Full covariance of CMB and lensing reconstruction power spectra

Abstract

CMB and lensing reconstruction power spectra are powerful probes of cosmology. However they are correlated, since the CMB power spectra are lensed and the lensing reconstruction is constructed using CMB multipoles. We perform a full analysis of the auto- and cross-covariances, including polarization power spectra and minimum variance lensing estimators, and compare with simulations of idealized future CMB-S4 observations. Covariances sourced by fluctuations in the unlensed CMB and instrumental noise can largely be removed by using a realization-dependent subtraction of lensing reconstruction noise, leaving a relatively simple covariance model that is dominated by lensing-induced terms and well described by a small number of principal components. The correlations between the CMB and lensing power spectra will be detectable at the level of $\sim 5\sigma$ for a CMB-S4 mission, and neglecting those could underestimate some parameter error bars by several tens of percent. However we found that the inclusion of external priors or data sets to estimate parameter error bars can make the impact of the correlations almost negligible.

35 pages, 11 figures, 3 appendices. Minor changes to match the published version. Figure 1 has been updated with the correct display of error bars. Package available at https://github.com/JulienPeloton/lenscov

References in corpus (7)

• CMB temperature lensing power reconstruction
• Reconstructing Patchy Reionization from the Cosmic Microwave Background
• Cosmological Information from Lensed CMB Power Spectra
• Non-Gaussian structure of the lensed CMB power spectra covariance matrix
• Probing the neutrino mass hierarchy with CMB weak lensing
• Non-Gaussian Covariance of CMB B-modes of Polarization and Parameter Degradation
• CMBPol Mission Concept Study: Reionization Science with the Cosmic Microwave Background

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