Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Parsec-scale Properties of eight Fanaroff-Riley Type 0 Radio Galaxies   We report the high-resolution radio observations of eight Fanaroff-Riley type
0 radio galaxies (FR 0s), selected from the published FR 0 sample. These
observations were carried out with the Very Long Baseline Array (VLBA) and
European VLBI Network (EVN) at frequencies of 5 and 8 GHz with a highest
resolution of 0.6 mas. All eight sources show compact structures on projected
physical sizes of 0.3-10 parsec. Six sources show a two-sided structure and two
sources show a one-sided jet structure. J1025+1022 shows an X-shaped jet
structure, which could result from a reorientation of the jet axis due to a
restart of the central engine or a projection of a highly curved inner jet, but
more studies are needed to examine these scenarios. Proper motions for 22 jet
components of the eight sources are determined to be between -0.08 c and 0.51
c. Although most of the sources exhibit flat spectra, other observed
characteristics, such as, low-amplitude flux density variations, low jet proper
motion speeds, and symmetric two-sided jet structures, tend to support that the
pc-scale FR 0 jets are mildly relativistic with lower bulk Lorentz factors and
larger viewing angles.

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The categories of this paper are: acc-phys
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The categories of this paper are: hep-ex
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
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The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: patt-sol
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The categories of this paper are: quant-ph
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The categories of this paper are: funct-an
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The categories of this paper are: nlin
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The categories of this paper are: stat
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The categories of this paper are: nucl-ex
1
The categories of this paper are: cs