Mitigating Bias in CMB B-modes from Foreground Cleaning Using a Moment Expansion

Abstract

One of the primary challenges facing upcoming CMB polarization experiments aiming to measure the inflationary B-mode signal is the removal of polarized foregrounds. The thermal dust foreground is often modeled as a single modified blackbody, however overly simplistic foreground models can bias measurements of the tensor-to-scalar ratio r. As CMB polarization experiments become increasingly sensitive, thermal dust emission models must account for greater complexity in the dust foreground while making minimal assumptions about the underlying distribution of dust properties within a beam. We use Planck dust temperature data to estimate the typical variation in dust properties along the line of sight and examine the impact of these variations on the bias in r if a single modified blackbody model is assumed. We then assess the ability of the moment method to capture the effects of spatial averaging and to reduce bias in the tensor-to-scalar ratio for different possible toy models of dust emission. We find that the expected bias due to temperature variations along the line of sight is significant compared to the target sensitivities of future CMB experiments, and that the use of the moment method could reduce bias as well as shed light into the distribution of dust physical parameters.

arXiv comment12 pages, 10 figures. Accepted for publication in ApJ

References in corpus (26)

• emcee: The MCMC Hammer
• HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
• BICEP / Keck XIII: Improved Constraints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season
• The Primordial Inflation Explorer (PIXIE): A Nulling Polarimeter for Cosmic Microwave Background Observations
• Extrapolation of Galactic Dust Emission at 100 Microns to CMBR Frequencies Using FIRAS
• Mission design of LiteBIRD
• PRISM (Polarized Radiation Imaging and Spectroscopy Mission): An Extended White Paper
• Power spectrum estimation from high-resolution maps by Gibbs sampling
• Planck 2018 results. XI. Polarized dust foregrounds
• Far-infrared to millimeter astrophysical dust emission I: A model based on physical properties of amorphous solids
• Rethinking CMB foregrounds: systematic extension of foreground parameterizations
• High angular resolution Sunyaev-Zel'dovich observations of MACS J1423.8+2404 with NIKA: Multiwavelength analysis
• Dust models compatible with Planck intensity and polarization data in translucent lines of sight
• The Dielectric Function of "Astrodust" and Predictions for Polarization in the 3.4$\mu$m and 10$\mu$m Features
• Sensitivity and foreground modelling for large-scale CMB B-mode polarization satellite missions
• Peeling off foregrounds with the constrained moment ILC method to unveil primordial CMB $B$-modes
• Far-Infrared to Millimeter Astrophysical Dust Emission. II: Comparison of the Two-Level Systems (TLS) model with Astronomical Data
• Forecasting performance of CMB experiments in the presence of complex foreground contaminations
• Mitigating Complex Dust Foregrounds in Future CMB Polarization Experiments
• First Observation of the Submillimeter Polarization Spectrum in a Translucent Molecular Cloud
• Combining ILC and moment expansion techniques for extracting average-sky signals and CMB anisotropies
• Impact on the tensor-to-scalar ratio of incorrect Galactic foreground modelling
• Estimating the tensor-to-scalar ratio and the effect of residual foreground contamination
• Foreground Bias From Parametric Models of Far-IR Dust Emission
• From B Modes to Quantum Gravity and Unification of Forces
• Limits on Polarized Dust Spectral Index Variations for CMB Foreground Analysis

Cited by in corpus (4)

• Frequency dependence of the thermal dust $E/B$ ratio and $EB$ correlation: insights from the spin-moment expansion
• Impact of Galactic dust non-Gaussianity on searches for B-modes from inflation
• How bad could it be? Modelling the 3D complexity of the polarised dust signal using moment expansion
• The Simons Observatory: Design, Optimization, and Performance of Low Frequency Detectors