Planck 2018 results. XII. Galactic astrophysics using polarized dust emission
Creators: name: Planck Collaboration
name: Aghanim, N.
name: Akrami, Y.
name: Alves, M. I. R.
name: Ashdown, M.
name: Aumont, J.
name: Baccigalupi, C.
name: Ballardini, M.
name: Banday, A. J.
name: Barreiro, R. B.
name: Bartolo, N.
name: Basak, S.
name: Benabed, K.
name: Bernard, J. -P.
name: Bersanelli, M.
name: Bielewicz, P.
name: Bock, J. J.
name: Bond, J. R.
name: Borrill, J.
name: Bouchet, F. R.
name: Boulanger, F.
name: Bracco, A.
name: Bucher, M.
name: Burigana, C.
name: Calabrese, E.
name: Cardoso, J. -F.
name: Carron, J.
name: Chary, R. -R.
name: Chiang, H. C.
name: Colombo, L. P. L.
name: Combet, C.
name: Crill, B. P.
name: Cuttaia, F.
name: de Bernardis, P.
name: de Zotti, G.
name: Delabrouille, J.
name: Delouis, J. -M.
name: Di Valentino, E.
name: Dickinson, C.
name: Diego, J. M.
name: Doré, O.
name: Douspis, M.
name: Ducout, A.
name: Dupac, X.
name: Efstathiou, G.
name: Elsner, F.
name: Enßlin, T. A.
name: Eriksen, H. K.
name: Falgarone, E.
name: Fantaye, Y.
name: Fernandez-Cobos, R.
name: Ferrière, K.
name: Finelli, F.
name: Forastieri, F.
name: Frailis, M.
name: Fraisse, A. A.
name: Franceschi, E.
name: Frolov, A.
name: Galeotta, S.
name: Galli, S.
name: Ganga, K.
name: Génova-Santos, R. T.
name: Gerbino, M.
name: Ghosh, T.
name: González-Nuevo, J.
name: Górski, K. M.
name: Gratton, S.
name: Green, G.
name: Gruppuso, A.
name: Gudmundsson, J. E.
name: Guillet, V.
name: Handley, W.
name: Hansen, F. K.
name: Helou, G.
name: Herranz, D.
name: Hivon, E.
name: Huang, Z.
name: Jaffe, A. H.
name: Jones, W. C.
name: Keihänen, E.
name: Keskitalo, R.
name: Kiiveri, K.
name: Kim, J.
name: Krachmalnicoff, N.
name: Kunz, M.
name: Kurki-Suonio, H.
name: Lagache, G.
name: Lamarre, J. -M.
name: Lasenby, A.
name: Lattanzi, M.
name: Lawrence, C. R.
name: Jeune, M. Le
name: Levrier, F.
name: Liguori, M.
name: Lilje, P. B.
name: Lindholm, V.
name: López-Caniego, M.
name: Lubin, P. M.
name: Ma, Y. -Z.
name: Macías-Pérez, J. F.
name: Maggio, G.
name: Maino, D.
name: Mandolesi, N.
name: Mangilli, A.
name: Marcos-Caballero, A.
name: Maris, M.
name: Martin, P. G.
name: Martínez-González, E.
name: Matarrese, S.
name: Mauri, N.
name: McEwen, J. D.
name: Melchiorri, A.
name: Mennella, A.
name: Migliaccio, M.
name: Miville-Deschênes, M. -A.
name: Molinari, D.
name: Moneti, A.
name: Montier, L.
name: Morgante, G.
name: Moss, A.
name: Natoli, P.
name: Pagano, L.
name: Paoletti, D.
name: Patanchon, G.
name: Perrotta, F.
name: Pettorino, V.
name: Piacentini, F.
name: Polastri, L.
name: Polenta, G.
name: Puget, J. -L.
name: Rachen, J. P.
name: Reinecke, M.
name: Remazeilles, M.
name: Renzi, A.
name: Ristorcelli, I.
name: Rocha, G.
name: Rosset, C.
name: Roudier, G.
name: Rubiño-Martín, J. A.
name: Ruiz-Granados, B.
name: Salvati, L.
name: Sandri, M.
name: Savelainen, M.
name: Scott, D.
name: Sirignano, C.
name: Sunyaev, R.
name: Suur-Uski, A. -S.
name: Tauber, J. A.
name: Tavagnacco, D.
name: Tenti, M.
name: Toffolatti, L.
name: Tomasi, M.
name: Trombetti, T.
name: Valiviita, J.
name: Vansyngel, F.
name: Van Tent, B.
name: Vielva, P.
name: Villa, F.
name: Vittorio, N.
name: Wandelt, B. D.
name: Wehus, I. K.
name: Zacchei, A.
name: Zonca, A.
Publisher: name: arXiv
Year: 2018
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We present 353 GHz full-sky maps of the polarization fraction $p$, angle $ψ$, and dispersion of angles $S$ of Galactic dust thermal emission produced from the 2018 release of Planck data. We confirm that the mean and maximum of $p$ decrease with increasing $N_H$. The uncertainty on the maximum polarization fraction, $p_\mathrm{max}=22.0$% at 80 arcmin resolution, is dominated by the uncertainty on the zero level in total intensity. The observed inverse behaviour between $p$ and $S$ is interpreted with models of the polarized sky that include effects from only the topology of the turbulent Galactic magnetic field. Thus, the statistical properties of $p$, $ψ$, and $S$ mostly reflect the structure of the magnetic field. Nevertheless, we search for potential signatures of varying grain alignment and dust properties. First, we analyse the product map $S \times p$, looking for residual trends. While $p$ decreases by a factor of 3--4 between $N_H=10^{20}$ cm$^{-2}$ and $N_H=2\times 10^{22}$ cm$^{-2}$, $S \times p$ decreases by only about 25%, a systematic trend observed in both the diffuse ISM and molecular clouds. Second, we find no systematic trend of $S \times p$ with the dust temperature, even though in the diffuse ISM lines of sight with high $p$ and low $S$ tend to have colder dust. We also compare Planck data with starlight polarization in the visible at high latitudes. The agreement in polarization angles is remarkable. Two polarization emission-to-extinction ratios that characterize dust optical properties depend only weakly on $N_H$ and converge towards the values previously determined for translucent lines of sight. We determine an upper limit for the polarization fraction in extinction of 13%, compatible with the $p_\mathrm{max}$ observed in emission. These results provide strong constraints for models of Galactic dust in diffuse gas.
description: Accepted for publication in Astronomy &amp; Astrophysics