Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A survey for low-mass stellar and substellar members of the Hyades open
  cluster   Unlike young open clusters (with ages <250 Myr), the Hyades cluster (age ~600
Myr) has a clear deficit of very low-mass stars (VLM) and brown dwarfs (BD).
Since this open cluster has a low stellar density and covers several tens of
square degrees on the sky, extended surveys are required to improve the
statistics of the VLM/BD objects in the cluster. We search for new VLM stars
and BD candidates in the Hyades to improve the present-day cluster mass
function down to substellar masses. An imaging survey of the Hyades with a
completeness limit of 21m.5 in the $R$ band and 20m.5 in the $I$ band was
carried out with the 2kx2k CCD Schmidt camera at the 2m Alfred Jensch Telescope
in Tautenburg. We performed a photometric selection of the cluster member
candidates by combining results of our survey with 2MASS JHKs photometry. We
present a photometric and proper motion survey covering 23.4 deg$^2$ in the
Hyades cluster core region. Using optical/IR colour-magnitude diagrams, we
identify 66 photometric cluster member candidates in the magnitude range
14m.7<I<20m.5. The proper motion measurements are based on several all-sky
surveys with an epoch difference of 60-70 years for the bright objects. The
proper motions allowed us to discriminate the cluster members from field
objects and resulted in 14 proper motion members of the Hyades. We rediscover
Hy 6 as a proper motion member and classify it as a substellar object candidate
(BD) based on the comparison of the observed colour-magnitude diagram with
theoretical model isochrones. With our results, the mass function of the Hyades
continues to be shallow below 0.15 $M_\odot$ indicating that the Hyades have
probably lost their lowest mass members by means of dynamical evolution. We
conclude that the Hyades core represents the `VLM/BD desert' and that most of
the substeller objects may have already left the volume of the cluster.

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The categories of this paper are: adap-org
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The categories of this paper are: math-ph
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The categories of this paper are: econ
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The categories of this paper are: quant-ph
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The categories of this paper are: q-alg
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-ex
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The categories of this paper are: bayes-an
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The categories of this paper are: dg-ga
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The categories of this paper are: acc-phys
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The categories of this paper are: cond-mat
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The categories of this paper are: cs