Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Radio interferometric observations of two core-dominated triple radio
  sources at z>3   Aims. We selected two radio quasars (J1036+1326 and J1353+5725) based on
their 1.4-GHz radio structure, which is dominated by a bright central core and
a pair of weaker and nearly symmetric lobes at ~10" angular separation. They
are optically identified in the Sloan Digital Sky Survey (SDSS) at
spectroscopic redshifts z>3. We investigate the possibility that their
core-dominated triple morphology can be a sign of restarted radio activity in
these quasars, involving a significant repositioning of the radio jet axis.
Methods. We present the results of high-resolution radio imaging observations
of J1036+1326 and J1353+5725, performed with the European Very Long Baseline
Interferometry (VLBI) Network (EVN) at 1.6 GHz. These data are supplemented by
archive observations from the Very Large Array (VLA).We study the large- and
small-scale radio structures and the brightness temperatures, then estimate
relativistic beaming parameters. Results. We show that the central emission
region of these two high-redshift, core-dominated triple sources is compact but
resolved at ~10 milli-arcsecond resolution. We find that it is not necessary to
invoke large misalignment between the VLBI jet and the large-scale radio
structure to explain the observed properties of the sources.

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The categories of this paper are: stat
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The categories of this paper are: gr-qc
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The categories of this paper are: econ
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The categories of this paper are: mtrl-th
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The categories of this paper are: adap-org
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The categories of this paper are: q-fin
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The categories of this paper are: physics
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The categories of this paper are: quant-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: cs
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The categories of this paper are: patt-sol
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The categories of this paper are: solv-int
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-ex