Mitigating Foreground Bias to the CMB Lensing Power Spectrum for a CMB-HD Survey

Abstract

A promising way to measure the distribution of matter on small scales (k ~ 10 hMpc^-1) is to use gravitational lensing of the Cosmic Microwave Background (CMB). CMB-HD, a proposed high-resolution, low-noise millimeter survey over half the sky, can measure the CMB lensing auto spectrum on such small scales enabling measurements that can distinguish between a cold dark matter (CDM) model and alternative models designed to solve problems with CDM on small scales. However, extragalactic foregrounds can bias the CMB lensing auto spectrum if left untreated. We present a foreground mitigation strategy that provides a path to reduce the bias from two of the most dominant foregrounds, the thermal Sunyaev-Zel'dovich effect (tSZ) and the Cosmic Infrared Background (CIB). Given the level of realism included in our analysis, we find that the tSZ alone and the CIB alone bias the lensing auto spectrum by 0.6 sigma and 1.1 sigma respectively, in the lensing multipole range of L in [5000,20000] for a CMB-HD survey; combined these foregrounds yield a bias of only 1.3 sigma. Including these foregrounds, we also find that a CMB-HD survey can distinguish between a CDM model and a 10^-22 eV FDM model at the 5 sigma level. These results provide an important step in demonstrating that foreground contamination can be sufficiently reduced to enable a robust measurement of the small-scale matter power spectrum with CMB-HD.

14 pages, 6 figures; power spectra and lensing covariance matrix from this analysis are public at https://github.com/dwhan89/hdlensing

References in corpus (16)

• Ultralight scalars as cosmological dark matter
• Too big to fail? The puzzling darkness of massive Milky Way subhaloes
• Dark Energy Survey Year 3 Results: Cosmological Constraints from Galaxy Clustering and Weak Lensing
• Cosmic Structure as the Quantum Interference of a Coherent Dark Wave
• Dark matter and cosmic structure
• A measurement of secondary cosmic microwave background anisotropies from the 2500-square-degree SPT-SZ survey
• The Atacama Cosmology Telescope: Combined kinematic and thermal Sunyaev-Zel'dovich measurements from BOSS CMASS and LOWZ halos
• Evidence of Lensing of the Cosmic Microwave Background by Dark Matter Halos
• Emulation of baryonic effects on the matter power spectrum and constraints from galaxy cluster data
• Constraining Cluster Virialization Mechanism and Cosmology using Thermal-SZ-selected clusters from Future CMB Surveys
• Systematic errors in the measurement of neutrino masses due to baryonic feedback processes: Prospects for stage IV lensing surveys
• MillimeterDL: Deep Learning Simulations of the Microwave Sky
• Re-Examining Astrophysical Constraints on the Dark Matter Model
• Reconstructing Patchy Reionization with Deep Learning
• DeepSZ: Identification of Sunyaev-Zel'dovich Galaxy Clusters using Deep Learning
• Reconstructing Cosmic Polarization Rotation with ResUNet-CMB

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• LiteBIRD Science Goals and Forecasts: A full-sky measurement of gravitational lensing of the CMB
• Subtracting the kinetic Sunyaev-Zeldovich effect from the cosmic microwave background with surveys of large-scale structure
• Unveiling Neutrino Halos with CMB Lensing
• kSZ Pairwise Velocity Reconstruction with Machine Learning
• Small Correlated Against Large Estimator (SCALE) for Cosmic Microwave Background Lensing
• Revisiting secondary CMB distortions due to kinetic Sunyaev-Zel'dovich effect from quasar bubbles before reionization