Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Detection of the old stellar component of the major Galactic bar   We present near-IR colour--magnitude diagrams and star counts for a number of
regions along the Galactic plane. It is shown that along the l=27 b=0 line of
sight there is a feature at 5.7 +-0.7kpc with a density of stars at least a
factor two and probably more than a factor five times that of the disc at the
same position. This feature forms a distinct clump on an H vs. J-H diagram and
is seen at all longitudes from the bulge to about l=28, but at no longitude
greater than this. The distance to the feature at l=20 is about 0.5kpc further
than at l=27 and by l=10 it has merged with, or has become, the bulge. Given
that at l=27 and l=21 there is also a clustering of very young stars, the only
component that can reasonably explain what is seen is a bar with half length of
around 4kpc and a position angle of about 43+-7.

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The categories of this paper are: plasm-ph
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The categories of this paper are: cmp-lg
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc
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The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-lat
1
The categories of this paper are: cs
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The categories of this paper are: econ
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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int
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The categories of this paper are: q-alg
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The categories of this paper are: supr-con
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The categories of this paper are: ao-sci