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Paper: Charting the Obscured AGN Population in the Deepest XMM-Newton Surveys
Volume: 380, At the Edge of the Universe: Latest Results from the Deepest Astronomical Surveys
Page: 145
Authors: Dwelly, T.; Page, M.; McHardy, I.; Moss, D.; Seymour, N.; Loaring, N.
Abstract: The best way to constrain Active Galactic Nuclei (AGN) absorption properties over a wide range of luminosity and redshift is by examining the extragalactic X-ray population. In the very deep XMM-Newton observations of the Chandra Deep Field South (CDFS), there are >300 X-ray detections, 84% of which have redshift estimates, and nearly all of which are AGN. This AGN sample spans more than four decades in intrinsic luminosity. We determine the absorbing column densities and intrinsic luminosities of these AGN using a Monte-Carlo method, which exploits the wide bandpass (0.210 keV), and high throughput of XMM-Newton. A detailed simulation scheme is then used to compare the X-ray properties of the sources with the predictions of a number of theoretical AGN population models. We find that the observed AGN absorption distribution exhibits no strong dependence on either luminosity or redshift. The best matching population model contains AGN having a wide range of absorbing columns, with the heavily absorbed AGN outnumbering the unabsorbed objects by 3:1. In particular, our results are consistent with there being a large population of heavily absorbed (NH > 1022 cm−2), intrinsically luminous (LX > 1044 erg s−1) AGN.
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