Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic Fields in Massive Star-Forming Regions (MagMaR) I. Linear
  Polarized Imaging of the UCHII Region G5.89-0.39   We report 1.2 mm polarized continuum emission observations carried out with
the Atacama Large Millimeter/submillimeter Array (ALMA) toward the high-mass
star formation region G5.89-0.39. The observations show a prominent 0.2 pc
north-south filamentary structure. The UCHII in G5.89-0.39 breaks the filament
in two pieces. Its millimeter emission shows a dusty belt with a mass of 55-115
M$_{\odot}$ and 4,500 au in radius, surrounding an inner part comprising mostly
ionized gas with a dust emission only accounting about 30% of the total
millimeter emission. We also found a lattice of convex arches which may be
produced by dragged dust and gas from the explosive dispersal event involving
the O5 Feldt's star. The north-south filament has a mass between 300-600
M$_{\odot}$ and harbours a cluster of about 20 millimeter envelopes with a
median size and mass of 1700 au and 1.5 M$_{\odot}$, respectively, some of
which are already forming protostars.
  We interpret the polarized emission in the filament as mainly coming from
magnetically aligned dust grains. The polarization fraction is ~4.4% in the
filaments and 2.1% at the shell. The magnetic fields are along the North
Filament and perpendicular to the South Filament. In the Central Shell, the
magnetic fields are roughly radial in a ring surrounding the dusty belt between
4,500 and 7,500 au, similar to the pattern recently found in the surroundings
of Orion BN/KL. This may be an independent observational signpost of explosive
dispersal outflows and should be further investigated in other regions.

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The categories of this paper are: eess
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The categories of this paper are: math
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The categories of this paper are: comp-gas
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The categories of this paper are: atom-ph
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The categories of this paper are: q-alg
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The categories of this paper are: acc-phys
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The categories of this paper are: chao-dyn
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The categories of this paper are: adap-org
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The categories of this paper are: solv-int
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The categories of this paper are: q-fin
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The categories of this paper are: quant-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: funct-an
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The categories of this paper are: hep-th
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The categories of this paper are: stat
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The categories of this paper are: plasm-ph