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The seed magnetic field generated during recombination

Fenu, Elisa ; Pitrou, Cyril ; Maartens, Roy

In: Monthly Notices of the Royal Astronomical Society, 2011, vol. 414, no. 3, p. 2354-2366

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    Titre
    • The seed magnetic field generated during recombination
    Auteur
    • Fenu, Elisa. Département de Physique Théorique, Université de Genève, CH-1211 Genève, Switzerland
    • Pitrou, Cyril. Institute of Cosmology & Gravitation, University of Portsmouth, Portsmouth PO1 3FX
    • Maartens, Roy. Institute of Cosmology & Gravitation, University of Portsmouth, Portsmouth PO1 3FX
    Type de document
    • Postprint
    Langue
    • Inglese
    Publié dans
    • Monthly Notices of the Royal Astronomical Society, 2011, vol. 414, no. 3, p. 2354-2366. Blackwell Publishing Ltd
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:299512
    Summary
    Non-linear dynamics creates vortical currents when the tight-coupling approximation between photons and baryons breaks down around the time of recombination. This generates a magnetic field at second order in cosmological perturbations, whose power spectrum is fixed by standard physics, without the need for any ad hoc assumptions. We present the fully general relativistic calculation of the magnetic power spectrum, including the effects of metric perturbations, second-order velocity and photon anisotropic stress, thus generalizing and correcting previous results. We also show that significant magnetogenesis continues to occur after recombination. The power spectrum decays as k4 on large scales, and grows as k0.5 on small scales, down to the limit of our numerical computations, ∼1 Mpc. On cluster scales, the created field has a strength of ∼3 × 10−29 G