Faraday rotation limits on a primordial magnetic field from Wilkinson Microwave Anisotropy Probe five-year data

Tina Kahniashvili, Yurii Maravin, Arthur Kosowsky
2009 Physical Review D  
A primordial magnetic field in the early universe will cause Faraday rotation of the linear polarization of the cosmic microwave background generated via Compton scattering at the surface of last scattering. This rotation induces a non-zero parity-odd (B-mode) polarization component. The Wilkinson Microwave Anisotropy Probe (WMAP) 5-year data puts an upper limit on the magnitude of the B-polarization power spectrum; assuming that the B-polarization signal is totally due to the Faraday rotation
more » ... ffect, the upper limits on the comoving amplitude of a primordial stochastic magnetic field range from 6 × 10^-8 to 2 × 10^-6 G on a comoving length scale of 1 Mpc, depending on the power spectrum of the magnetic field.
doi:10.1103/physrevd.80.023009 fatcat:ruen37wprvap5l5ri3tddfqgey