Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Photometric and Spectroscopic Search for White Dwarfs in the Open
  Clusters NGC 6633 and NGC 7063   We present photometric and spectroscopic studies of the white dwarf (WD)
populations in the intermediate-age open clusters NGC 6633 and NGC 7063 as part
of the ongoing Lick-Arizona White Dwarf Survey (LAWDS). Using wide-field CCD
imaging, we locate 41 candidate WDs in the two cluster fields: 32 in NGC 6633,
and 9 in NGC 7063. Spectroscopic observations confirm 13 of these candidates to
be bona-fide WDs. We describe in detail our Balmer line fitting technique for
deriving effective temperatures and surface gravities from optical DA WD
spectra and apply the technique to the 11 DA WDs in the sample. Of these, only
two DA WDs are at the cluster distance moduli, one in each cluster. Two more
DAs lie 0.75 mag foreground to NGC 6633, raising the possibility that these are
double degenerate systems in the cluster. If nearly equal-mass binaries, both
of these systems likely have combined masses above the Chandrasekhar limit. One
DB WD is found to be consistent with membership in NGC 6633, which would make
this the third confirmed He-atmosphere WD in an open cluster, though further
data are needed to confirm cluster membership. The WD consistent with
membership in the cluster NGC 7063 has a low mass (~0.4 Mo), suggesting it may
be a He-core WD resulting from close binary evolution. Three of the eleven
hydrogen-atmosphere WDs in this study are observed to have Ca II absorption;
the number of DAZs in this study is consistent with previous observations that
~25% of field WDs are DAZs.

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The categories of this paper are: cmp-lg
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The categories of this paper are: math-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: chem-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: mtrl-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: gr-qc
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The categories of this paper are: nlin
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The categories of this paper are: supr-con
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The categories of this paper are: eess
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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: cond-mat
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The categories of this paper are: plasm-ph