The unresolved hard X-ray background: the missing source population implied by the Chandra and XMM-Newton deep fields
Abstract
We extend our earlier work on X-ray source stacking in the deep XMM-Newton observation of the Lockman Hole, to the 2 Ms Chandra Deep Field North and the 1 Ms Chandra Deep Field South. The XMM-Newton work showed the resolved fraction of the X-ray background to be ~80-100 per cent at <2 keV but this decreased to only ~50 per cent above ~8 keV. The CDF-N and CDF-S probe deeper, and are able to fill-in some of the missing fraction in the 4-6 keV range, but the resolved fraction in the 6-8 keV band remains only ~60 per cent, confirming the trend seen with XMM-Newton. The missing X-ray background component has a spectral shape that is consistent with a population of highly obscured AGN at redshifts \~0.5-1.5 and with absorption column densities of ~10^23 - 10^24 cm^-2.
Cite
@article{arxiv.astro-ph/0412266,
title = {The unresolved hard X-ray background: the missing source population implied by the Chandra and XMM-Newton deep fields},
author = {M. A. Worsley and A. C. Fabian and F. E. Bauer and D. M. Alexander and G. Hasinger and S. Mateos and H. Brunner and W. N. Brandt and D. P. Schneider},
journal= {arXiv preprint arXiv:astro-ph/0412266},
year = {2009}
}
Comments
7 pages, 4 figures, MNRAS accepted