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    Planck 2015 results XI. CMB power spectra, likelihoods, and robustness of parameters


    Aghanim, N. and Arnaud, M. and Ashdown, M. and Aumont, J. and Baccigalupi, C. and Banday, A.J. and Barreiro, R.B. and Bartlett, J.G. and Bartolo, N. and Battaner, E. and Benabed, K. and Benoit, A. and Benoit-Lévy, A. 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 Butler, R.C. and Calabrese, E. and Cardoso, J.-F. and Catalano, A. and Challinor, A. and Chiang, H.C. and Christensen, P.R. and Clements, D.L. and Colombo, L.P.L. and Combet, C. and Coulais, A. and Crill, B.P. and Curto, A. and Cuttaia, F. and Danese, L. and Davies, R.D. and Davis, R.J. and De Bernardis, P. and de Rosa, A. and de Zotti, G. and Delabrouille, J. and Desert, F.-X. and Di Valentino, E. and Dickinson, C. and Diego, J.M. and Dolag, K. and Dole, H. and Donzelli, S. and Dore, O. and Douspis, M. and Ducout, A. and Dunkley, J. and Dupac, X. and Efstathiou, G. and Elsner, F. and Enßlin, T.A. and Eriksen, H.K. and Fergusson, J. and Finelli, F. and Forni, O. and Frailis, M. and Fraisse, A.A. and Franceschi, E. and Frejsel, A. and Galeotta, S. and Galli, S. and Ganga, K. and Gauthier, C. and Gerbino, M. and Giard, M. and Gjerløw, E. and Gonzalez-Nuevo, J. and Gorski, K.M. and Gratton, S. and Gregorio, A. and Gruppuso, A. and Gudmundsson, J.E. and Hamann, J. and Hansen, F.K. and Harrison, D. and Helou, G. and Henrot-Versille, S. and Hernandez-Monteagudo, C. and Herranz, D. and Hildebrandt, S.R. and Hivon, E. and Holmes, W.A. and Hornstrup, A. and Huffenberger, K.M. and Hurier, G. and Jaffe, A.H. and Jones, W.C. and Juvela, M. and Keihanen, E. and Keskitalo, R. and Kiiveri, K. and Knoche, J. and Knox, L. and Kunz, M. and Kurki-Suonio, H. and Lagache, G. and Lahteenmaki, A. and Lamarre, J.-M. and Lasenby, A. and Lattanzi, M. and Lawrence, C.R. and Le Jeune, M. and Leonardi, R. and Lesgourgues, J. and Levrier, F. and Lewis, A. and Liguori, M. and Lilje, P.B. and Lilley, M. and Linden-Vornle, M. and Lindholm, V. and Lopez-Caniego, M. and Macias-Perez, J.F. and Maffei, B. and Maggio, G. and Maino, D. and Mandolesi, N. and Mangilli, A. and Maris, M. and Martin, P.G. and Martinez-Gonzalez, E. and Masi, S. and Matarrese, S. and Meinhold, P.R. and Melchiorri, A. and Migliaccio, M. and Millea, M. and Mitra, S. and Miville-Deschenes, M.-A. and Moneti, A. and Montier, L. and Morgante, G. and Mortlock, D. and Mottet, S. and Munshi, D. and Murphy, J.Anthony and Narimani, A. and Naselsky, P. and Nati, F. and Natoli, P. and Noviello, F. and Novikov, D. and Novikov, I. and Oxborrow, C.A. and Paci, F. and Pagano, L. and Pajot, F. and Paoletti, D. and Partridge, B. and Pasian, F. and Patanchon, G. and Pearson, T.J. and Perdereau, O. and Perotto, L. and Pettorino, V. and Piacentini, F. and Piat, M. and Pierpaoli, E. and Pietrobon, D. and Plaszczynski, S. and Pointecouteau, E. and Polenta, G. and Ponthieu, N. and Pratt, G.W. and Prunet, S. and Puget, J.-L. and Rachen, J.P. and Reinecke, M. and Remazeilles, M. and Renault, C. and Renzi, A. and Ristorcelli, I. and Rocha, G. and Rossetti, M. and Roudier, G. and Rouillé d’Orfeuil, B. and Rubino-Martin, J.A. and Rusholme, B. and Salvati, L. and Sandri, M. and Santos, D. and Savelainen, M. and Savini, G. and Scott, D. and Serra, P. and Spencer, L. and Spinelli, M. and Stolyarov, V. and Stompor, R. and Sunyaev, R. and Sutton, D. and Suur-Uski, A.-S. and Sygnet, J.-F. and Tauber, J.A. and Terenzi, L. and Toffolatti, L. and Tomasi, M. and Tristram, M. and Trombetti, T. and Tucci, M. and Tuovinen, J. and Umana, G. and Valenziano, L. and Valiviita, J. and Van Tent, B. and Vielva, P. and Villa, F. and Wade, L.A. and Wandelt, B.D. and Wehus, I. and Yvon, D. and Zacchei, A. and Zonca, A. (2016) Planck 2015 results XI. CMB power spectra, likelihoods, and robustness of parameters. Astronomy & Astrophysics, 594 (A11). ISSN 0004-6361

