CMB Polarization B-mode Delensing with SPTpol and Herschel

Abstract

We present a demonstration of delensing the observed cosmic microwave background (CMB) B-mode polarization anisotropy. This process of reducing the gravitational-lensing generated B-mode component will become increasingly important for improving searches for the B modes produced by primordial gravitational waves. In this work, we delens B-mode maps constructed from multi-frequency SPTpol observations of a 90 deg${}^2$ patch of sky by subtracting a B-mode template constructed from two inputs: SPTpol E-mode maps and a lensing potential map estimated from the $\text{Herschel}$ $500\mu m$ map of the CIB. We find that our delensing procedure reduces the measured B-mode power spectrum by 28% in the multipole range $300<\ell <2300$; this is shown to be consistent with expectations from theory and simulations and to be robust against systematics. The null hypothesis of no delensing is rejected at $6.9\sigma$. Furthermore, we build and use a suite of realistic simulations to study the general properties of the delensing process and find that the delensing efficiency achieved in this work is limited primarily by the noise in the lensing potential map. We demonstrate the importance of including realistic experimental non-idealities in the delensing forecasts used to inform instrument and survey-strategy planning of upcoming lower-noise experiments, such as CMB-S4.

17 pages, 10 figures. Comments are welcomed

References in corpus (12)

• The NumPy array: a structure for efficient numerical computation
• CMB-S4 Science Book, First Edition
• SPT-3G: A Next-Generation Cosmic Microwave Background Polarization Experiment on the South Pole Telescope
• A measurement of secondary cosmic microwave background anisotropies from the 2500-square-degree SPT-SZ survey
• Measurements of Sub-degree B-mode Polarization in the Cosmic Microwave Background from 100 Square Degrees of SPTpol Data
• A general solution to the E-B mixing problem
• Unbiased Estimation of an Angular Power Spectrum
• Internal delensing of Planck CMB temperature and polarization
• Demonstration of cosmic microwave background delensing using the cosmic infrared background
• Measurements of E-Mode Polarization and Temperature-E-Mode Correlation in the Cosmic Microwave Background from 100 Square Degrees of SPTpol Data
• An upper limit to polarized submillimetre emission in Arp 220
• CMB internal delensing with general optimal estimator for higher-order correlations

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• Dark Energy Survey Year 1 Results: Curved-Sky Weak Lensing Mass Map
• Constraints on Cosmological Parameters from the 500 deg${}^2$ SPTpol Lensing Power Spectrum
• DeepCMB: Lensing Reconstruction of the Cosmic Microwave Background with Deep Neural Networks
• Searching for Anisotropic Cosmic Birefringence with Polarization Data from SPTpol
• Exploring cosmic origins with CORE: gravitational lensing of the CMB
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• Year two instrument status of the SPT-3G cosmic microwave background receiver
• A Demonstration of Improved Constraints on Primordial Gravitational Waves with Delensing
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• The Simons Observatory: Constraining inflationary gravitational waves with multi-tracer B-mode delensing
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• Optimal constraints on primordial gravitational waves from the lensed CMB
• LiteBIRD Science Goals and Forecasts: Improving Sensitivity to Inflationary Gravitational Waves with Multitracer Delensing
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• Performance of Al-Mn Transition-Edge Sensor Bolometers in SPT-3G
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• Joint Bayesian estimation of tensor and lensing B-modes in the power spectrum of CMB polarization data
• Forecast of foreground cleaning strategies for AliCPT-1
• Lensing Bias to CMB Polarization Measurements of Compensated Isocurvature Perturbations
• Characterization of Extragalactic Point-Sources on E- and B-mode Maps of the CMB Polarization
• Stage IV CMB forecasts for warm inflation
• Enhancing Primordial B-mode Detection: Comprehensive Delensing Pipelines for Improved Sensitivity to $r$
• Delensing for Precision Cosmology: Optimizing Future CMB B-mode Surveys to Constrain r
• Approximate Likelihood Approaches for Detecting the Influence of Primordial Gravitational Waves in Cosmic Microwave Background Polarization
• LiteBIRD science goals and forecasts: improved full-sky reconstruction of the gravitational lensing potential through the combination of Planck and LiteBIRD data
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