Estimating the Impact of foregrounds on the Future Detection of Rayleigh
  scattering
  Rayleigh scattering of the cosmic microwave background (CMB) by neutral
hydrogen shortly after recombination leaves frequency-dependent imprints on
intensity and polarization fluctuations. High signal-to-noise observations of
CMB Rayleigh scattering would provide additional insight into the physics of
recombination, including greater constraining power for parameters like the
primordial helium fraction, the light relic density, and the sum of neutrino
masses. However, such a measurement of CMB Rayleigh scattering is challenging
due to the presence of astrophysical foregrounds, which are more intense at the
high frequencies, where the effects of Rayleigh scattering are most prominent.
Here we forecast the detectability of CMB Rayleigh scattering including
foreground removal using blind internal linear combination methods for a set of
near-future surveys. We show that atmospheric effects for ground-based
observatories and astrophysical foregrounds pose a significant hindrance to
detecting CMB Rayleigh scattering with experiments planned for this decade,
though a high-significance measurement should be possible with a future CMB
satellite.
