Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The host galaxy of the z=2.4 radio-loud AGN MRC 0406-244 as seen by HST   We present multicolour Hubble Space Telescope images of the powerful z=2.4
radio galaxy MRC 0406-244 and model its complex morphology with several
components including a host galaxy, a point source, and extended nebular and
continuum emission. We suggest that the main progenitor of this radio galaxy
was a normal, albeit massive (M ~10^{11} solar masses), star-forming galaxy.
The optical stellar disc of the host galaxy is smooth and well described by a
S\'ersic profile, which argues against a recent major merger, however there is
also a point-source component which may be the remnant of a minor merger. The
half-light radius of the optical disc is constrained to lie in the range 3.5 to
8.2kpc, which is of similar size to coeval star forming galaxies.
  Biconical shells of nebular emission and UV-bright continuum extend out from
the host galaxy along the radio jet axis, which is also the minor axis of the
host galaxy. The origin of the continuum emission is uncertain, but it is most
likely to be young stars or dust-scattered light from the AGN, and it is
possible that stars are forming from this material at a rate of
200^{+1420}_{-110} solar masses per year.

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The categories of this paper are: q-bio
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The categories of this paper are: econ
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
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The categories of this paper are: q-alg
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The categories of this paper are: nucl-ex
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The categories of this paper are: gr-qc
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The categories of this paper are: cs
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The categories of this paper are: mtrl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-th
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The categories of this paper are: patt-sol
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The categories of this paper are: chem-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-ex