Astrophysical foregrounds and primordial tensor-to-scalar ratio constraints from CMB B-mode polarization observations

Abstract

We study the effects of astrophysical foregrounds on the ability of CMB B-mode polarization experiments to constrain the primordial tensor-to-scalar ratio, r. To clean the foreground contributions we use parametric, maximum likelihood component separation technique, and consider experimental setups optimized to render a minimal level of the foreground residuals in the recovered CMB map. We consider nearly full-sky observations, include two diffuse foreground components, dust and synchrotron, and study cases with and without calibration errors, spatial variability of the foreground properties, and partial or complete B-mode lensing signal removal. In all these cases we find that in the limit of very low noise level and in the absence of the intrumental or modeling systematic effects, the foreground residuals do not lead to a limit on the lowest detectable value of r. But the need to control the foreground residuals will play a major role in determining the minimal noise levels necessary to permit a robust detection of r < 0.1 and therefore in optimizing and forecasting the performance of the future missions. For current and proposed experiments noise levels, the foreground residuals are found non-negligible and potentially can affect our ability to set constraints on r. We also show how the constraints can be significantly improved on by restricting the post component separation processing to a smaller sky area. This procedure applied to a case of a COrE-like satellite mission is shown to result potentially in over an order of magnitude improvement in the detectable value of r. With sufficient knowledge of the experimental bandpasses as well as foreground component scaling laws, our conclusions are found to be independent on the assumed overall normalization of the foregrounds and only quantitatively depend on specific parametrizations assumed for the foreground components.

arXiv comment5 pages, 2 figures

References in corpus (20)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Likelihoods and Parameters from the WMAP data
• Signature of Gravity Waves in Polarization of the Microwave Background
• A Probe of Primordial Gravity Waves and Vorticity
• The Primordial Inflation Explorer (PIXIE): A Nulling Polarimeter for Cosmic Microwave Background Observations
• Mass Reconstruction with CMB Polarization
• A CMB Polarization Primer
• A limit on the detectability of the energy scale of inflation
• On Foreground Removal from the Wilkinson Microwave Anisotropy Probe Data by an Internal Linear Combination Method: Limitations and Implications
• Gravitational lensing as a contaminant of the gravity wave signal in CMB
• Separation of Gravitational-Wave and Cosmic-Shear Contributions to Cosmic Microwave Background Polarization
• CMB component separation by parameter estimation
• Maximum Likelihood algorithm for parametric component separation in CMB experiments
• Detectability of Inflationary Gravitational Waves with Microwave Background Polarization
• Limits on the detectability of the CMB B-mode polarization imposed by foregrounds
• Measuring the tensor to scalar ratio from CMB B-modes in presence of foregrounds
• All-sky component separation in the presence of anisotropic noise and dust temperature variations
• Maximum likelihood, parametric component separation and CMB B-mode detection in suborbital experiments
• Search for Gravitational Waves in the CMB After WMAP3: Foreground Confusion and The Optimal Frequency Coverage for Foreground Minimization
• Framework for performance forecasting and optimization of CMB B-mode observations in presence of astrophysical foregrounds
• Estimating the tensor-to-scalar ratio and the effect of residual foreground contamination

Cited by in corpus (17)

• Robust forecasts on fundamental physics from the foreground-obscured, gravitationally-lensed CMB polarization
• Sensitivity and foreground modelling for large-scale CMB B-mode polarization satellite missions
• Exploring Cosmic Origins with CORE: B-mode Component Separation
• Forecasting performance of CMB experiments in the presence of complex foreground contaminations
• A 3-D model of polarised dust emission in the Milky Way
• Characterizing bias on large scale CMB $B$-modes after galactic foregrounds cleaning
• C-Band All-Sky Survey: A First Look at the Galaxy
• The Simons Observatory: pipeline comparison and validation for large-scale B-modes
• High precision simulations of weak lensing effect on Cosmic Microwave Background polarization
• The Effects of Bandpass Variations on Foreground Removal Forecasts for Future CMB Experiments
• The C-Band All-Sky Survey (C-BASS): Constraining diffuse Galactic radio emission in the North Celestial Pole region
• A new model of the microwave polarized sky for CMB experiments
• Impact of modelling foreground uncertainties on future CMB polarization satellite experiments
• Foreground removal requirements for measuring large-scale CMB B-modes in light of BICEP2
• Detecting the tensor-to-scalar ratio with the pure pseudospectrum reconstruction of $B$-mode
• Galactic foreground constraints on primordial $B$-mode detection for ground-based experiments
• Cosmic Microwave Background Science at Commercial Airline Altitudes