Foreground Mitigation for CMB Lensing with the Global Minimum Variance Quadratic Estimator

Abstract

Weak gravitational lensing of the cosmic microwave background (CMB) is a powerful probe of cosmology, providing insight into structure formation and the evolution of the universe. Current and upcoming CMB experiments such as SPT-3G and the Simons Observatory (SO) provide high-resolution, low-noise temperature and polarization maps that are ideal for lensing reconstruction. The global minimum variance (GMV) quadratic estimator for CMB lensing reduces reconstruction noise over the standard quadratic estimator (SQE). In this work, we extend the GMV framework to incorporate the tSZ-deproj and cross-ILC foreground mitigation techniques, which enhance robustness against contamination from astrophysical sources. For a simulation study using SPT-3G Ext-10k and SO Extended configurations at ${\ell }_{\max }^T=3500$, the lensing bias at $L<1000$ is reduced from $\sim 4\%$ with standard GMV and SQE to $2\%$ with tSZ-deproj, and to $<1\%$ with cross-ILC. These methods enable the construction of foreground-cleaned lensing maps suitable for cross-correlation analyses, with direct relevance for current and future surveys.

References in corpus (23)

• HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
• The Simons Observatory: Science goals and forecasts
• Weak Gravitational Lensing of the CMB
• CMB Lensing Reconstruction on the Full Sky
• Reconstruction of lensing from the cosmic microwave background polarization
• Combined analysis of the integrated Sachs-Wolfe effect and cosmological implications
• The Atacama Cosmology Telescope: A Measurement of the DR6 CMB Lensing Power Spectrum and its Implications for Structure Growth
• CMB and SZ effect separation with Constrained Internal Linear Combinations
• Bias-Hardened CMB Lensing
• Extragalactic Foreground Contamination in Temperature-based CMB Lens Reconstruction
• BICEP2 / Keck Array VIII: Measurement of gravitational lensing from large-scale B-mode polarization
• Mitigating Foreground Biases in CMB Lensing Reconstruction Using Cleaned Gradients
• Foreground-immune CMB lensing with shear-only reconstruction
• Cosmology From CMB Lensing and Delensed EE Power Spectra Using 2019-2020 SPT-3G Polarization Data
• Lower bias, lower noise CMB lensing with foreground-hardened estimators
• Quadratic estimators for CMB weak lensing
• A Measurement of Gravitational Lensing of the Cosmic Microwave Background Using SPT-3G 2018 Data
• The Atacama Cosmology Telescope: Two-season ACTPol Extragalactic Point Sources and their Polarization properties
• Fractional Polarisation of Extragalactic Sources in the 500-square-degree SPTpol Survey
• Measurement of the Cosmic Microwave Background Polarization Lensing Power Spectrum from Two Years of POLARBEAR Data
• Bias to CMB lensing from lensed foregrounds
• CMB lensing with shear-only reconstruction on the full sky
• A halo model of extragalactic contamination to CMB lensing, delensing, and cross-correlations