similar calculation and reaches similar conclusions. This work was supported in part by NSF AST-0096023, NASA NAG5-8506, and DOE DE-FG03-92-ER40701. Kesden acknowledges the support of the NSF, and A.C. acknowledges support from the Sherman Fairchild Foundation.
Published - KESprl02.pdf