ICM masses in nearby and distant clusters of galaxies

Abstract

We compile X-ray data of clusters of galaxies at a wide range of redshift $z=0.0\sim1.0$ and compare X-ray luminosities, gas masses, iron abundances and iron masses of nearby clusters and those of distant clusters as a function of plasma temperature. All the date presented in this paper have been obtained only with \ASCA and/or \ROSAT. No evidence for a change in the \KT -\LX\ relationship or \KT - iron abundance at $z<0.6$ is found. No significant change in \KT -\LX relationship at $z>0.6$ is seen, either. However, the gas masses of very distant clusters at $z\sim0.8-1.0$ and some clusters around $z\sim0.6$ are significantly lower than those of nearby clusters, which indicates a hint of evolution. The iron masses of the two very distant clusters at $z\sim0.8-1.0$ are significantly different from each other, which suggests that the epoch of the metal injection into ICM is different from cluster to cluster.