Rethinking CMB foregrounds: systematic extension of foreground parameterizations

Abstract

Future high-sensitivity measurements of the cosmic microwave background (CMB) anisotropies and energy spectrum will be limited by our understanding and modeling of foregrounds. Not only does more information need to be gathered and combined, but also novel approaches for the modeling of foregrounds, commensurate with the vast improvements in sensitivity, have to be explored. Here, we study the inevitable effects of spatial averaging on the spectral shapes of typical foreground components, introducing a moment approach, which naturally extends the list of foreground parameters that have to be determined through measurements or constrained by theoretical models. Foregrounds are thought of as a superposition of individual emitting volume elements along the line of sight and across the sky, which then are observed through an instrumental beam. The beam and line of sight averages are inevitable. Instead of assuming a specific model for the distributions of physical parameters, our method identifies natural new spectral shapes for each foreground component that can be used to extract parameter moments (e.g., mean, dispersion, cross-terms, etc.). The method is illustrated for the superposition of power-laws, free-free spectra, gray-body and modified blackbody spectra, but can be applied to more complicated fundamental spectral energy distributions. Here, we focus on intensity signals but the method can be extended to the case of polarized emission. The averaging process automatically produces scale-dependent spectral shapes and the moment method can be used to propagate the required information across scales in power spectrum estimates. The approach is not limited to applications to CMB foregrounds but could also be useful for the modeling of X-ray emission in clusters of galaxies.

19 pages, 8 figures, accepted by MNRAS, minor revisions

References in corpus (9)

• CMB-S4 Science Book, First Edition
• A refined model for spinning dust radiation
• Carbon monoxide line emission as a CMB foreground: tomography of the star-forming universe with different spectral resolutions
• Spatial variations in the spectral index of polarized synchrotron emission in the 9 yr WMAP sky maps
• A 3-D model of polarised dust emission in the Milky Way
• Spectral distortions from the dissipation of tensor perturbations
• C-Band All-Sky Survey: A First Look at the Galaxy
• ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: implications for spectral line intensity mapping at millimeter wavelengths and CMB spectral distortions
• Foreground Bias From Parametric Models of Far-IR Dust Emission

Cited by in corpus (73)

