Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Planck intermediate results. XIX. An overview of the polarized thermal
  emission from Galactic dust   This paper presents the large-scale polarized sky as seen by Planck HFI at
353 GHz, which is the most sensitive Planck channel for dust polarization. We
construct and analyse large-scale maps of dust polarization fraction and
polarization direction, while taking account of noise bias and possible
systematic effects. We find that the maximum observed dust polarization
fraction is high (pmax > 18%), in particular in some of the intermediate dust
column density (AV < 1mag) regions. There is a systematic decrease in the dust
polarization fraction with increasing dust column density, and we interpret the
features of this correlation in light of both radiative grain alignment
predictions and fluctuations in the magnetic field orientation. We also
characterize the spatial structure of the polarization angle using the angle
dispersion function and find that, in nearby fields at intermediate latitudes,
the polarization angle is ordered over extended areas that are separated by
filamentary structures, which appear as interfaces where the magnetic field sky
projection rotates abruptly without apparent variations in the dust column
density. The polarization fraction is found to be anti-correlated with the
dispersion of the polarization angle, implying that the variations are likely
due to fluctuations in the 3D magnetic field orientation along the line of
sight sampling the diffuse interstellar medium.We also compare the dust
emission with the polarized synchrotron emission measured with the Planck LFI,
with low-frequency radio data, and with Faraday rotation measurements of
extragalactic sources. The two polarized components are globally similar in
structure along the plane and notably in the Fan and North Polar Spur regions.
A detailed comparison of these three tracers shows, however, that dust and
cosmic rays generally sample different parts of the line of sight and confirms
that much of the variation observed in the Planck data is due to the 3D
structure of the magnetic field.

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The categories of this paper are: cs
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The categories of this paper are: bayes-an
31
The categories of this paper are: ao-sci
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The categories of this paper are: nucl-ex
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The categories of this paper are: nlin
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The categories of this paper are: math
34
The categories of this paper are: chem-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: dg-ga
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The categories of this paper are: funct-an
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The categories of this paper are: alg-geom
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The categories of this paper are: atom-ph
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The categories of this paper are: eess
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The categories of this paper are: plasm-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: chao-dyn