Description
Bright XMM-Newton data are combined with the Chandra Deep Field South observations to explore the behavior of the intrinsic AGN absorption, as a function of redshift and luminosity. The sample consists of 359 sources selected in the hard 2 - 8 keV band, spanning the flux range from 6 x 10<sup>-16</sup> - 3 x 10<sup>-13</sup> erg/cm<sup>2</sup>/s with a high rate of spectroscopic or photometric redshift completeness (100 and 85 percent for the Chandra and XMM-Newton data, respectively). The authors derive the column density values using X-ray spectral fits. They find that the fraction of obscured AGN falls with increasing luminosity in agreement with previous findings. The fraction of obscured AGN shows an apparent increase at high redshifts (z > 2). Simulations show that this effect can most probably be attributed to the fact that at high redshifts the column densities are overestimated. This table contains the subset of 153 brighter hard X-ray sources in the XMM-Newton/Sloan Digital Sky Survey (SDSS) sample which have 2-8 keV fluxes > 3 x 10<sup>-14</sup> erg cm<sup>-2</sup> s<sup>-1</sup>, excluding a number of sources with extended optical morphology and blue colors, as well as 4 sources with X-ray to optical fluxes < 0.1 which are fit better with stellar rather than QSO templates. Much more information on the SDSS is available at the project's web site at <a href="http://www.sdss.org/">http://www.sdss.org/</a>. This table was created by the HEASARC in July 2007 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/459/693">CDS Catalog J/A+A/459/693</a> file table2.dat. This is a service provided by NASA HEASARC .
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