XMM-Newton unveils the complex iron Kα region of Mrk 279

We present the results of a ∼160 ks-long XMM-Newton observation of the Seyfert 1 galaxy Mrk 279. The spectrum shows evidence of both broad and narrow emission features. The FeKα line may be equally well explained by a single broad Gaussian (FWHM ∼ 10 000 km s−1) or by two components: an unresolved core plus a very broad profile (FWHM ∼ 14 000 km s−1). For the first time we quantified, via the “locally optimally emitting cloud” model, the contribution of the broad line region (BLR) to the absolute luminosity of the broad component of the FeKα at 6.4 keV. We find that the contribution of the BLR is only ∼3%. In the two-line component scenario, we also evaluated the contribution of the highly ionized gas component, which produces the Fe xxvi line in the iron K region. This contribution to the narrow core of the FeKα line is marginal