The strength and width of Fe Kalpha lines in Seyferts and their   correlations with the X-ray slope
  We study properties of Fe K lines of a large sample of Seyfert 1s observed by ASCA. Fits with power laws and Gaussian lines yield the average linewidth and equivalent width of 0.22+-0.03 keV and 0.13+-0.01 keV, respectively. Thus, the typical lines are weak and narrow. We then obtain the average line profile of all our spectra, and find it to consist of a narrow core and blue and red wings, with the red wing being much weaker than that of, e.g., MCG-6-30-15. We obtain three average spectra of Seyferts grouped according to the hardness, and find the equivalent width of the core (originating in a remote medium) to be about 50 eV in all three cases. The wings are well fitted by a broad line from a disc with strong relativistic effects. Its equivalent width correlates with the slope, increasing from ~70 eV for the hardest spectrum to ~120 eV for the softest one. The inner disc radius decreases correspondingly from ~40 to ~10 gravitational radii, and the fitted disc inclination is ~45 degrees. The obtained correlation between the slope and the strength of the broad Fe K line is found to be consistent with the previously found correlation of the slope and Compton reflection. 
Piotr Lubinski (1 and 2), Andrzej Zdziarski (1) ((1) N. Copernicus   Astronomical Center, Warsaw, Poland, (2) Heavy Ion Labo...