Detectability of Galactic Faraday Rotation in Multi-wavelength CMB
  Observations: A Cross-Correlation Analysis of CMB and Radio Maps
  We introduce a new cross-correlation method to detect and verify the
astrophysical origin of Faraday Rotation (FR) in multiwavelength surveys. FR is
well studied in radio astronomy from radio point sources but the $\lambda^{2}$
suppression of FR makes detecting and accounting for this effect difficult at
millimeter and sub-millimeter wavelengths. Therefore statistical methods are
used to attempt to detect FR in the cosmic microwave background (CMB). Most
estimators of the FR power spectrum rely on single frequency data. In contrast,
we investigate the correlation of polarized CMB maps with FR measure maps from
radio point sources. We show a factor of $\sim30$ increase in sensitivity over
single frequency estimators and predict detections exceeding $10\sigma$
significance for a CMB-S4 like experiment. Improvements in observations of FR
from current and future radio polarization surveys will greatly increase the
usefulness of this method.
