Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The pattern speeds of NGC 6946   We study the kinematics of the barred spiral galaxy NGC 6946 by investigating
the velocity field from H-alpha Fabry-Perot observations, determined the
pattern speed of the bar by using the Tremaine-Weinberg method, and find a main
pattern speed of 21.7 (+4.0,-0.8) km/s/kpc. Our data clearly suggest the
presence of an additional pattern with a pattern speed more than twice that of
the large pattern in this galaxy. We use the epicycle approximation to deduce
the location of the resonance radii and subsequently determine the pattern
speed between the radii, and find that inside the inner Inner Lindblad
Resonance radius, a bar-like system has evolved.

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The categories of this paper are: hep-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: bayes-an
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The categories of this paper are: adap-org
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-bio
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The categories of this paper are: quant-ph
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The categories of this paper are: nlin
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-th
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The categories of this paper are: funct-an
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The categories of this paper are: eess
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The categories of this paper are: hep-ex
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The categories of this paper are: econ
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The categories of this paper are: gr-qc