Cosmic polarimetry in magnetoactive plasmas

Understand

Polarimetry of the Cosmic Microwave Background (CMB) represents one of the possible diagnostics aimed at testing large-scale magnetism at the epoch of the photon decoupling.

• The propagation of electromagnetic disturbances in a magnetized plasma leads naturally to a B-mode polarization whose angular power spectrum is hereby computed both analytically and numerically.
• Combined analyses of all the publicly available data on the B-mode polarization are presented, for the first time, in the light of the magnetized $\Lambda$CDM scenario.
• Novel constraints on pre-equality magnetism are also derived in view of the current and expected sensitivities to the B-mode polarization.