Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measurements of streaming motions of the Galactic bar with Red Clump
  Giants   We report a measurement of the streaming motion of the stars in the Galactic
bar with the Red Clump Giants (RCGs) using the data of the Optical
Gravitational Lensing Experiment II (OGLE-II). We measure the proper motion of
46,961 stars and divide RCGs into bright and faint sub-samples which on average
will be closer to the near and far side of the bar, respectively. We find that
the far-side RCGs (4,979 stars) have a proper motion of \Delta <\mu> ~ 1.5 +-
0.11 mas yr^{-1} toward the negative l relative to the near-side RCGs (3,610
stars). This result can be explained by stars in the bar rotating around the
Galactic center in the same direction as the Sun with v_b ~ 100 km s^{-1}. In
the Disc Star (DS) and Red Giant (RG) samples, we do not find significant
difference between bright and faint sub-samples. For those samples \Delta <\mu>
\~ 0.3 +- 0.14 mas yr^{-1} and ~ 0.03 +- 0.14 mas yr^{-1}, respectively. It is
likely that the average proper motion of RG stars is the same as that of the
Galactic center. The proper motion of DSs with respect to RGs is ~ 3.3 mas
yr^{-1} toward positive l. This value is consistent with the expectations for a
flat rotation curve and Solar motion with respect to local standard of rest.
RGs have proper motion approzimately equal to the average of bright and faint
RCGs, which implies that they are on average near the center of the bar. This
pilot project demonstrates that OGLE-II data may be used to study streaming
motions of stars in the Galactic bar. We intend to extend this work to all 49
OGLE-II fields in the Galactic bulge region.

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The categories of this paper are: quant-ph
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The categories of this paper are: q-alg
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The categories of this paper are: acc-phys
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The categories of this paper are: alg-geom
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: adap-org
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The categories of this paper are: econ
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The categories of this paper are: physics
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The categories of this paper are: eess
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The categories of this paper are: mtrl-th
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The categories of this paper are: funct-an
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The categories of this paper are: comp-gas
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The categories of this paper are: q-bio
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The categories of this paper are: hep-lat