Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Intrinsic Differences in the Inner Jets of High- and Low-Optically
  Polarized Radio Quasars   A significant fraction of compact radio-loud quasars display most of the
characteristics of relativistically beamed, high-optical polarization blazars,
yet are weakly polarized in the optical regime. We have used the VLBA at 22 and
43 GHz to look for differences in the parsec-scale magnetic field structures of
18 high- and low-optically polarized, compact radio-loud quasars (HPQs and
LPRQs, respectively). We find a strong correlation between the polarization
level of the unresolved parsec-scale radio core at 43 GHz and overall optical
polarization of the source, which suggests a common (possibly co-spatial)
origin for the emission at these two wavelengths. The magnetic fields of the
polarized 43 GHz radio cores are aligned roughly transverse to the jet axis.
Similar orientations are seen in the optical, suggesting that the polarized
flux at both wavelengths is due to one or more strong transverse shocks located
very close to the base of the jet. In LPRQs, these shocks appear to be weak
near the core, and gradually increase in strength down the jet. The LPRQs in
our sample tend to have less luminous radio cores than the HPQs, and jet
components with magnetic fields predominantly parallel to the flow. The
components in HPQ jets, on the other hand, tend to have transverse alignments.
These differences cannot be accounted for by a simple model in which HPQs and
LPRQs are the same type of object, seen at different angles to the line of
sight. A more likely scenario is that LPRQs represent a quiescent phase of
blazar activity, in which the inner jet flow does not undergo strong shocks.

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The categories of this paper are: physics
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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: alg-geom
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The categories of this paper are: hep-lat
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-th
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The categories of this paper are: comp-gas
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-th
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The categories of this paper are: cs
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ph
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The categories of this paper are: stat
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-bio