Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Molecular Gas in the Powerful Radio Nucleus of the Ultraluminous
  Infrared Galaxy PKS 1345+12   Millimeter CO(1-0) interferometry and high resolution, Hubble Space Telescope
(HST) 1.1, 1.6, and 2.2 micron imaging of the radio compact galaxy PKS 1345+12
are presented. With an infrared luminosity of 2x10^{12} L_sun, PKS 1345+12 is a
prime candidate for studying the link between the ultraluminous infrared galaxy
phenomenon and radio galaxies. These new observations probe the molecular gas
distribution and obscured nuclear regions of PKS 1345+12 and provide
morphological support for the idea that the radio activity in powerful radio
galaxies is triggered by the merger of gas rich galaxies. Two nuclei separated
by 2" (4.0 kpc) are observed in the near-infrared; the extended southeastern
nucleus has colors consistent with reddened starlight, and the compact
northwestern nucleus has extremely red colors indicative of an optical quasar
with a warm dust component. Further, the molecular gas, 3mm continuum, and
radio emission are coincident with the redder nucleus, confirming that the
northwestern nucleus is the site of the AGN and that the molecular gas is the
likely fuel source.

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The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
28
The categories of this paper are: alg-geom
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The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
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The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
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The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
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The categories of this paper are: physics
16
The categories of this paper are: stat