Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The genesis of morphologies in extended radio sources: X-shapes,
  off-axis distortions and giant radio sources   We examine relationships between the morphology in double radio sources and
the radio-optical position angle offset--the relative orientation of the radio
axis with respect to the major axis of the host galaxy. The study was done for
a representative sample of radio sources: the nearby (redshift z < 0.5) 3CRR
sources, and separately for samples of giant radio sources and X-shaped radio
sources. We find that radio morphological features have a dependence on the
radio-optical position angle offset and on whether the source is a major- or
minor-axis source. The evidence indicates an anisotropic galaxy environment,
related to the ellipticity of the host galaxy, that causes the source linear
size evolution, strength of backflow in the radio lobes, off-axis lobe
distortions and the formation of wings and X-shaped radio sources to depend on
the radio-optical position angle offset. We identify a class of X-shaped radio
sources, which are either edge-darkened or lacking hotspots, and appear to have
inner doubles suggesting a restarting of activity. We suggest a common
formation mechanism, requiring backflows, for these apparently FR-I X-shaped
radio sources as well as the edge-brightened X-shaped sources.

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The categories of this paper are: supr-con
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The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
1
The categories of this paper are: cs
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
31
The categories of this paper are: ao-sci
19
The categories of this paper are: eess
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The categories of this paper are: patt-sol
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The categories of this paper are: nucl-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: comp-gas