Planck intermediate results. L. Evidence of spatial variation of the polarized thermal dust spectral energy distribution and implications for CMB B-mode analysis

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 Benabed, K. and Bernard, J.-P. and Bersanelli, M. and Bielewicz, P. and Bonaldi, A. and Bonavera, L. and Bond, J.R. and Borrill, J. and Bouchet, F.R. and Boulanger, F. and Bracco, A. and Burigana, C. and Calabrese, E. and Cardoso, J.-F. and Chiang, H.C. and Colombo, L.P.L. and Combet, C. and Comis, B. 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 Delouis, J.-M. and Di Valentino, E. and Dickinson, C. and Diego, J.M. and Doré, O. and Douspis, M. and Ducout, A. and Dupac, X. and Dusini, S. and Efstathiou, G. and Elsner, F. and Enßlin, T.A. and Eriksen, H.K. and Falgarone, E. and Fantaye, Y. and Finelli, 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 Giard, M. and González-Nuevo, J. and Górski, K.M. and Gregorio, A. and Gruppuso, A. and Gudmundsson, J.E. and Hansen, F.K. and Helou, G. and Herranz, D. and Hivon, E. and Huang, Z. and Jaffe, A.H. and Jones, W.C. and Keihänen, E. and Keskitalo, R. and Kisner, T.S. and Krachmalnicoff, N. and Kunz, M. and Kurki-Suonio, H. and Lagache, G. and Lähteenmäki, A. and Lamarre, J.-M. and Lasenby, A. and Lattanzi, M. and Lawrence, C.R. and Le Jeune, M. and Levrier, F. and Liguori, M. and Lilje, P.B. and López-Caniego, M. and Lubin, P.M. and Macías-Pérez, J.F. and Maggio, G. and Maino, D. and Mandolesi, N. 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 Melchiorri, A. and Mennella, A. and Migliaccio, M. and Mitra, S. and Miville-Deschênes, M.-A. and Molinari, D. and Moneti, A. and Montier, L. and Morgante, G. and Moss, Adam and Naselsky, P. and Nørgaard-Nielsen, H.U. and Oxborrow, C.A. and Pagano, L. and Paoletti, D. and Partridge, B. and Patrizii, L. and Perdereau, O. and Perotto, L. and Pettorino, V. and Piacentini, F. and Plaszczynski, S. and Polenta, G. and Puget, J.-L. and Rachen, J.P. 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 Sirignano, C. and Sirri, G. and Stanco, L. 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 Vansyngel, F. and Van Tent, F. and Vielva, P. and Wandelt, B.D. and Wehus, I.K. and Zacchei, A. and Zonca, A. (2017) Planck intermediate results. L. Evidence of spatial variation of the polarized thermal dust spectral energy distribution and implications for CMB B-mode analysis. Astronomy & Astrophysics, 599 . A51/1-A51/15. ISSN 1432-0746

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Abstract

The characterization of the Galactic foregrounds has been shown to be the main obstacle in thechallenging quest to detect primordial B-modes in the polarized microwave sky. We make use of the Planck-HFI 2015 data release at high frequencies to place new constraints on the properties of the polarized thermal dust emission at high Galactic latitudes. Here, we specifically study the spatial variability of the dust polarized spectral energy distribution (SED), and its potential impact on the determination of the tensor-to-scalar ratio, r. We use the correlation ratio of the CBBℓ angular power spectra between the 217 and 353 GHz channels as a tracer of these potential variations, computed on different high Galactic latitude regions, ranging from 80% to 20% of the sky. The new insight from Planck data is a departure of the correlation ratio from unity that cannot be attributed to a spurious decorrelation due to the cosmic microwave background, instrumental noise, or instrumental systematics. The effect is marginally detected on each region, but the statistical combination of all the regions gives more than 99% confidence for this variation in polarized dust properties. In addition, we show that the decorrelation increases when there is a decrease in the mean column density of the region of the sky being considered, and we propose a simple power-law empirical model for this dependence, which matches what is seen in the Planck data. We explore the effect that this measured decorrelation has on simulations of the BICEP2-Keck Array/Planck analysis and show that the 2015 constraints from these data still allow a decorrelation between the dust at 150 and 353 GHz that is compatible with our measured value. Finally, using simplified models, we show that either spatial variation of the dust SED or of the dust polarization angle are able to produce decorrelations between 217 and 353 GHz data similar to the values we observe in the data.

Item Type: Article
Additional Information: © ESO, 2017
Keywords: cosmic background radiation; cosmology: observations; submillimeter: ISM; dust, extinction
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Physics and Astronomy
Identification Number: 10.1051/0004-6361/201629164
Depositing User: Eprints, Support
Date Deposited: 02 May 2017 12:02
Last Modified: 13 Oct 2017 00:54
URI: http://eprints.nottingham.ac.uk/id/eprint/42449

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