A Definitive Test for Evolution in the Metallicity of the Intracluster Medium

We propose deep observations of two massive galaxy clusters, at redshifts of1.84 and 1.03, to measure the metallicity of the ICM at very high redshifts.These data will definitively test the early enrichment scenario, in which mostof the metal enrichment of the intergalactic medium occurs before clusters form,during the period of maximal star formation and black hole activity, more than10 Gyr ago. This scenario is supported by highprecision Suzaku measurements ofa homogeneous iron distribution in the nearby Perseus cluster, extending to thevirial radius. Our proposal will provide a direct and precise test of earlyenrichment, probing the distribution of iron in our z1.03 target and theoverall, coreexcised metallicity of the most luminous, distant cluster known. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]