The strength and width of FeKα 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 similar to 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 similar to 70 eV for the hardest spectrum to similar to 120eV for the softest one. The inner disc radius decreases correspondingly from similar to 40 to similar to 10 gravitational radii, and the fitted disc inclination is similar to 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.