Optimal filtering for CMB lensing reconstruction

Abstract

Upcoming ground-based cosmic microwave background experiments will provide CMB maps with high sensitivity and resolution that can be used for high fidelity lensing reconstruction. However, the sky coverage will be incomplete and the noise highly anisotropic, so optimized estimators are required to extract the most information from the maps. We focus on quadratic-estimator based lensing reconstruction methods that are fast to implement, and compare new more-optimally filtered estimators with various estimators that have previously been used in the literature. Input CMB maps can be optimally inverse-signal-plus-noise filtered using conjugate gradient (or other) techniques to account for the noise anisotropy. However, lensing reconstructions from these filtered input maps have an anisotropic response to the lensing signal and are difficult to interpret directly. We describe a second-stage filtering of the lensing maps and analytic response model that can be used to construct lensing power spectrum estimates that account for the anisotropic response and noise inhomogeneity in an approximately optimal way while remaining fast to compute. We compare results for simulations of upcoming Simons Observatory and CMB Stage-4 experiments to show the robustness of the more optimal lensing reconstruction pipeline and quantify the improvement compared to less optimal estimators. We find a substantial improvement in reconstructed lensing power variance between optimal anisotropic and isotropic filtering of CMB maps, and up to 30% improvement in variance by using the additional filtering step on the reconstruction potential map. Our approximate analytic response model is unbiased to within a small percent-level additional Monte Carlo correction.

17 pages, 12 figures

References in corpus (32)

• Planck 2015 results. XIII. Cosmological parameters
• HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
• Efficient Computation of CMB anisotropies in closed FRW models
• The Simons Observatory: Science goals and forecasts
• Weak Gravitational Lensing of the CMB
• Mass Reconstruction with CMB Polarization
• CMB Lensing Reconstruction on the Full Sky
• Planck 2013 results. XVII. Gravitational lensing by large-scale structure
• Detection of Gravitational Lensing in the Cosmic Microwave Background
• Reconstruction of lensing from the cosmic microwave background polarization
• CMB-S4 Science Book, First Edition
• Planck 2015 results. XV. Gravitational lensing
• The shape of the CMB lensing bispectrum
• Lensing Reconstruction with CMB Temperature and Polarization
• Analyzing weak lensing of the cosmic microwave background using the likelihood function
• CMB temperature lensing power reconstruction
• A Measurement of the Cosmic Microwave Background Gravitational Lensing Potential from 100 Square Degrees of SPTpol Data
• The Atacama Cosmology Telescope: Two-Season ACTPol Lensing Power Spectrum
• A Measurement of the Cosmic Microwave Background $B$-Mode Polarization Power Spectrum at Sub-Degree Scales from 2 years of POLARBEAR Data
• Pseudo-$C_{\ell }$ estimators which do not mix E and B modes
• Weak lensing of the CMB
• BICEP2 / Keck Array VIII: Measurement of gravitational lensing from large-scale B-mode polarization
• Maximum a posteriori CMB lensing reconstruction
• On the joint analysis of CMB temperature and lensing-reconstruction power spectra
• CMB lensing reconstruction biases in cross-correlation with large-scale structure probes
• Full-sky CMB lensing reconstruction in presence of sky-cuts
• Lensing reconstruction from a patchwork of polarization maps
• A hybrid approach to CMB lensing reconstruction on all-sky intensity maps
• Designs for next generation CMB survey strategies from Chile
• Fast Wiener filtering of CMB maps with Neural Networks
• CMB lensing reconstruction using cut sky polarization maps and pure-$B$ modes
• CMB-S4 Decadal Survey APC White Paper

Cited by in corpus (15)

• The Atacama Cosmology Telescope: DR6 Gravitational Lensing Map and Cosmological Parameters
• CMB lensing from Planck PR4 maps
• Recombination-independent determination of the sound horizon and the Hubble constant from BAO
• Bayesian delensing delight: sampling-based inference of the primordial CMB and gravitational lensing
• CMB-S4: Iterative Internal Delensing and $r$ Constraints
• CMB lensing power spectrum estimation without instrument noise bias
• Planck ISW-lensing likelihood and the CMB temperature
• CMB lensing reconstruction biases from masking extragalactic sources
• Instrumental systematics biases in CMB lensing reconstruction: a simulation-based assessment
• Real-world CMB lensing quadratic estimator power spectrum response
• LiteBIRD Science Goals and Forecasts: A full-sky measurement of gravitational lensing of the CMB
• Constraints on ${\tau }_{\mathrm{NL}}$ from Planck temperature and polarization
• CMB lensing power spectrum without noise bias
• LiteBIRD science goals and forecasts: improved full-sky reconstruction of the gravitational lensing potential through the combination of Planck and LiteBIRD data
• A CMB lensing analysis of the extended mass distribution of clusters