2014/09/30 by R. Adam, Planck Collaboration, P. A. R. Ade +239 · 2 voices · 2 citations
Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Experimental and Theoretical Physics Studies #Quantum Electrodynamics and Casimir Effect #astro-ph.CO
paper · pdf · doi:10.1051/0004-6361/201425034
published as A&A 586, A133 (2016) · 25 pages, 25 figures, accepted in A&A
arxiv created 2014/12/08 · openalex publication_date 2015/01/13 · arxiv updated 2016/02/10 · openalex created_date 2022/08/20 · openalex updated_date 2026/08/04
The polarized thermal emission from Galactic dust is the main foreground present in measurements of the polarization of the cosmic microwave background (CMB) at frequencies above 100GHz. We exploit the Planck HFI polarization data from 100 to 353GHz to measure the dust angular power spectra C_ℓEE,BB over the range 40<ℓ<600 well away from the Galactic plane. These will bring new insights into interstellar dust physics and a precise determination of the level of contamination for CMB polarization experiments. We show that statistical properties of the emission can be characterized over large fractions of the sky using C_ℓ. For the dust, they are well described by power laws in ℓ with exponents αEE,BB=-2.42±0.02. The amplitudes of the polarization C_ℓ vary with the average brightness in a way similar to the intensity ones. The dust polarization frequency dependence is consistent with modified blackbody emission with βd=1.59 and Td=19.6K. We find a systematic ratio between the amplitudes of the Galactic B- and E-modes of 0.5. We show that even in the faintest dust-emitting regions there are no "clean" windows where primordial CMB B-mode polarization could be measured without subtraction of dust emission. Finally, we investigate the level of dust polarization in the BICEP2 experiment field. Extrapolation of the Planck 353GHz data to 150GHz gives a dust power ℓ(ℓ+1)C_ℓBB/(2π) of 1.32×10-2μKCMB2 over the 40<ℓ<120 range; the statistical uncertainty is ±0.29 and there is an additional uncertainty (+0.28,-0.24) from the extrapolation, both in the same units. This 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.