Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Emission line galaxies behind the planetary nebula IC 5148: Potential
  for a serendipity survey with archival data   During the start of a survey program using FORS2 long slit spectroscopy on
planetary nebulae (PN) and their haloes, we serendipitously discovered six
background emission line galaxies (ELG) with redshifts of z = 0.2057, 0.3137,
0.37281, 0.4939, 0.7424 and 0.8668. Thus they clearly do not belong to a common
cluster structure. We derived the major physical properties of the targets.
Since the used long slit covers a sky area of only 570 arcsec^2, we discuss
further potential of serendipitous discoveries in archival data, beside the
deep systematic work of the ongoing and upcoming big surveys. We conclude that
archival data provide a decent potential for extending the overall data on ELGs
without any selection bias.

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The categories of this paper are: solv-int
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The categories of this paper are: nlin
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: hep-th
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The categories of this paper are: stat
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The categories of this paper are: econ
37
The categories of this paper are: supr-con
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The categories of this paper are: patt-sol
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The categories of this paper are: nucl-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: physics
1
The categories of this paper are: cs
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The categories of this paper are: chao-dyn
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The categories of this paper are: quant-ph
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The categories of this paper are: atom-ph