The contribution of AGN to the X-ray background: the effect of iron features

The contribution of the iron emission line, commonly detected in the X-ray spectra of Seyfert (Sey) galaxies, to the cosmic X-ray background (XRB) spe ctrum is evaluated in the framework of the XRB synthesis models based on AG N unification schemes. To derive the mean line properties, we have carried out a search in the literature covering a sample of about 70 AGN. When adop ting line parameters in agreement with the observations, it turns out that the maximum contribution of the iron line to the XRB is less than 7% at a f ew keV. This is still below the present uncertainties in the XRB spectrum m easurements. (C) 1999 Elsevier Science B. V. All rights reserved.