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 1.75, much softer than the = 1.4 of the total background spectrum. The unresolved background component has the spectral signature of highly obscured active galactic nuclei.
No takes yet. Share an insight, caveat, or question.
Worsley et al. (2004) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: