The (un)resolved X-ray background in the Lockman Hole
Abstract
Most of the soft and a growing fraction of the harder X-ray background has been resolved into emission from point sources, yet the resolved fraction above 7 keV has only been poorly constrained. We use ~700 ks of XMM-Newton observations of the Lockman Hole and a photometric approach to estimate the total flux attributable to resolved sources in a number of different energy bands. We find the resolved fraction of the X-ray background to be ~90 per cent below 2 keV but it decreases rapidly at higher energies with the resolved fraction above ~7 keV being only ~50 per cent. The integrated X-ray spectrum from detected sources has a slope of Gamma~1.75, much softer than the Gamma=1.4 of the total background spectrum. The unresolved background component has the spectral signature of highly obscured AGN.
Cite
@article{arxiv.astro-ph/0404273,
title = {The (un)resolved X-ray background in the Lockman Hole},
author = {M. A. Worsley and A. C. Fabian and X. Barcons and S. Mateos and G. Hasinger and H. Brunner},
journal= {arXiv preprint arXiv:astro-ph/0404273},
year = {2009}
}
Comments
6 pages, 6 figures, MNRAS Letters, in press, changed to reflect accepted version