Spectral distortions in the cosmic microwave background polarization

Abstract

We compute the spectral distortions of the Cosmic Microwave Background (CMB) polarization induced by non-linear effects in the Compton interactions between CMB photons and cold intergalactic electrons. This signal is of the $y$-type and is dominated by contributions arising from the reionized era. We stress that it is not shadowed by the thermal SZ effect which has no equivalent for polarization. We decompose its angular dependence into $E$- and $B$-modes, and we calculate the corresponding power spectra, both exactly and using a suitable Limber approximation that allows a simpler numerical evaluation. We find that $B$-modes are of the same order of magnitude as $E$-modes. Both spectra are relatively flat, peaking around $\ell =280$, and their overall amplitude is directly related to the optical depth to reionization. Moreover, we find this effect to be one order of magnitude larger than the non-linear kinetic Sunyaev-Zel'dovich effect in galaxy clusters. Finally, we discuss how to improve the detectability of our signal by cross-correlating it with other quantities sourced by the flow of intergalactic electrons.

24 pages, 6 figures. Discussion about the effects of an extended period of reionization added and further comparison with previous works. Matches version published in JCAP

References in corpus (4)

• Extended Limber Approximation
• Relativistic cosmology and large-scale structure
• The intrinsic bispectrum of the Cosmic Microwave Background [PhD thesis]
• Parameterization of temperature and spectral distortions in future CMB experiments

Cited by in corpus (12)

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• The intrinsic B-mode polarisation of the Cosmic Microwave Background
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• Parameterization of temperature and spectral distortions in future CMB experiments
• Non-linear relativistic contributions to the cosmological weak-lensing convergence
• Radiative transport of relativistic species in cosmology
• CMB spectral distortions as solutions to the Boltzmann equations
• Unified approach to secondary effects on the CMB B-mode polarization
• E and B modes of the CMB y-type distortions: polarised kinetic Sunyaev-Zeldovich effect from the reionisation and post-reionisation eras
• Estimators for the cross-pairwise kSZ effect: forecasts for the dark energy and modified gravity parameters with Simons Observatory and CMB-S4
• The pairwise and cross-pairwise y-type polarised kinetic Sunyaev Zeldovich effect from transverse velocity of galaxy clusters
• Cosmic microwave background spectral distortions from Rayleigh scattering at second order