Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Hubble Space Telescope Catalog of 449 Galaxies Seen Through the Disk
  of M31   From inspection of 30 Hubble Space Telescope ACS images of M31, we provide a
catalog of 449 galaxies seen through the spiral disk. Measurements of the
positions of the galaxies, their integrated magnitudes in two colors and their
sizes, determined from isophotometry, are included in the catalog. We discuss
the many difficulties of interpreting these data in terms of the effects of
intervening extinction by dust in the disk

20
The categories of this paper are: acc-phys
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The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
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The categories of this paper are: q-alg
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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: bayes-an
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
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The categories of this paper are: nlin
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The categories of this paper are: stat
10
The categories of this paper are: q-bio
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The categories of this paper are: q-fin
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The categories of this paper are: econ
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The categories of this paper are: hep-lat
2
The categories of this paper are: math