XMM-Newton observation of an unusual iron line in the quasar Markarian 205

XMM-Newton observations of the low luminosity, radio-quiet quasar Markarian 305 have revealed a unique iron K emission line profile. In marked contras t to the broad and redshifted iron K line commonly seen in ASCA observation s of Seyfert 1 galaxies, we find that a substantial amount of the line flux ill Mrk 205 occurs above the neutral line energy of 6.4 keV. Furthermore, we find that the iron line emission has tyro distinct components, a narrow, unresolved neutral line at 6.4 keV and a broadened line centred at 6.7 keV . We suggest that the most likely origin of the 6.7 keV line is from X-ray reflection off the surface of a highly ionised accretion disk, whilst the 6 .4 keV component may arise from neutral matter distant from the black hole, quite possibly in the putative molecular torus. Overall this observation u nderlines the potential of XMM-Newton for using the iron It line as a diagn ostic of matter in the innermost regions of AGN.