XBootes: An X-ray survey of the NDWFS Bootes field. I. Overview and initial results

Stephen S. Murray, Almus Kenter, William R. Forman, Christine Jones, Paul J. Green, Christopher S. Kochanek, Alexey Vikhlinin, Daniel Fabricant, Giovani Fazio, Kate Brand, Michael J.I. Brown, Arjun Dey, Buell T. Jannuzi, Joan Najita, Brian Mcnamara, Joseph Shields, Marcia Rieke

Research output: Contribution to journalArticlepeer-review

133 Scopus citations


We obtained a 5 ks deep Chandra X-ray Observatory ACIS-I map of the 9.3 deg 2 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) × 10 -15 ergs cm -2 s -1 in the 0.5-7 keV band. These Chandra XBootes data are unique in that they constitute 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′ × 16′ 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 θ > 1′, 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 quasars or active galactic nuclei.

Original languageEnglish (US)
Pages (from-to)1-8
Number of pages8
JournalAstrophysical Journal, Supplement Series
Issue number1
StatePublished - Nov 2005


  • Galaxies: active
  • Surveys
  • X - Rays: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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