An X-ray Baldwin effect for the narrow FeK lines observed in active galactic nuclei

作者：Page KL^*; O'Brien PT; Reeves JN; Turner MJL

来源：Monthly Notices of the Royal Astronomical Society, 2004, 347(1): 316-322.

DOI：10.1111/j.1365-2966.2004.07203.x

• galaxies : active
• quasars : emission lines
• X-rays : galaxies

The majority of active galactic nuclei (AGN) observed by XMM-Newton reveal narrow Fe Kalpha lines at similar to6.4 keV, due to emission from cold (neutral) material. There is an X-ray Baldwin effect in type I AGN, in that the equivalent width (EW) of the line decreases with increasing luminosity, with weighted linear regression giving EW proportional to L-0.17+/-0.08 (Spearman Rank probability of > 99.9 per cent). 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 the covering factor of the material forming the fluorescence line.

• 出版日期2004-1-1