Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Molecular gas and dust in NGC4550: A galaxy with two counterrotating
  stellar disks   We report the detection of 1 10^7 M_sun of molecular gas in the central
region of the S0/E7 galaxy NGC4550, inferred from observations of CO(1-0)
emission. Dust is detected in HST WFPC2 images and found to be asymmetrically
distributed around the nucleus, only extending to a galactocentric distance of
7'' (600 pc). The shape of the CO emission profile is consistent with a
molecular gas distribution following the dust. The distribution of the dust and
gas in the center could be the result of an m=1 instability, which is the
fastest growing unstable mode in counterrotating stellar disks. On a global
scale the molecular gas in NGC4550 is stable against gravitational collapse but
nevertheless star formation appears to be ongoing with normal star formation
efficiency and gas consumption time scales. The stellar velocity dispersion in
NGC4550 resembles that of elliptical galaxies. It is therefore likely that a
hot X-ray emitting plasma limits the lifetime of the molecular gas, that must
arise from a recent (<1 Gyr) accretion event.

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The categories of this paper are: stat
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The categories of this paper are: funct-an
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The categories of this paper are: adap-org
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The categories of this paper are: hep-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: supr-con
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The categories of this paper are: chem-ph
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The categories of this paper are: physics
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The categories of this paper are: math-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-lat
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The categories of this paper are: eess
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The categories of this paper are: patt-sol
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The categories of this paper are: q-bio
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The categories of this paper are: gr-qc
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The categories of this paper are: solv-int