Exploring cosmic origins with CORE: B-mode component separation

Abstract

We demonstrate that, for the baseline design of the CORE satellite mission, the polarized foregrounds can be controlled at the level required to allow the detection of the primordial cosmic microwave background (CMB) B-mode polarization with the desired accuracy at both reionization and recombination scales, for tensor-to-scalar ratio values of r ≾ 5 × 10−³ . We consider detailed sky simulations based on state-of-the-art CMB observations that consist of CMB polarization with τ = 0.055 and tensor-to-scalar values ranging from r = 10−² to 10−³ , Galactic synchrotron, and thermal dust polarization with variable spectral indices over the sky, polarized anomalous microwave emission, polarized infrared and radio sources, and gravitational lensing effects. Using both parametric and blind approaches, we perform full component separation and likelihood analysis of the simulations, allowing us to quantify both uncertainties and biases on the reconstructed primordial B-modes.