Planck intermediate results. XLVII. Planck constraints on reionization history

Adam, R. and Aghanim, N. and Ashdown, M. and Aumont, J. and Baccigalupi, C. and Ballardini, M. and Banday, A.J. and Barreiro, R.B. and Bartolo, N. and Basak, S. and Battye, R. and Benabed, K. and Bernard, J.-P. and Bersanelli, M. and Bielewicz, P. and Bock, J.J. and Bonaldi, A. and Bonavera, L. and Bond, J.R. and Borrill, J. and Bouchet, F.R. and Boulanger, F. and Bucher, M. and Burigana, C. and Calabrese, E. and Cardoso, J.-F. and Carron, J. and Chiang, H.C. and Colombo, L.P.L. and Combet, C. and Comis, B. and Couchot, F. and Coulais, A. and Crill, B.P. and Curto, A. and Cuttaia, F. and Davis, R.J. and de Bernardis, P. and de Rosa, A. and de Zotti, G. and Delabrouille, J. and Di Valentino, E. and Dickinson, C. and Diego, J.M. and Doré, O. and Douspis, M. and Ducout, A. and Dupac, X. and Elsner, F. and Enßlin, T.A. and Eriksen, H.K. and Falgarone, E. and Fantaye, Y. and Finelli, F. and Forastieri, F. and Frailis, M. and Fraisse, A.A. and Franceschi, E. and Frolov, A. and Galeotta, S. and Galli, S. and Ganga, K. and Génova-Santos, R.T. and Gerbino, M. and Ghosh, T. and González-Nuevo, J. and Górski, K.M. and Gruppuso, A. and Gudmundsson, J.E. and Hansen, F.K. and Helou, G. and Henrot-Versillé, S. and Herranz, D. and Hivon, E. and Huang, Z. and Ilić, S. and Jaffe, A.H. and Jones, W.C. and Keihänen, E. and Keskitalo, R. and Kisner, T.S. and Knox, L. and Krachmalnicoff, N. and Kunz, M. and Kurki-Suonio, H. and Lagache, G. and Lähteenmäki, A. and Lamarre, J.-M. and Langer, M. and Lasenby, A. and Lattanzi, M. and Lawrence, C.R. and Le Jeune, M. and Levrier, F. and Lewis, A. and Liguori, M. and Lilje, P.B. and López-Caniego, M. and Ma, Y.-Z. and Macías-Pérez, J.F. and Maggio, G. and Mangilli, A. and Maris, M. and Martin, P.G. and Martínez-González, E. and Matarrese, S. and Mauri, N. and McEwen, J.D. and Meinhold, P.R. and Melchiorri, A. and Mennella, A. and Migliaccio, M. and Miville-Deschênes, M.-A. and Molinari, D. and Moneti, A. and Montier, L. and Morgante, G. and Moss, Adam and Naselsky, P. and Natoli, P. and Oxborrow, C.A. and Pagano, L. and Paoletti, D. and Partridge, B. and Patanchon, G. and Patrizii, L. and Perdereau, O. and Perotto, L. and Pettorino, V. and Piacentini, F. and Plaszczynski, S. and Polastri, L. and Polenta, G. and Puget, J.-L. and Rachen, J.P. and Racine, B. and Reinecke, M. and Remazeilles, M. and Renzi, A. and Rocha, G. and Rossetti, M. and Roudier, G. and Rubiño-Martín, J.A. and Ruiz-Granados, B. and Salvati, L. and Sandri, M. and Savelainen, M. and Scott, D. and Sirri, G. and Sunyaev, R. and Suur-Uski, A.-S. and Tauber, J.A. and Tenti, M. and Toffolatti, L. and Tomasi, M. and Tristram, M. and Trombetti, T. and Valiviita, J. and Van Tent, F. and Vielva, P. and Villa, F. and Vittorio, N. and Wandelt, B.D. and Wehus, I.K. and White, M. and Zacchei, A. and Zonca, A. (2016) Planck intermediate results. XLVII. Planck constraints on reionization history. Astronomy & Astrophysics, 596 . A108/1-A108/19. ISSN 0004-6361

[img]
Preview
PDF - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Download (1MB) | Preview

Abstract

We investigate constraints on cosmic reionization extracted from the Planck cosmic microwave background (CMB) data. We combine the Planck CMB anisotropy data in temperature with the low-multipole polarization data to fit ΛCDM models with various parameterizations of the reionization history. We obtain a Thomson optical depth τ = 0.058 ± 0.012 for the commonly adopted instantaneous reionization model. This confirms, with data solely from CMB anisotropies, the low value suggested by combining Planck 2015 results with other data sets, and also reduces the uncertainties. We reconstruct the history of the ionization fraction using either a symmetric or an asymmetric model for the transition between the neutral and ionized phases. To determine better constraints on the duration of the reionization process, we also make use of measurements of the amplitude of the kinetic Sunyaev-Zeldovich (kSZ) effect using additional information from the high-resolution Atacama Cosmology Telescope and South Pole Telescope experiments. The average redshift at which reionization occurs is found to lie between z = 7.8 and 8.8, depending on the model of reionization adopted. Using kSZ constraints and a redshift-symmetric reionization model, we find an upper limit to the width of the reionization period of Δz < 2.8. In all cases, we find that the Universe is ionized at less than the 10% level at redshifts above z ≃ 10. This suggests that an early onset of reionization is strongly disfavoured by the Planck data. We show that this result also reduces the tension between CMB-based analyses and constraints from other astrophysical sources.

Item Type: Article
Keywords: cosmic background radiation; dark ages, reionization, first stars; polarization
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Physics and Astronomy
Identification Number: 10.1051/0004-6361/201628897
Depositing User: Eprints, Support
Date Deposited: 28 Apr 2017 08:29
Last Modified: 29 Apr 2017 15:39
URI: http://eprints.nottingham.ac.uk/id/eprint/42388

Actions (Archive Staff Only)

Edit View Edit View