Faraday rotation of the cosmic microwave background polarization by a stochastic magnetic field
- Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854 (United States)
- Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, Kansas 66506 (United States) and Center for Plasma Astrophysics, Abastumani Astrophysical Observatory, 2A Kazbegi Avenue, GE-0160 Tbilisi (Georgia)
- Department of Theoretical Physics, A. Razmadze Mathematical Institute, GE-0193 Tbilisi (Georgia)
- Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, Kansas 66506 (United States)
A primordial cosmological magnetic field induces Faraday rotation of the cosmic microwave background polarization. This rotation produces a curl-type polarization component even when the unrotated polarization possesses only gradient-type polarization, as expected from scalar density perturbations. We compute the angular power spectrum of curl-type polarization arising from small Faraday rotation due to a weak stochastic primordial magnetic field with a power-law power spectrum. The induced polarization power spectrum peaks at arc minute angular scales. Faraday rotation is one of the few cosmological sources of curl-type polarization, along with primordial tensor perturbations, gravitational lensing, and the vector and tensor perturbations induced by magnetic fields; the Faraday rotation signal peaks on significantly smaller angular scales than any of these, with a power spectrum amplitude which can be comparable to that from gravitational lensing. Prospects for detection are briefly discussed.
- OSTI ID:
- 20705986
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 71, Issue 4; Other Information: DOI: 10.1103/PhysRevD.71.043006; (c) 2005 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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