Bibcode
Planck Collaboration; Adam, R.; Ade, P. A. R.; Aghanim, N.; Arnaud, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Bartolo, N.; Battaner, E.; Benabed, K.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bracco, A.; Bucher, M.; Burigana, C.; Butler, R. C.; Calabrese, E.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chary, R.-R.; Chiang, H. C.; Christensen, P. R.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Combet, C.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Dickinson, C.; Diego, J. M.; Dolag, K.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dunkley, J.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Falgarone, E.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Frejsel, A.; Galeotta, S.; Galli, S.; Ganga, K.; Ghosh, T.; Giard, M.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Guillet, V.; Hansen, F. K.; Hanson, D.; Harrison, D. L.; Helou, G.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hivon, E.; Hobson, M.; Holmes, W. A.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R. et al.
Bibliographical reference
Astronomy and Astrophysics, Volume 586, id.A133, 25 pp.
Advertised on:
2
2016
Journal
Citations
422
Refereed citations
365
Description
The polarized thermal emission from diffuse Galactic dust is the main
foreground present in measurements of the polarization of the cosmic
microwave background (CMB) at frequencies above 100 GHz. In this paper
we exploit the uniqueness of the Planck HFI polarization data from 100
to 353 GHz to measure the polarized dust angular power spectra
CℓEE and CℓBB over
the multipole range 40 <ℓ< 600 well away from the Galactic
plane. These measurements will bring new insights into interstellar dust
physics and allow a precise determination of the level of contamination
for CMB polarization experiments. Despite the non-Gaussian and
anisotropic nature of Galactic dust, we show that general statistical
properties of the emission can be characterized accurately over large
fractions of the sky using angular power spectra. The polarization power
spectra of the dust are well described by power laws in multipole,
Cℓ ∝ ℓα, with exponents
αEE,BB = -2.42 ± 0.02. The amplitudes of the
polarization power spectra vary with the average brightness in a way
similar to the intensity power spectra. The frequency dependence of the
dust polarization spectra is consistent with modified blackbody emission
with βd = 1.59 and Td = 19.6 K down to the
lowest Planck HFI frequencies. We find a systematic difference between
the amplitudes of the Galactic B- and E-modes,
CℓBB/CℓEE = 0.5. We
verify that these general properties are preserved towards high Galactic
latitudes with low dust column densities. We show that even in the
faintest dust-emitting regions there are no "clean" windows in the sky
where primordial CMB B-mode polarization measurements could be made
without subtraction of foreground emission. Finally, we investigate the
level of dust polarization in the specific field recently targeted by
the BICEP2 experiment. Extrapolation of the Planck 353 GHz data to 150
GHz gives a dust power 𝒟ℓBB ≡
ℓ(ℓ+1)CℓBB/(2π) of 1.32 ×
10-2 μKCMB2 over the multipole range
of the primordial recombination bump (40 <ℓ< 120); the
statistical uncertainty is ± 0.29 × 10-2
μKCMB2 and there is an additional uncertainty
(+0.28, -0.24) × 10-2 μKCMB2
from the extrapolation. This level is the same magnitude as reported by
BICEP2 over this ℓ range, which highlights the need for assessment
of the polarized dust signal even in the cleanest windows of the sky.