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Cosmic microwave background polarization constraints on radiative feedback

Authors

  • C. Burigana,

    Corresponding author
    1. INAF–IASF Bologna, Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna, Istituto Nazionale di Astrofisica, via Gobetti 101, I-40129 Bologna, Italy
    2. Dipartimento di Fisica, Università degli Studi di Ferrara, via Saragat 1, I-44100 Ferrara, Italy
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  • L. A. Popa,

    Corresponding author
    1. INAF–IASF Bologna, Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna, Istituto Nazionale di Astrofisica, via Gobetti 101, I-40129 Bologna, Italy
    2. Institute for Space Sciences, Bucharest-Magurele, Str. Atomostilor, 409, Po Box Mg-23, Ro-077125, Romania
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  • R. Salvaterra,

    Corresponding author
    1. Dipartimento di Fisica G. Occhialini, Università degli Studi di Milano Bicocca, Piazza della Scienza 3, I-20126 Milano, Italy
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  • R. Schneider,

    Corresponding author
    1. INAF – Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, I-50125 Firenze, Italy
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  • T. Roy Choudhury,

    Corresponding author
    1. Institute of Astronomy, Madingley Road, Cambridge CB3 0HA
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  • A. Ferrara

    Corresponding author
    1. SISSA/International School for Advanced Studies, Via Beirut 4, I-34100 Trieste, Italy
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E-mail: burigana@iasfbo.inaf.it (CB); lpopa@venus.nipne.ro (LAP); salvaterra@mib.infn.it (RS); raffa@arcetri.astro.it (RS); chou@ast.cam.ac.uk (TRC); ferrara@sissa.it (AF)

ABSTRACT

We compute the imprints left on the cosmic microwave background (CMB) by two cosmic reionization models consistent with current observations but characterized by alternative radiative feedback prescriptions (suppression and filtering) resulting in a different suppression of star formation in low-mass haloes. The models imply different ionization and thermal histories and 21-cm background signals. The derived Comptonization, u, and free–free distortion, yB, parameters are below current observational limits for both models. However, the value of u≃ 1.69 × 10−7 (≃9.65 × 10−8) for the suppression (filtering) model is in the detectability range of the next generation of CMB spectrum experiments. Through, the dedicated Boltzmann code cmbfast, modified to include the above ionization histories, we compute the CMB angular power spectrum (APS) of the TT, TE and EE modes. For the EE mode, the differences between these models are significantly larger than the cosmic and sampling variance over the multipole range ℓ∼ 5–15, leaving a good chance of discriminating between these feedback mechanisms with forthcoming/future CMB polarization experiments. The main limitations come from foreground contamination: it should be subtracted at per cent level in terms of APS, a result potentially achievable by novel component separation techniques and mapping of Galactic foreground.

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