Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Kinematics of the outer pseudorings and the spiral structure of the
  Galaxy   The kinematics of the outer rings and pseudorings is determined by two
processes: the resonance tuning and the gas outflow. The resonance kinematics
is clearly observed in the pure rings, while the kinematics of the gas outflow
is manifested itself in the pseudorings. The direction of systematical motions
in the pure rings depends on the position angle of a point with respect to the
bar major axis and on the class of the outer ring. The direction of the radial
and azimuthal components of the residual velocities of young stars in the
Perseus, Carina, and Sagittarius regions can be explained by the presence of
the outer pseudoring of class R1R2' in the Galaxy. We present models, which
reproduce the directions and values of the residual velocities of
OB-associations in the Perseus and Sagittarius regions, and also model
reproducing the directions of the residual velocities in the Perseus,
Sagittarius, and Carina regions. The kinematics of the Sagittarius region
accurately defines the solar position angle with respect to the bar elongation,
theta_b=45 (+/-5) deg.

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The categories of this paper are: hep-ex
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The categories of this paper are: nucl-th
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The categories of this paper are: adap-org
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The categories of this paper are: math
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The categories of this paper are: econ
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
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The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: q-bio
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The categories of this paper are: patt-sol
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The categories of this paper are: chao-dyn