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    Abstract

    This paper presents the Planck 2015 likelihoods, statistical descriptions of the 2-point correlationfunctions of the cosmic microwave background (CMB) temperature and polarization fluctuations that account for relevant uncertainties, both instrumental and astrophysical in nature. They are based on the same hybrid approach used for the previous release, i.e., a pixel-based likelihood at low multipoles (ℓ< 30) and a Gaussian approximation to the distribution of cross-power spectra at higher multipoles. The main improvements are the use of more and better processed data and of Planck polarization information, along with more detailed models of foregrounds and instrumental uncertainties. The increased redundancy brought by more than doubling the amount of data analysed enables further consistency checks and enhanced immunity to systematic effects. It also improves the constraining power of Planck, in particular with regard to small-scale foreground properties. Progress in the modelling of foreground emission enables the retention of a larger fraction of the sky to determine the properties of the CMB, which also contributes to the enhanced precision of the spectra. Improvements in data processing and instrumental modelling further reduce uncertainties. Extensive tests establish the robustness and accuracy of the likelihood results, from temperature alone, from polarization alone, and from their combination. For temperature, we also perform a full likelihood analysis of realistic end-to-end simulations of the instrumental response to the sky, which were fed into the actual data processing pipeline; this does not reveal biases from residual low-level instrumental systematics. Even with the increase in precision and robustness, the ΛCDM cosmological model continues to offer a very good fit to the Planck data. The slope of the primordial scalar fluctuations, ns, is confirmed smaller than unity at more than 5σ from Planck alone. We further validate the robustness of the likelihood results against specific extensions to the baseline cosmology, which are particularly sensitive to data at high multipoles. For instance, the effective number of neutrino species remains compatible with the canonical value of 3.046. For this first detailed analysis of Planck polarization spectra, we concentrate at high multipoles on the E modes, leaving the analysis of the weaker B modes to future work. At low multipoles we use temperature maps at all Planck frequencies along with a subset of polarization data. These data take advantage of Planck’s wide frequency coverage to improve the separation of CMB and foreground emission. Within the baseline ΛCDM cosmology this requires τ = 0.078 ± 0.019 for the reionization optical depth, which is significantly lower than estimates without the use of high-frequency data for explicit monitoring of dust emission. At high multipoles we detect residual systematic errors in E polarization, typically at the μK2 level; we therefore choose to retain temperature information alone for high multipoles as the recommended baseline, in particular for testing non-minimal models. Nevertheless, the high-multipole polarization spectra from Planck are already good enough to enable a separate high-precision determination of the parameters of the ΛCDM model, showing consistency with those established independently from temperature information alone.

    Item Type: Article
    Keywords: Planck Collaboration; cosmic background radiation; cosmological parameters; cosmology: observations; methods: data analysis; methods: statistical;
    Academic Unit: Faculty of Science and Engineering > Experimental Physics
    Item ID: 14398
    Identification Number: https://doi.org/10.1051/0004-6361/201526926
    Depositing User: Dr. Anthony Murphy
    Date Deposited: 30 Apr 2021 11:10
    Journal or Publication Title: Astronomy & Astrophysics
    Publisher: EDP Sciences
    Refereed: Yes
    URI:

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