CMB internal delensing with general optimal estimator for higher-order correlations

Abstract

We present a new method for delensing $B$ modes of the cosmic microwave background (CMB) using a lensing potential reconstructed from the same realization of the CMB polarization (CMB internal delensing). The $B$-mode delensing is required to improve sensitivity to primary $B$ modes generated by, e.g., the inflationary gravitational waves, axion-like particles, modified gravity, primordial magnetic fields, and topological defects such as cosmic strings. However, the CMB internal delensing suffers from substantial biases due to correlations between observed CMB maps to be delensed and that used for reconstructing a lensing potential. We construct a realization-dependent (RD) estimator for correcting these biases by deriving a general optimal estimator for higher-order correlations. The RD estimator is less sensitive to simulation uncertainties. Compared to the previous methods, we find that the RD estimator corrects the biases without substantial degradation of the delensing efficiency.

18 pages, 8 figures, accepted for publication in PRD

References in corpus (5)

• CMB temperature lensing power reconstruction
• Demonstration of cosmic microwave background delensing using the cosmic infrared background
• B polarization of cosmic microwave background as a tracer of strings
• CMB Lensing Beyond the Power Spectrum: Cosmological Constraints from the One-Point PDF and Peak Counts
• Lensing reconstruction from a patchwork of polarization maps

Cited by in corpus (22)

• Planck 2018 results. VIII. Gravitational lensing
• CMB Polarization B-mode Delensing with SPTpol and Herschel
• The Benefits of CMB Delensing
• Internal delensing of Cosmic Microwave Background polarization B-modes with the POLARBEAR experiment
• The Simons Observatory: Constraining inflationary gravitational waves with multi-tracer B-mode delensing
• CMB-S4: Iterative Internal Delensing and $r$ Constraints
• Impact of Polarized Galactic Foreground Emission on CMB Lensing Reconstruction and Delensing of B-Modes
• Future cosmic microwave background delensing with galaxy surveys
• Impact of internal-delensing biases on searches for primordial B-modes of CMB polarisation
• Limitations of CMB B-mode template delensing
• Dark neutrino interactions make gravitational waves blue
• Comparison of delensing methodologies and assessment of the delensing capabilities of future experiments
• LiteBIRD Science Goals and Forecasts: Improving Sensitivity to Inflationary Gravitational Waves with Multitracer Delensing
• Optimal constraints on primordial gravitational waves from the lensed CMB
• The impact of extragalactic foregrounds on internal delensing of CMB B-mode polarization
• CMB Mode Coupling with Isotropic Polarization Rotation
• A numerical study of observational systematic errors in lensing analysis of CMB polarization
• Impact of nonlinear growth of the large-scale structure on CMB B-mode delensing
• The reconstructed CMB lensing bispectrum
• The Atacama Cosmology Telescope: Delensed Power Spectra and Parameters
• Joint Bayesian estimation of tensor and lensing B-modes in the power spectrum of CMB polarization data
• LiteBIRD science goals and forecasts: improved full-sky reconstruction of the gravitational lensing potential through the combination of Planck and LiteBIRD data