• The Simons Observatory: Science goals and forecasts
• Planck 2018 results. XI. Polarized dust foregrounds
• The Atacama Cosmology Telescope: Component-separated maps of CMB temperature and the thermal Sunyaev-Zel'dovich effect
• Prospects for Measuring Cosmic Microwave Background Spectral Distortions in the Presence of Foregrounds
• Exploring Cosmic Origins with CORE: B-mode Component Separation
• Peeling off foregrounds with the constrained moment ILC method to unveil primordial CMB $B$-modes
• Planck's view on the spectrum of the Sunyaev-Zeldovich effect
• CMB spectral distortions revisited: a new take on $\mu$ distortions and primordial non-Gaussianities from FIRAS data
• Spectral Index of the Diffuse Radio Background Between 50 and 100 MHz
• The C-Band All-Sky Survey (C-BASS): Design and capabilities
• Evidence for Line-of-Sight Frequency Decorrelation of Polarized Dust Emission in $Planck$ Data
• CMB Spectral Distortions: Status and Prospects
• Can we neglect relativistic temperature corrections in the Planck thermal SZ analysis?
• Mitigating Complex Dust Foregrounds in Future CMB Polarization Experiments
• A minimal power-spectrum-based moment expansion for CMB B-mode searches
• The Simons Observatory: gain, bandpass and polarization-angle calibration requirements for B-mode searches
• Characterizing bias on large scale CMB $B$-modes after galactic foregrounds cleaning
• Mapping the relativistic electron gas temperature across the sky
• Combining ILC and moment expansion techniques for extracting average-sky signals and CMB anisotropies
• Partially Constrained Internal Linear Combination: a method for low-noise CMB foreground mitigation
• The Simons Observatory: pipeline comparison and validation for large-scale B-modes
• $B$-mode forecast of CMB-Bh$\overline{a}$rat
• Foreground Separation and Constraints on Primordial Gravitational Waves with the PICO Space Mission
• Dust moments: towards a new modelling of the galactic dust emission for CMB B-modes analysis
• Extracting foreground-obscured $\mu$-distortion anisotropies to constrain primordial non-Gaussianity
• High precision modeling of polarized signals: Moment expansion method generalized to spin-2 fields
• Frequency dependence of the thermal dust $E/B$ ratio and $EB$ correlation: insights from the spin-moment expansion
• An improved Compton parameter map of thermal Sunyaev-Zeldovich effect from Planck PR4 data
• Tensor-to-scalar ratio forecasts for extended LiteBIRD frequency configurations
• Sensitivity forecasts for the cosmological recombination radiation in the presence of foregrounds
• Determining thermal dust emission from Planck HFI data using a sparse, parametric technique
• BICEP / Keck XVI: Characterizing Dust Polarization through Correlations with Neutral Hydrogen
• Dust polarization spectral dependence from Planck HFI data. Turning point on CMB polarization foregrounds modelling
• On the Detection of CMB B-modes from Ground at Low Frequency
• Full-sky, arcminute-scale, 3D models of Galactic microwave foreground dust emission based on filaments
• Improved Galactic Foreground Removal for B-Modes Detection with Clustering Methods
• Optimization of foreground moment deprojection for semi-blind CMB polarization reconstruction
• Refined modelling of the radio SZ signal: kinematic terms, relativistic temperature corrections and anisotropies in the radio background
• CCAT-prime: Science with an Ultra-widefield Submillimeter Observatory at Cerro Chajnantor
• Hierarchical Bayesian CMB Component Separation with the No-U-Turn Sampler
• Mitigating the impact of the CIB on galaxy cluster SZ detection with spectrally constrained matched filters
• The spectral index of polarized diffuse Galactic emission between 30 and 44 GHz
• Measuring the Hubble constant from the cooling of the CMB monopole
• Characterizing line-of-sight variability of polarized dust emission with future CMB experiments
• Impact of Dust on Spectral Distortion Measurements of the Cosmic Microwave Background
• New Horizons in Cosmology with Spectral Distortions of the Cosmic Microwave Background
• Impact of Galactic dust non-Gaussianity on searches for B-modes from inflation
• Generative Models of Multi-channel Data from a Single Example -- Application to Dust Emission
• Least response method to separate CMB spectral distortions from foregrounds
• The COSmic Monopole Observer (COSMO)
• How bad could it be? Modelling the 3D complexity of the polarised dust signal using moment expansion
• Separation of CMB $\mu$ spectral distortions from foregrounds with poorly defined spectral shapes
• Forecast of foreground cleaning strategies for AliCPT-1
• Cosmic star formation history with tomographic cosmic infrared background-galaxy cross-correlation
• Importance of intracluster scattering and relativistic corrections from tSZ effect with Cosmic Infrared Background
• The C-Band All-Sky Survey (C-BASS): Simulated parametric fitting in single pixels in total intensity and polarization
• Evaluation of the single-component thermal dust emission model in CMB experiments
• Mitigating Bias in CMB B-modes from Foreground Cleaning Using a Moment Expansion
• The Interstellar Dust Emission Spectrum, Going beyond the single temperature greybody
• Identifying frequency decorrelated dust residuals in B-mode maps by exploiting the spectral capability of bolometric interferometry
• The Simons Observatory: Assessing the Impact of Dust Complexity on the Recovery of Primordial $B$-modes
• New probe of inflationary gravitational waves: cross-correlations of lensed primary CMB B-modes with large-scale structure
• Galactic foreground constraints on primordial $B$-mode detection for ground-based experiments
• Self-supervised component separation for the extragalactic submillimeter sky
• Extended Delta-map: a map-based foreground removal method for CMB polarization observations
• Breaking degeneracies with the Sunyaev-Zeldovich full bispectrum
• Delensing for Precision Cosmology: Optimizing Future CMB B-mode Surveys to Constrain r
• SPECTER: An Instrument Concept for CMB Spectral Distortion Measurements with Enhanced Sensitivity
• Requirements on bandpass resolution and measurement precision for LiteBIRD
• SpyDust: an improved and extended implementation for modeling spinning dust radiation
• B-mode polarization forecasts for GreenPol
• A new approach of estimating the Galactic thermal dust and synchrotron polarized emission template in the microwave bands
• Mitigating Cosmic Microwave Background Shadow Degradation of Tensor-to-scalar Ratio Measurements through Map-based Studies