Lewis, Antony and Pratten, Geraint (2016) Effect of lensing non-Gaussianity on the CMB power spectra. Journal of Cosmology and Astroparticle Physics, 2016 (12). 003. ISSN 1475-7516
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Abstract
Observed CMB anisotropies are lensed, and the lensed power spectra can be calculated accurately assuming the lensing deflections are Gaussian. However, the lensing deflections are actually slightly non-Gaussian due to both non-linear large-scale structure growth and post-Born corrections. We calculate the leading correction to the lensed CMB power spectra from the non-Gaussianity, which is determined by the lensing bispectrum. The lowest-order result gives ∼0.3% corrections to the BB and EE polarization spectra on small-scales, however we show that the effect on EE is reduced by about a factor of two by higher-order Gaussian lensing smoothing, rendering the total effect safely negligible for the foreseeable future. We give a simple analytic model for the signal expected from skewness of the large-scale lensing field; the effect is similar to a net demagnification and hence a small change in acoustic scale (and therefore out of phase with the dominant lensing smoothing that predominantly affects the peaks and troughs of the power spectrum).
Item Type: | Article |
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Schools and Departments: | School of Mathematical and Physical Sciences > Physics and Astronomy |
Research Centres and Groups: | Astronomy Centre |
Subjects: | Q Science > QB Astronomy |
Depositing User: | Richard Chambers |
Date Deposited: | 13 Jan 2017 15:02 |
Last Modified: | 06 Dec 2017 02:00 |
URI: | http://srodev.sussex.ac.uk/id/eprint/66172 |
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📧 Request an updateProject Name | Sussex Project Number | Funder | Funder Ref |
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Precision cosmological parameters : CosmoPars | G1365 | EUROPEAN UNION | 616170 ERC-2013-CoG |
Astrophysics and Cosmology - Sussex Consolidated Grant | G1291 | STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCIL | ST/L000652/1 |