Ade, P.A.R. and Atrio-Barandela, F. and Aumont, J. and Baccigalupi, C. and Banday, A.J. and Barreiro, R.B. and Battaner, E. and Benabed, K. and Benoit-Lévy, A. and Bernard, J.-P. and Bersanelli, M. and Bielewicz, P. and Bock, J.J. and Bond, J.R. and Borrill, J. and Bouchet, F.R. and Boulanger, F. and Burigana, C. and Cardoso, J.-F. and Catalano, A. and Chamballu, A. and Chiang, H.C. and Colombo, L.P.L. and Combet, C. and Couchot, F. 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 Zotti, G. and Delabrouille, J. and Desert, F.-X. and Dickinson, C. and Diego, J.M. and Donzelli, S. and Dore, O. and Douspis, M. and Dunkley, J. and Dupac, X. and Enßlin, T.A. and Eriksen, H.K. and Falgarone, E. and Finelli, F. and Forni, O. and Frailis, M. and Fraisse, A.A. and Franceschi, E. and Galeotta, S. and Ganga, K. and Ghosh, T. and Giard, M. and Gonzalez-Nuevo, J. and Gorski, K.M. and Gregorio, A. and Gruppuso, A. and Guillet, V. and Hansen, F.K. and Harrison, D.L. and Helou, G. and Hernandez-Monteagudo, C. and Hildebrandt, S.R. and Hivon, E. and Hobson, M. and Holmes, W.A. and Hornstrup, A. and Jaffe, A.H. and Jaffe, T.R. and Jones, W.C. and Keihanen, E. and Keskitalo, R. and Kisner, T.S. and Kneissl, R. and Knoche, J. and Kunz, M. and Kurki-Suonio, H. and Lagache, G. and Lamarre, J.-M. and Lasenby, A. and Lawrence, C.R. and Leahy, J.P. and Leonardi, R. and Levrier, F. and Liguori, M. and Lilje, P.B. and Linden-Vornle, M. and Lopez-Caniego, M. and Lubin, P.M. and Macias-Perez, J.F. and Maffei, B. and Magalhães, A.M. and Maino, D. and Mandolesi, N. and Maris, M. and Marshall, D.J. and Martin, P.G. and Martinez-Gonzalez, E. and Masi, S. and Matarrese, S. and Mazzotta, P. and Melchiorri, A. and Mendes, L. and Mennella, A. and Migliaccio, M. and Miville-Deschenes, M.-A. and Moneti, A. and Montier, L. and Morgante, G. and Mortlock, D. and Munshi, D. and Murphy, J.Anthony and Naselsky, P. and Nati, F. and Natoli, P. and Netterfield, C.B. and Noviello, F. and Novikov, D. and Novikov, I. and Oppermann, N. and Oxborrow, C.A. and Pagano, L. and Pajot, F. and Paoletti, D. and Pasian, F. and Perdereau, O. and Perotto, L. and Perrotta, F. and Piacentini, F. and Pietrobon, D. and Plaszczynski, S. and Pointecouteau, E. and Polenta, G. and Popa, L. and Pratt, G.W. and Rachen, J.P. and Reach, W.T. and Reinecke, M. and Remazeilles, M. and Renault, C. and Ricciardi, S. and Riller, T. and Ristorcelli, I. and Rocha, G. and Rosset, C. and Roudier, G. and Rubino-Martin, J.A. and Rusholme, B. and Salerno, E. and Sandri, M. and Savini, G. and Scott, D. and Spencer, L. and Stolyarov, V. and Stompor, R. and Sudiwala, 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 Alves, M.I.R. and Aniano, G. and Armitage-Caplan, C. and Arnaud, M. and Tucci, M. and Valenziano, L. and Valiviita, J. and Van Tent, B. and Vielva, P. and Villa, F. and Wandelt, B.D. and Zacchei, A. and Zonca, A. (2015) Planck intermediate results. XXII. Frequency dependence of thermal emission from Galactic dust in intensity and polarization. Astronomy & Astrophysics, 576 (A107). ISSN 0004-6361

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Abstract

Planck has mapped the intensity and polarization of the sky at microwave frequencies with unprecedented sensitivity. We use these data to characterize the frequency dependence of dust emission. We make use of the Planck 353 GHz I, Q, and U Stokes maps as dust templates, and cross-correlate them with the Planck and WMAP data at 12 frequencies from 23 to 353 GHz, over circular patches with 10° radius. The cross-correlation analysis is performed for both intensity and polarization data in a consistent manner. The results are corrected for the chance correlation between the templates and the anisotropies of the cosmic microwave background. We use a mask that focuses our analysis on the diffuse interstellar medium at intermediate Galactic latitudes. We determine the spectral indices of dust emission in intensity and polarization between 100 and 353 GHz, for each sky patch. Both indices are found to be remarkably constant over the sky. The mean values, 1.59 ± 0.02 for polarization and 1.51 ± 0.01 for intensity, for a mean dust temperature of 19.6 K, are close, but significantly different (3.6σ). We determine the mean spectral energy distribution (SED) of the microwave emission, correlated with the 353 GHz dust templates, by averaging the results of the correlation over all sky patches. We find that the mean SED increases for decreasing frequencies at ν< 60 GHz for both intensity and polarization. The rise of the polarization SED towards low frequencies may be accounted for by a synchrotron component correlated with dust, with no need for any polarization of the anomalous microwave emission. We use a spectral model to separate the synchrotron and dust polarization and to characterize the spectral dependence of the dust polarization fraction. The polarization fraction (p) of the dust emission decreases by (21 ± 6)% from 353 to 70 GHz. We discuss this result within the context of existing dust models. The decrease in p could indicate differences in polarization efficiency among components of interstellar dust (e.g., carbon versus silicate grains). Our observational results provide inputs to quantify and optimize the separation between Galactic and cosmological polarization.

Item Type:	Article
Keywords:	Planck collaboration; polarization; ISM: general; Galaxy: general; radiation mechanisms: general; submillimeter: ISM; infrared: ISM;
Academic Unit:	Faculty of Science and Engineering > Experimental Physics
Item ID:	14115
Identification Number:	https://doi.org/10.1051/0004-6361/201424088
Depositing User:	Dr. Anthony Murphy
Date Deposited:	01 Mar 2021 16:33
Journal or Publication Title:	Astronomy & Astrophysics
Publisher:	EDP Sciences
Refereed:	Yes
URI:	Publisher
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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