Unbiased Primordial Gravitational Wave Inference from the CMB with SMICA

TL;DR

This paper demonstrates that using blind spectral matching ICA allows for unbiased estimation of primordial gravitational wave signals from CMB B-mode polarization data, even with complex foreground contamination, aiding current and future experiments.

Contribution

It introduces a novel application of spectral matching ICA to achieve unbiased primordial B-mode inference amidst complex foregrounds.

Findings

Unbiased primordial B-mode estimates are achievable with spectral matching ICA.

The method is effective even with highly complex foreground contamination.

Applicable to both current and future CMB experiments.

Abstract

The detection of primordial gravitational waves in Cosmic Microwave Background B-mode polarization observations requires accurate and robust subtraction of astrophysical contamination. We show, using a blind Spectral Matching Independent Component Analysis, that it is possible to infer unbiased estimates of the primordial B-mode signal from ground-based observations of a small patch of sky even for highly complex foreground contamination. This work, originally performed in the context of configuration studies for a future CMB-S4 observatory, is highly relevant for the analysis of observations by the current generation of CMB experiments.