CMB lensing and primordial non-Gaussianity

Abstract

We study the effects of gravitational lensing on the estimation of non-Gaussianity from the bispectrum of the cosmic microwave background (CMB) temperature anisotropies. We find that the effect of lensing on the bispectrum may qualitatively be described as a smoothing of the acoustic features analogous to the temperature power spectrum. In contrast to previous results, for a Planck-like experiment which is cosmic-variance limited to L=2000, we find that lensing causes no significant degradation of our ability to constrain the non-Gaussianity amplitude fNL for both local and equilateral configurations, provided that the biases due to the cross correlation between the lensing potential and the integrated-Sachs-Wolfe (ISW) contribution to the CMB temperature are adequately understood. With numerical simulations, we also verify that low-order Taylor approximations to the lensed bispectrum and ISW-lensing biases are accurate.

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• General CMB and Primordial Bispectrum Estimation I: Mode Expansion, Map-Making and Measures of f_NL
• Planck 2013 results. XIX. The integrated Sachs-Wolfe effect
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• Non Gaussianity and Minkowski Functionals: forecasts for Planck
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• The CMB bispectrum in the squeezed limit
• Sachs-Wolfe at second order: the CMB bispectrum on large angular scales
• On the joint analysis of CMB temperature and lensing-reconstruction power spectra
• The intrinsic bispectrum of the Cosmic Microwave Background [PhD thesis]
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