Bibcode
Planck Collaboration; Aghanim, N.; Alves, M. I. R.; Arzoumanian, D.; Aumont, J.; Baccigalupi, C.; Ballardini, M.; Banday, A. J.; Barreiro, R. B.; Bartolo, N.; Basak, S.; Benabed, K.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bracco, A.; Bucher, M.; Burigana, C.; Calabrese, E.; Cardoso, J.-F.; Chiang, H. C.; Colombo, L. P. L.; Combet, C.; Comis, B.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Di Valentino, E.; Dickinson, C.; Diego, J. M.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Dusini, S.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Falgarone, E.; Fantaye, Y.; Ferrière, K.; Finelli, F.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Frolov, A.; Galeotta, S.; Galli, S.; Ganga, K.; Génova-Santos, R. T.; Gerbino, M.; Ghosh, T.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Guillet, V.; Hansen, F. K.; Helou, G.; Henrot-Versillé, S.; Herranz, D.; Hivon, E.; Huang, Z.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Krachmalnicoff, N.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Langer, M.; Lasenby, A.; Lattanzi, M.; Le Jeune, M.; Levrier, F.; Liguori, M.; Lilje, P. B.; López-Caniego, M.; Lubin, P. M. et al.
Bibliographical reference
Astronomy and Astrophysics, Volume 596, id.A105, 15 pp.
Advertised on:
12
2016
Journal
Citations
58
Refereed citations
55
Description
Using data from the Planck satellite, we study the statistical
properties of interstellar dust polarization at high Galactic latitudes
around the south pole (b < -60°). Our aim is to advance the
understanding of the magnetized interstellar medium (ISM), and to
provide a modelling framework of the polarized dust foreground for use
in cosmic microwave background (CMB) component-separation procedures. We
examine the Stokes I, Q, and U maps at 353 GHz, and particularly the
statistical distribution of the polarization fraction (p) and angle
(ψ), in order to characterize the ordered and turbulent components
of the Galactic magnetic field (GMF) in the solar neighbourhood. The Q
and U maps show patterns at large angular scales, which we relate to the
mean orientation of the GMF towards Galactic coordinates
(l0,b0) = (70° ± 5°,24°
± 5°). The histogram of the observed p values shows a wide
dispersion up to 25%. The histogram of ψ has a standard deviation of
12° about the regular pattern expected from the ordered GMF. We
build a phenomenological model that connects the distributions of p and
ψ to a statistical description of the turbulent component of the
GMF, assuming a uniform effective polarization fraction (p0)
of dust emission. To compute the Stokes parameters, we approximate the
integration along the line of sight (LOS) as a sum over a set of N
independent polarization layers, in each of which the turbulent
component of the GMF is obtained from Gaussian realizations of a
power-law power spectrum. We are able to reproduce the observed p and
ψ distributions using a p0 value of 26%, a ratio of 0.9
between the strengths of the turbulent and mean components of the GMF,
and a small value of N. The mean value of p (inferred from the fit of
the large-scale patterns in the Stokes maps) is 12 ± 1%. We
relate the polarization layers to the density structure and to the
correlation length of the GMF along the LOS. We emphasize the simplicity
of our model (involving only a few parameters), which can be easily
computed on the celestial sphere to produce simulated maps of dust
polarization. Our work is an important step towards a model that can be
used to assess the accuracy of component-separation methods in present
and future CMB experiments designed to search the B mode CMB
polarization from primordial gravity waves.