Impact of Galactic non-Gaussian foregrounds on CMB lensing measurements

Abstract

Weak gravitational lensing of the CMB has been established as a robust and powerful observable for precision cosmology. However, the impact of Galactic foregrounds, which has been studied less extensively than many other potential systematics, could in principle pose a problem for CMB lensing measurements. These foregrounds are inherently non-Gaussian and hence might mimic the characteristic signal that lensing estimators are designed to measure. We present an analysis that quantifies the level of contamination from Galactic dust in lensing measurements, focusing particularly on measurements with the Atacama Cosmology Telescope and the Simons Observatory. We employ a whole suite of foreground models and study the contamination of lensing measurements with both individual frequency channels and multifrequency combinations. We test the sensitivity of different estimators to the level of foreground non-Gaussianity, and the dependence on sky fraction and multipole range used. We find that Galactic foregrounds do not present a problem for the Atacama Cosmology Telescope experiment (the bias in the inferred CMB lensing power spectrum amplitude remains below $0.3\sigma$). For Simons Observatory, not all foreground models remain below this threshold. Although our results are conservative upper limits, they suggest that further work on characterizing dust biases and determining the impact of mitigation methods is well motivated, especially for the largest sky fractions.

26 pages, 18 figures, PRD accepted version

References in corpus (28)

• The NumPy array: a structure for efficient numerical computation
• The Atacama Cosmology Telescope: DR6 Gravitational Lensing Map and Cosmological Parameters
• SPT-3G: A Next-Generation Cosmic Microwave Background Polarization Experiment on the South Pole Telescope
• The Atacama Cosmology Telescope: A Measurement of the DR6 CMB Lensing Power Spectrum and its Implications for Structure Growth
• Planck intermediate results. XXII. Frequency dependence of thermal emission from Galactic dust in intensity and polarization
• Optical Design of the Atacama Cosmology Telescope and the Millimeter Bolometric Array Camera
• CMB temperature lensing power reconstruction
• LiteBIRD: JAXA's new strategic L-class mission for all-sky surveys of cosmic microwave background polarization
• Mapping the Magnetic Interstellar Medium in Three Dimensions Over the Full Sky with Neutral Hydrogen
• Cosmology From CMB Lensing and Delensed EE Power Spectra Using 2019-2020 SPT-3G Polarization Data
• The Origin of Parity Violation in Polarized Dust Emission and Implications for Cosmic Birefringence
• A Measurement of Gravitational Lensing of the Cosmic Microwave Background Using SPT-3G 2018 Data
• A 3-D model of polarised dust emission in the Milky Way
• Foreground-immune CMB lensing reconstruction with polarization
• Detecting the polarization induced by scattering of the microwave background quadrupole in galaxy clusters
• Lensing power spectrum of the Cosmic Microwave Background with deep polarization experiments
• Non-Gaussian modelling and statistical denoising of Planck dust polarization full-sky maps using scattering transforms
• Determining thermal dust emission from Planck HFI data using a sparse, parametric technique
• The Atacama Cosmology Telescope: Map-Based Noise Simulations for DR6
• Statistical diagnostics to identify Galactic foregrounds in B-mode maps
• Full-sky, arcminute-scale, 3D models of Galactic microwave foreground dust emission based on filaments
• Robust and efficient CMB lensing power spectrum from polarization surveys
• CMB lensing reconstruction in the presence of diffuse polarized foregrounds
• Filamentary Dust Polarization and the Morphology of Neutral Hydrogen Structures
• Generative models of astrophysical fields with scattering transforms on the sphere
• Modeling parity-violating spectra in Galactic dust polarization with filaments and its applications to cosmic birefringence searches
• New probe of inflationary gravitational waves: cross-correlations of lensed primary CMB B-modes with large-scale structure
• ForSE+: Simulating non-Gaussian CMB foregrounds at 3 arcminutes in a stochastic way based on a generative adversarial network

Cited by in corpus (1)

• The Atacama Cosmology Telescope: A demonstration of CMB lensing measurement from daytime data