Faint galaxies and the X-ray background
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.
Cite
@article{arxiv.astro-ph/9711150,
title = {Faint galaxies and the X-ray background},
author = {O. Almaini and T. Shanks and B. J. Boyle and I. Georgantopoulos and R. E. Griffiths and G. C. Stewart and K. F. Gunn and A. J. Blair},
journal= {arXiv preprint arXiv:astro-ph/9711150},
year = {2015}
}
Comments
Proceedings of the X-ray Surveys Workshop. To appear in Astron Nachr., 4 pages, 7 encapsulated figures, uses xsurv_article macro (included). Revised version with correct figure annotation, plus other minor changes. Also available from http://www.ast.cam.ac.uk/~omar/astro.html