Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Interstellar medium, young stars, and astrometric binaries in Galactic
  archaeology spectroscopic surveys   Current ongoing stellar spectroscopic surveys (RAVE, GALAH, Gaia-ESO, LAMOST,
APOGEE, Gaia) are mostly devoted to studying Galactic archaeology and structure
of the Galaxy. But they allow for important auxiliary science: (i) Galactic
interstellar medium can be studied in four dimensions (position in space +
radial velocity) through weak but numerous diffuse insterstellar bands and
atomic absorptions seen in spectra of background stars, (ii) emission spectra
which are quite frequent even in field stars can serve as a good indicator of
their youth, pointing e.g. to stars recently ejected from young stellar
environments, (iii) astrometric solution of the photocenter of a binary to be
obtained by Gaia can yield accurate masses when joined by spectroscopic
information obtained serendipitously during a survey.
  These points are illustrated by first results from the first three surveys
mentioned above. These hint at the near future: spectroscopic studies of the
dynamics of the interstellar medium can identify and quantify Galactic
fountains which may sustain star formation in the disk by entraining fresh gas
from the halo; RAVE already provided a list of ~14,000 field stars with
chromosperic emission in Ca II lines, to be supplemented by many more
observations by Gaia in the same band, and by GALAH and Gaia-ESO observations
of Balmer lines; several millions of astrometric binaries with periods up to a
few years which are being observed by Gaia can yield accurate masses when
supplemented with measurements from only a few high-quality ground based
spectra.

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The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
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The categories of this paper are: plasm-ph
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The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
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The categories of this paper are: hep-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: acc-phys
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The categories of this paper are: math
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
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The categories of this paper are: q-fin
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The categories of this paper are: eess
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The categories of this paper are: chem-ph
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The categories of this paper are: q-alg