Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Two types of shock in the hotspot of the giant quasar 4C74.26: a
  high-resolution comparison from Chandra, Gemini & MERLIN   New Chandra observations have resolved the structure of the X-ray luminous
southern hotspot in the giant radio quasar 4C74.26 into two distinct features.
The nearer one to the nucleus is an extremely luminous peak, extended some 5
kpc perpendicular to the orientation of the jet; 19 kpc projected further away
from the central nucleus than this is a fainter X-ray arc having similar
symmetry. This arc is co-spatial with near-IR and optical emission imaged with
Gemini, and radio emission imaged with MERLIN. The angular separation of the
double shock structure (itself ~19 kpc or 10 arcsec in size) from the active
nucleus which fuels them of ~550 kpc is a reminder of the challenge of
connecting "unidentified" hard X-ray or Fermi sources with their origins.

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The categories of this paper are: alg-geom
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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: math
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The categories of this paper are: chem-ph
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The categories of this paper are: q-fin
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The categories of this paper are: hep-th
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The categories of this paper are: nlin
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The categories of this paper are: hep-ph
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The categories of this paper are: adap-org
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The categories of this paper are: q-bio
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-ex
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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas