An X-ray Baldwin effect for the narrow Fe K-alpha lines observed in Active Galactic Nuclei
Astrophysics
2009-11-10 v1
Abstract
The majority of Active Galactic Nuclei (AGN) observed by XMM-Newton reveal narrow Fe K-alpha lines at ~ 6.4 keV, due to emission from cold (neutral) material. There is an X-ray Baldwin effect in Type I AGN, in that the equivalent width of the line decreases with increasing luminosity, with weighted linear regression giving EW ~ L^{-0.17+/-0.08} (Spearman Rank probability of > 99.9%). With current instrumental capabilities it is not possible to determine the precise origin for the narrow line, with both the Broad Line Region and putative molecular torus being possibilities. A possible explanation for the X-ray Baldwin effect is a decrease in covering factor of the material forming the fluorescence line.
Keywords
Cite
@article{arxiv.astro-ph/0309394,
title = {An X-ray Baldwin effect for the narrow Fe K-alpha lines observed in Active Galactic Nuclei},
author = {K. L. Page and P. T. O'Brien and J. N. Reeves and M. J. L. Turner},
journal= {arXiv preprint arXiv:astro-ph/0309394},
year = {2009}
}
Comments
8 pages, 6 figures, accepted by MNRAS