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arXiv · astro-ph/9711150

Faint galaxies and the X-ray background

O. Almaini·T. Shanks·B. J. Boyle·I. Georgantopoulos·R. E. Griffiths·G. C. Stewart·K. F. Gunn·A. J. Blair
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Abstract

We summarise our recent work on the faint galaxy contribution to the cosmic X-ray background (XRB). At bright X-ray fluxes (in the ROSAT pass band), broad line QSOs dominate the X-ray source population, but at fainter fluxes there is evidence for a significant contribution from emission-line galaxies. Here we present statistical evidence that these galaxies can account for a large fraction of the XRB. We also demonstrate that these galaxies have significantly harder X-ray spectra than QSOs. Finally we present preliminary findings from infra-red spectroscopy on the nature of this X-ray emitting galaxy population. We conclude that a hybrid explanation consisting of obscured/Type 2 AGN surrounded by starburst activity can explain the properties of these galaxies and perhaps the origin of the entire XRB.

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O. Almaini, T. Shanks, B. J. Boyle, I. Georgantopoulos, R. E. Griffiths, G. C. Stewart, K. F. Gunn, A. J. Blair. 1997-11-14. Faint galaxies and the X-ray background. https://doi.org/10.1002/asna.2123190125

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