Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: XBootes: An X-Ray Survey of the NDWFS Bootes Field - Paper I Overview
  and Initial Results   We obtained a 5 ksec deep Chandra X-ray Observatory ACIS-I map of the 9.3
square degree Bootes field of the NOAO Deep Wide-Field Survey. Here we describe
the data acquisition and analysis strategies leading to a catalog of 4642
(3293) point sources with 2 or more (4 or more) counts, corresponding to a
limiting flux of roughly 4(8)x10^{-15} erg cm^{-2}s^{-1} in the 0.5-7 keV band.
These Chandra XBootes data are unique in that they consitute the widest
contiguous X-ray field yet observed to such a faint flux limit. Because of the
extraordinarily low background of the ACIS, we expect only 14% (0.7%) of the
sources to be spurious. We also detected 43 extended sources in this survey.
The distribution of the point sources among the 126 pointings (ACIS-I has a 16
x 16 arcminute field of view) is consistent with Poisson fluctuations about the
mean of 36.8 sources per pointing. While a smoothed image of the point source
distribution is clumpy, there is no statistically significant evidence of large
scale filamentary structure. We do find however, that for theta>1 arcminute,
the angular correlation function of these sources is consistent with previous
measurements, following a power law in angle with slope -0.7. In a 1.4 deg^{2}
sample of the survey, approximately 87% of the sources with 4 or more counts
have an optical counterpart to R ~26 mag. As part of a larger program of
optical spectroscopy of the NDWFS Bootes area, spectra have been obtained for
\~900 of the X-ray sources, most of which are QSOs or AGN.

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The categories of this paper are: eess
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The categories of this paper are: gr-qc
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The categories of this paper are: stat
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The categories of this paper are: ao-sci
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The categories of this paper are: plasm-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-th
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-lat
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The categories of this paper are: cond-mat
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The categories of this paper are: chem-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: funct-an
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The categories of this paper are: supr-con
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The categories of this paper are: atom-ph
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The categories of this paper are: nlin