Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Pristine survey II: a sample of bright stars observed with FEROS   Extremely metal-poor (EMP) stars are old objects formed in the first Gyr of
the Universe. They are rare and, to select them, the most successful strategy
has been to build on large and low-resolution spectroscopic surveys. The
combination of narrow- and broad band photometry provides a powerful and
cheaper alternative to select metal-poor stars. The on-going Pristine Survey is
adopting this strategy, conducting photometry with the CFHT MegaCam wide field
imager and a narrow-band filter centred at 395.2 nm on the CaII-H and -K lines.
In this paper we present the results of the spectroscopic follow-up conducted
on a sample of 26 stars at the bright end of the magnitude range of the Survey
(g<=15), using FEROS at the MPG/ESO 2.2 m telescope. From our chemical
investigation on the sample, we conclude that this magnitude range is too
bright to use the SDSS gri bands, which are typically saturated. Instead the
Pristine photometry can be usefully combined with the APASS gri photometry to
provide reliable metallicity estimates.

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The categories of this paper are: math
33
The categories of this paper are: plasm-ph
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The categories of this paper are: econ
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
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The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-ph
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The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: solv-int
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The categories of this paper are: supr-con
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The categories of this paper are: comp-gas
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The categories of this paper are: chao-dyn