Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Infrared 3-4 Micron Spectroscopy of Infrared Luminous Galaxies with
  Possible Signatures of Obscured Active Galactic Nuclei   We present the results of infrared 2.8-4.1 micron (L-band) spectroscopy of
nearby infrared luminous galaxies with possible signatures of dust-obscured
active galactic nuclei (AGNs) in data at other wavelengths. The samples are
chosen to include sources with a radio excess relative to far-infrared
emission, strong absorption features in mid-infrared 5-11.5 micron spectra,
unusually weak [CII] 158 micron emission relative to the far-infrared
continuum, and radio galaxies classified optically as narrow-line objects. Our
aim is to investigate whether the signatures of possible obscured AGNs can be
detected in our L-band spectra, based on the strengths of emission and
absorption features. Six of nine observed sources clearly show 3.3 micron
polycyclic aromatic hydrocarbon (PAH) emission features, a good starburst
indicator. An absorption feature at 3.1 micron due to ice-covered dust is
detected in IRAS 04154+1755 and IRAS 17208-0014. The signature of a bare
carbonaceous dust absorption feature at 3.4 micron is seen in NGC 1377. Our
L-band spectra reveal strong signatures of obscured AGNs in all three optical
Seyfert 2 galaxies (IRAS 04154+1755, Cygnus A, and 3C 234), and two galaxies
classified optically as non-Seyferts (NGC 828 and NGC 1377). Among the
remaining optical non-Seyferts, IRAS 17208-0014 might also show a buried AGN
signature, whereas no explicit AGN evidence is seen in the L-band spectra of
the mid-infrared absorption-feature source IRAS 15250+3609, and two weak [CII]
emitters IC 860 and CGCG 1510.8+0725.

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The categories of this paper are: hep-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: cs
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The categories of this paper are: quant-ph
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
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The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
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The categories of this paper are: nlin
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The categories of this paper are: math-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: physics