On the X-ray Baldwin effect for narrow Fe Kalpha emission line

Abstract

Most Active Galactic Nuclei (AGN) exhibit a narrow Fe Kalpha line at ~ 6.4 keV in the X-ray spectra, due to the fluorescent emission from cold material far from the inner accretion disk. Using XMM-Newton observations, Page et al. found that the equivalent width (EW) of the narrow Fe Kalpha line decreases with increasing luminosity (EW ~ L^-0.17pm0.08), suggesting a decrease in the covering factor of the material emitting the line (presumably the torus). By combining the archival Chandra HETG observations of 34 type 1 AGNs with XMM observations in literature, we build a much large sample with 101 AGNs. We find a similar X-ray Baldwin effect in the sample (EW ~ L^-0.2015pm0.0426), however, we note that the anti-correlation is dominated by the radio loud AGN in the sample, whose X-ray spectra might be contaminated by the relativistic jet. Excluding the radio loud AGN, we find a much weaker anti-correlation (EW ~ L^-0.1019pm0.0524). We present Monte-Carlo simulations showing that such a weak anti-correlation can be attributed to the relative short time scale variations of the X-ray continuum.

21 pages, including 3 tables and 7 figures, ApJ 2006, v644 in press

References in corpus (13)

• Cosmological Evolution of the Hard X-ray AGN Luminosity Function and the Origin of the Hard X-ray Background
• Fluorescent iron lines as a probe of astrophysical black hole systems
• The luminosity dependence of the Type 1 AGN fraction
• The obscuration by dust of most of the growth of supermassive black holes
• The Changing AGN Population
• On the dependence of the iron K-line profiles with luminosity in Active Galactic Nuclei
• The Cores of the Fe K Lines in Seyfert I Galaxies Observed by the Chandra High Energy Grating
• The Swift/BAT High Latitude Survey: First Results
• An X-ray Baldwin effect for the narrow Fe K-alpha lines observed in Active Galactic Nuclei
• An Expanded RXTE Survey of X-ray Variability in Seyfert 1 Galaxies
• Narrow Iron K$\alpha$ Lines in Active Galactic Nuclei: Evolving Populations?
• The XMM-Newton view of PG quasars: II. Properties of the Fe K-alpha line
• XMM-Newton observations of high-luminosity radio-quiet QSOs

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