CMB lensing reconstruction using cut sky polarization maps and pure-$B$ modes

Abstract

Detailed measurements of the CMB lensing signal are an important scientific goal of ongoing ground-based CMB polarization experiments, which are mapping the CMB at high resolution over small patches of the sky. In this work we simulate CMB polarization lensing reconstruction for the $EE$ and $EB$ quadratic estimators with current-generation noise levels and resolution, and show that without boundary effects the known and expected zeroth and first order $N^{(0)}$ and $N^{(1)}$ biases provide an adequate model for non-signal contributions to the lensing power spectrum estimators. Small sky areas present a number of additional challenges for polarization lensing reconstruction, including leakage of $E$ modes into $B$ modes. We show how simple windowed estimators using filtered pure-$B$ modes can greatly reduce the mask-induced mean-field lensing signal and reduce variance in the estimators. This provides a simple method (used with recent observations) that gives an alternative to more optimal but expensive inverse-variance filtering.

14 pages, 12 figures; Minor corrections and clarifications to match accepted version

References in corpus (2)

• CMB temperature lensing power reconstruction
• A general solution to the E-B mixing problem

Cited by in corpus (11)

• The Quest for B Modes from Inflationary Gravitational Waves
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• BICEP2 / Keck Array VIII: Measurement of gravitational lensing from large-scale B-mode polarization
• The Atacama Cosmology Telescope: Lensing of CMB Temperature and Polarization Derived from Cosmic Infrared Background Cross-Correlation
• Exploring cosmic origins with CORE: gravitational lensing of the CMB
• Lensing reconstruction from a patchwork of polarization maps
• Optimal filtering for CMB lensing reconstruction
• LiteBIRD Science Goals and Forecasts: A full-sky measurement of gravitational lensing of the CMB
• Impact of Galactic non-Gaussian foregrounds on CMB lensing measurements
• Constraining cosmic polarization rotation and implications for primordial B-modes
• A Demonstration of Spectral Level Reconstruction of Intrinsic $B$-mode Power