Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A search for the hidden population of AM CVn binaries in the Sloan
  Digital Sky Survey   We present the latest results from a spectroscopic survey designed to uncover
the hidden population of AM Canum Venaticorum (AM CVn) binaries in the
photometric database of the Sloan Digital Sky Survey (SDSS). We selected ~2000
candidates based on their photometric colours, a relatively small sample which
is expected to contain the majority of all AM CVn binaries in the SDSS
(expected to be ~50).
  We present two new candidate AM CVn binaries discovered using this strategy:
SDSS J104325.08+563258.1 and SDSS J173047.59+554518.5. We also present spectra
of 29 new cataclysmic variables, 23 DQ white dwarfs and 21 DZ white dwarfs
discovered in this survey.
  The survey is now approximately 70 per cent complete, and the discovery of
seven new AM CVn binaries indicates a lower space density than previously
predicted. From the essentially complete g <= 19 sample, we derive an observed
space density of (5 +/- 3) x10^-7 pc^-3; this is lower than previous estimates
by a factor of 3.
  The sample has been cross-matched with the GALEX All-Sky Imaging Survey
database, and with Data Release 9 of the UKIRT (United Kingdom Infrared
Telescope) Infrared Deep Sky Survey (UKIDSS). The addition of UV photometry
allows new colour cuts to be applied, reducing the size of our sample to ~1100
objects. Optimising our followup should allow us to uncover the remaining AM
CVn binaries present in the SDSS, providing the larger homogeneous sample
required to more reliably estimate their space density.

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The categories of this paper are: math
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The categories of this paper are: hep-ex
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The categories of this paper are: q-bio
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The categories of this paper are: stat
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The categories of this paper are: math-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: supr-con
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The categories of this paper are: nucl-ex
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The categories of this paper are: adap-org
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The categories of this paper are: quant-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-ph
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The categories of this paper are: cs
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The categories of this paper are: gr-qc
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The categories of this paper are: econ