Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Limit on the Number of Isolated Neutron Stars Detected in the ROSAT
  Bright Source Catalog   The challenge in searching for non-radio-pulsing isolated neutron stars
(INSs) is in excluding association with objects in the very large error boxes
(~13", 1 sigma radius) typical of sources from the largest X-ray all-sky
survey, the ROSAT All-Sky-Survey/Bright Source Catalog (RASS/BSC). We search
for candidate INSs using statistical analysis of optical (USNO-A2), infrared
(IRAS), and radio (NVSS) sources near the ROSAT X-ray localization, and show
that this selection would find 20% of the INSs in the RASS/BSC. This selection
finds 32 candidates at declinations greater than -39 deg, among which are two
previously known INSs, seventeen sources which we show are not INSs, and
thirteen the classification of which are as yet undetermined. These results
require a limit of <67 INSs (90% confidence, full sky, assuming isotropy) in
the RASS/BSC. This limit modestly constrains a naive and optimistic model for
cooling NSs in the galaxy.

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The categories of this paper are: mtrl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: funct-an
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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: stat
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: math
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The categories of this paper are: hep-lat
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The categories of this paper are: adap-org
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The categories of this paper are: econ
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The categories of this paper are: physics
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The categories of this paper are: chao-dyn