Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic fields in the Southern Galactic Plane Survey   The Southern Galactic Plane Survey (SGPS) is a 1.4 GHz radio polarization and
HI survey in a large part of the inner Galactic plane at a resolution of about
an arcmin. Depolarization and Faraday rotation of polarized radiation from
diffuse Galactic synchrotron emission, pulsars, and extragalactic sources can
be used to infer information about the strength and structure of the Galactic
magnetic field. Here, we discuss science results of the polarization data from
the SGPS. We show from statistical analysis of rotation measures of polarized
extragalactic sources that fluctuations in the magneto-ionized medium of the
spiral arms are probably mainly caused by HII regions, while the rotation
measure fluctuations in the interarm regions may be connected to the
interstellar turbulent cascade. Furthermore, the variations of rotation measure
with Galactic longitude enable modeling of the large-scale component of the
Galactic magnetic field, including determination of the number and location of
magnetic field reversals. Finally, the SGPS is an excellent way to study
subparsec-scale structure in the ionized ISM by way of depolarization studies
in HII regions.

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The categories of this paper are: funct-an
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The categories of this paper are: math-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: supr-con
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The categories of this paper are: nucl-th
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The categories of this paper are: adap-org
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The categories of this paper are: econ
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The categories of this paper are: plasm-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: alg-geom
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The categories of this paper are: patt-sol
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The categories of this paper are: ao-sci
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The categories of this paper are: q-bio