# Polarization of the Cosmic Infrared Background Fluctuations

## TL;DR

This paper predicts the polarization characteristics of the cosmic infrared background (CIB), showing that its B-mode polarization is negligible for current inflationary B-mode searches but could be detectable in future submillimetre observations.

## Contribution

It provides a theoretical prediction of CIB polarization correlations using an intrinsic alignment model, highlighting the negligible B-mode polarization for current experiments and potential detectability in future missions.

## Key findings

- CIB polarization is slightly aligned with galaxy tidal fields.
- Electric and B-mode polarizations are generated equally with very low power.
- CIB B-mode is negligible for current CMB B-mode searches but detectable in future submillimetre observations.

## Abstract

The cosmic infrared background (CIB) is slightly polarized. Polarization directions of individual galaxies could be aligned with tidal fields around galaxies, resulting in nonzero CIB polarization. We use a linear intrinsic alignment model to theoretically predict angular correlations of the CIB polarization fluctuations and find that electriclike and curl-like ($B$-mode) polarization modes are equally generated with power four orders of magnitude less than its intensity. The CIB $B$-mode signal is negligible and not a concerning foreground for the inflationary $B$-mode searches at nominal frequencies for cosmic microwave background measurements, but could be detected at submillimetre wavelengths by future space missions.