Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optical and Near-Infrared Spectroscopy of a High-Redshift, Hard X-ray
  Emitting Spiral Galaxy   We present optical and near-infrared Keck spectroscopy of CXOHDFN
J123635.6+621424 (hereafter HDFX28), a hard X-ray source at a redshift of z =
2.011 in the flanking fields of the Hubble Deep Field-North (HDF-N). HDFX28 is
a red source (R - K_s = 4.74) with extended steep-spectrum (alpha > 0.87)
microjansky radio emission and significant emission (441 microJy) at 15
microns. Accordingly, initial investigations prompted the interpretation that
HDFX28 is powered by star formation. Subsequent Chandra imaging, however,
revealed hard (Gamma = 0.30) X-ray emission indicative of absorbed AGN
activity, implying that HDFX28 is an obscured, Type II AGN. The optical and
near-infrared spectra presented herein corroborate this result; the
near-infrared emission lines cannot be powered by star formation alone, and the
optical emission lines indicate a buried AGN. HDFX28 is identified with a
face-on, moderately late-type spiral galaxy. Multi-wavelength morphological
studies of the HDF-N have heretofore revealed no galaxies with any kind of
recognizable spiral structure beyond z > 2. We present a quantitative analysis
of the morphology of HDFX28, and we find the measures of central concentration
and asymmetry to be indeed consistent with those expected for a rare
high-redshift spiral galaxy.

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The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-lat
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The categories of this paper are: q-bio
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The categories of this paper are: chem-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: acc-phys
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The categories of this paper are: cs
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The categories of this paper are: hep-th
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The categories of this paper are: dg-ga
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The categories of this paper are: eess