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Title: Full covariance of CMB and lensing reconstruction power spectra

Authors:
; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1343469
Grant/Contract Number:
AC02-05CH11231
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review D
Additional Journal Information:
Journal Volume: 95; Journal Issue: 4; Related Information: CHORUS Timestamp: 2017-02-10 22:11:28; Journal ID: ISSN 2470-0010
Publisher:
American Physical Society
Country of Publication:
United States
Language:
English

Citation Formats

Peloton, Julien, Schmittfull, Marcel, Lewis, Antony, Carron, Julien, and Zahn, Oliver. Full covariance of CMB and lensing reconstruction power spectra. United States: N. p., 2017. Web. doi:10.1103/PhysRevD.95.043508.
Peloton, Julien, Schmittfull, Marcel, Lewis, Antony, Carron, Julien, & Zahn, Oliver. Full covariance of CMB and lensing reconstruction power spectra. United States. doi:10.1103/PhysRevD.95.043508.
Peloton, Julien, Schmittfull, Marcel, Lewis, Antony, Carron, Julien, and Zahn, Oliver. Fri . "Full covariance of CMB and lensing reconstruction power spectra". United States. doi:10.1103/PhysRevD.95.043508.
@article{osti_1343469,
title = {Full covariance of CMB and lensing reconstruction power spectra},
author = {Peloton, Julien and Schmittfull, Marcel and Lewis, Antony and Carron, Julien and Zahn, Oliver},
abstractNote = {},
doi = {10.1103/PhysRevD.95.043508},
journal = {Physical Review D},
number = 4,
volume = 95,
place = {United States},
year = {Fri Feb 10 00:00:00 EST 2017},
month = {Fri Feb 10 00:00:00 EST 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevD.95.043508

Citation Metrics:
Cited by: 7works
Citation information provided by
Web of Science

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  • We present a method of lensing reconstruction on the full sky, by extending the optimal quadratic estimator proposed by Okamoto and Hu (2003) to the case including the curl mode of deflection angle. The curl mode is induced by the vector and tensor metric perturbations, and the reconstruction of the curl mode would be a powerful tool to not only check systematics in the estimated gradient mode but also probe any vector and tensor sources. We find that the gradient and curl modes can be reconstructed separately, thanks to the distinctive feature in the parity symmetry between the gradient andmore » curl modes. We compare our estimator with the flat-sky estimator proposed by Cooray et al (2005). Based on the new formalism, the expected signal-to-noise ratio of the curl mode produced by the primordial gravitational-waves and a specific model of cosmic strings are estimated, and prospects for future observations are discussed.« less
  • We study the reconstruction of the lensing potential power spectrum from CMB temperature data, with an eye to the Planck experiment. We work with the optimal quadratic estimator of Okamoto and Hu, which we characterize thoroughly in an application to the reconstruction of the lensing power spectrum. We find that at multipoles L<250, our current understanding of this estimator is biased at the 15% level by beyond-gradient terms in the Taylor expansion of lensing effects. We present the full lensed trispectrum to fourth order in the lensing potential to explain this effect. We show that the low-L bias, as wellmore » as a previously known bias at high L, is relevant to the determination of cosmology and must be corrected for in order to avoid significant parameter errors. We also investigate the covariance of the reconstructed power, finding broad correlations of {approx_equal}0.1%. Finally, we discuss several small improvements which may be made to the optimal estimator to mitigate these problems.« less
  • Cited by 25
  • 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. Assuming no primordial non-Gaussianity, 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,more » 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).« less