Stokes parameters spectral distortions due to the Sunyaev-Zel'dovich effect and an independent estimation of the CMB low multipoles

TL;DR

This paper explores specific spectral distortions in the Stokes parameters caused by the Sunyaev-Zel'dovich effect on the CMB, proposing a method to independently estimate low multipole anisotropies and distinguish between different Sachs-Wolfe effects.

Contribution

It introduces a new analytical approach to identify distinctive spectral distortions in the CMB due to the SZ effect, enabling independent low-multipole anisotropy estimation.

Findings

Distinct spectral shape of the identified distortions.

Potential to separate SZ distortions from contaminants.

Feasibility of detection with future high-resolution space missions.

Abstract

We consider the Stokes parameters' frequency spectral distortions arising due to Compton scattering of the anisotropic cosmic microwave background (CMB) radiation, the Sunyaev-Zel' dovich effect (SZ), towards clusters of galaxies. We single out a very special type of such distortions and find simple analytical formulas for them. We show that this kind of distortion has a very distinctive spectral shape and can be separated from other kinds of contaminants. We demonstrate that this effect gives us an opportunity for an independent estimation of the low-multipole angular CMB anisotropies, such as the dipole, the quadrupole, and the octupole. We also show that, using distorted signals from nearby and distant clusters, one can distinguish between the Sachs-Wolfe and the integrated Sachs-Wolfe effects. The detection of such distortions can be feasible with high-angular resolution and high-sensitivity space missions, such as the upcoming Millimetron Space Observatory experiment.