Ni abundance in the core of the Perseus Cluster: an answer to the significance of resonant scattering

Using an XMM-Newton observation of the Perseus cluster we show that the excess in the flux of the 7-8 keV line complex previously detected by ASCA and BeppoSAX is due to an overabundance of Nickel rather than to an anomalously high Fe Heβ/Fe Heα ratio. This observational fact leads to the main result that resonant scattering, which was assumed to be responsible for the supposed anomalous Fe Heβ/Fe Heα ratio, is no longer required. The absence of resonant scattering points towards the presence of significant gas motions (either turbulent or laminar) in the core of the Perseus cluster. Subject headings: X-rays: galaxies — Galaxies: clusters: individual: Perseus Abell 426 — Galaxies: abundances — intergalactic medium — scattering Università di Milano Bicocca, Dip. di Fisica, P.za della Scienza 3 I-20133 Milano, Italy