Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Discovery of H alpha absorption in the unusual broad absorption line
  quasar SDSS J083942.11+380526.3   We discovered an H alpha absorption in a broad H alpha emission line of an
unusual broad absorption line quasar, SDSS J083942.11+380526.3 at z=2.318, by
near-infrared spectroscopy with the Cooled Infrared Spectrograph and Camera for
OHS (CISCO) on the Subaru telescope. The Presence of non-stellar H alpha
absorption is known only in the Seyfert galaxy NGC 4151 to date, thus our
discovery is the first case for quasars. The H alpha absorption line is
blueshifted by 520 km/s relative to the H alpha emission line, and its redshift
almost coincides with those of UV low-ionization metal absorption lines. The
width of the H alpha absorption (~ 340 km/s) is similar to those of the UV
low-ionization absorption lines. These facts suggest that the H alpha and the
low-ionization metal absorption lines are produced by the same low-ionization
gas which has a substantial amount of neutral gas. The column density of the
neutral hydrogen is estimated to be ~ 10^18 cm^-2 by assuming a gas temperature
of 10,000 K from the analysis of the curve of growth. The continuum spectrum is
reproduced by a reddened (E(B-V) ~ 0.15 mag for the SMC-like reddening law)
composite quasar spectrum. Furthermore, the UV spectrum of SDSS
J083942.11+380526.3 shows a remarkable similarity to that of NGC 4151 in its
low state, suggesting the physical condition of the absorber in SDSS
J083942.11+380526.3 is similar to that of NGC 4151 in the low state. As
proposed for NGC 4151, SDSS J083942.11+380526.3 may be also seen through the
close direction of the surface of the obscuring torus.

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The categories of this paper are: eess
3
The categories of this paper are: physics
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The categories of this paper are: hep-lat
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The categories of this paper are: chem-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: adap-org
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The categories of this paper are: supr-con
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The categories of this paper are: atom-ph
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The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
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The categories of this paper are: math
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The categories of this paper are: ao-sci
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-bio