1. Planck intermediate results XXXII. The relative orientation between the magnetic field and structures traced by interstellar dust
- Author
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Adam, R, Ade, PAR, Aghanim, N, Alves, MIR, Arnaud, M, Arzoumanian, D, Ashdown, M, Aumont, J, Baccigalupi, C, Banday, AJ, Barreiro, RB, Bartolo, N, Battaner, E, Benabed, K, Benoit-Levy, A, Bernard, J-P, Bersanelli, M, Bielewicz, P, Bonaldi, A, Bonavera, L, Bond, JR, Borrill, J, Bouchet, FR, Boulanger, F, Bracco, A, Burigana, C, Butler, RC, Calabrese, E, Cardoso, J-F, Catalano, A, Chamballu, A, Chiang, HC, Christensen, PR, Colombi, S, Colombo, LPL, Combet, C, Couchot, F, Crill, BP, Curto, A, Cuttaia, F, Danese, L, Davies, RD, Davis, RJ, de Bernardis, P, de Rosa, A, de Zotti, G, Delabrouillel, J, Dickinson, C, Diego, JM, Dole, H, Donzelli, S, Dore, O, Douspis, M, Ducout, A, Dupac, X, Efstathiou, G, Elsner, F, Ensslin, TA, Eriksen, HK, Falgarone, E, Ferriere, K, Finelli, F, Forni, O, Frailis, M, Fraisse, AA, Franceschi, E, Frejse, A, Galeotta, S, Gai, S, Ganga, K, Ghosh, T, Giard, M, Gjerlow, E, Gonzalez-Nuevo, J, Gorski, KM, Gregorio, A, Gruppuso, A, Guillet, V, Hansen, K, Hanson, D, Harrison, DL, Henrot-Versille, S, Hernandez-Monteagudo, C, Herranz, D, Hildebrandt, SR, Hivon, E, Hobson, M, Holmes, WA, Hovest, W, Huffenberger, KM, Hurier, G, Jaffe, AH, Jaffe, TR, Jones, WC, Juvela, M, Keihanen, E, Keskitalo, R, Kisner, TS, Kneiss, R, and Knoche, J
- Subjects
ISM: clouds ,ISM: magnetic fields ,ISM: structure ,magnetohydrodynamics ,polarization ,turbulence ,astro-ph.GA ,Astronomical and Space Sciences ,Astronomy & Astrophysics - Abstract
The role of the magnetic field in the formation of the filamentary structuresobserved in the interstellar medium (ISM) is a debated topic. The Planckall-sky maps of linearly polarized emission from dust at 353GHz provide therequired combination of imaging and statistics to study the correlation betweenthe structures of the Galactic magnetic field and of interstellar matter, bothin the diffuse ISM and in molecular clouds. The data reveal structures, orridges, in the intensity map with counterparts in the Stokes Q and/or U maps.We focus on structures at intermediate and high Galactic latitudes with columndensity from $10^{20}$ to $10^{22}$ cm$^{-2}$. We measure the magnetic fieldorientation on the plane of the sky from the polarization data, and present analgorithm to estimate the orientation of the ridges from the dust intensitymap. We use analytical models to account for projection effects. Comparingpolarization angles on and off the structures, we estimate the mean ratiobetween the strengths of the turbulent and mean components of the magneticfield to be between 0.6 and 1.0, with a preferred value of 0.8. We find thatthe ridges are preferentially aligned with the magnetic field measured on thestructures. This trend becomes more striking for increasing polarizationfraction and decreasing column density. We interpret the increase of alignmentwith polarization fraction as a consequence of projections effects. Thedecrease of alignment for high column density is not due to a loss ofcorrelation between the structures and the geometry of the magnetic field. Inmolecular complexes, we observe structures perpendicular to the magnetic field,which cannot be accounted for by projection effects. We discuss our results inthe context of models and MHD simulations, which describe the formation ofstructures in the magnetized ISM.
- Published
- 2016