Non-Gaussian structure of the lensed CMB power spectra covariance matrix

Abstract

Gravitational lensing of the Cosmic Microwave Background (CMB) encodes cosmological information in the observed anisotropies of temperature and polarization. Accurate extraction of this additional information requires precise modeling of the covariance matrix of the power spectra of observed CMB fields. We introduce a new analytical model to describe the non-Gaussian structure of this covariance matrix and display the importance of second-order terms that were previously neglected. When compared with direct numerical simulations our model captures parameter errors to better than a few percent for cases where the non-Gaussianity causes an order unity degradation in errors. We also provide a detailed comparison between the information content of lensed CMB power spectra and ideal reconstruction of the lensing potential. We illustrate the impact of the non-Gaussian terms in the power spectrum covariance by providing Fisher errors on the sum of the masses of the neutrinos, the dark energy equation of state, and the curvature of the Universe.

Modified to match published version. References added

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Cited by in corpus (21)

• The Atacama Cosmology Telescope: A Measurement of the Cosmic Microwave Background Power Spectra at 98 and 150 GHz
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• CMB Polarization can constrain cosmology better than CMB temperature
• Full covariance of CMB and lensing reconstruction power spectra
• SPT-3G D1: CMB temperature and polarization power spectra and cosmology from 2019 and 2020 observations of the SPT-3G Main field
• The Benefits of CMB Delensing
• HYREC-2: a highly accurate sub-millisecond recombination code
• Distinguishing between Neutrinos and time-varying Dark Energy through Cosmic Time
• The Simons Observatory: Constraining inflationary gravitational waves with multi-tracer B-mode delensing
• DEMNUni: The imprint of massive neutrinos on the cross-correlation between cosmic voids and CMB lensing
• Calibrating Cluster Number Counts with CMB lensing
• Impact of internal-delensing biases on searches for primordial B-modes of CMB polarisation
• Multiple Lensing of the Cosmic Microwave Background anisotropies
• A numerical study of observational systematic errors in lensing analysis of CMB polarization
• CMB Lens Sample Covariance and Consistency Relations
• Improving Constraints on Models Addressing the Hubble Tension with CMB Delensing
• Improving Constraints on Inflation with CMB Delensing
• Lens covariance effects on likelihood analyses of CMB power spectra
• The Atacama Cosmology Telescope: Delensed Power Spectra and Parameters
• LiteBIRD science goals and forecasts: improved full-sky reconstruction of the gravitational lensing potential through the combination of Planck and LiteBIRD data