Polarization of the Cosmic Infrared Background Fluctuations

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.