B polarization of the CMB from Faraday rotation
- Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque S/N, 1900 La Plata (Argentina)
We study the effect of Faraday rotation due to a uniform magnetic field on the polarization of the cosmic microwave background. Scalar fluctuations give rise only to parity-even E-type polarization of the cosmic microwave background. However in the presence of a magnetic field, a nonvanishing parity-odd B-type polarization component is produced through Faraday rotation. We derive the exact solution for the E and B modes generated by scalar perturbations including the Faraday rotation effect of a uniform magnetic field, and evaluate their cross correlations with temperature anisotropies. We compute the angular autocorrelation function of the B-modes in the limit that the Faraday rotation is small. We find that uniform primordial magnetic fields of present strength around B{sub 0}=10{sup -9} G rotate E-modes into B-modes with amplitude comparable to those due to the weak gravitational lensing effect at frequencies around {nu}=30 GHz. The strength of B-modes produced by Faraday rotation scales as B{sub 0}/{nu}{sup 2}. We evaluate also the depolarizing effect of Faraday rotation upon the cross correlation between temperature anisotropy and E-type polarization.
- OSTI ID:
- 20705191
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 70, Issue 6; Other Information: DOI: 10.1103/PhysRevD.70.063003; (c) 2004 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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