Gas, Iron, and Gravitational Mass in Galaxy Clusters: The General Lack of Cluster Evolution at z < 1.0

We have analyzed the ASCA data of 29 nearby clusters of galaxies systematically, and obtained temper­ atures, iron abundances, and X-ray luminosities of their intracluster medium (ICM). We also estimated the ICM mass using the (3 model, and then evaluated the iron mass contained in the ICM and derived the total gravitating mass. This gives the largest and most homogeneous information about the ICM derived only by ASCA data. We compared these values with those of distant clusters whose temperatures, abundances, and luminosities were also measured with ASCA, and have found no clear evidence of evolution for the clusters at z < 1.0. Only the most distant cluster at z = 1.0, AX J2019.3+1127, has an anomalously high iron abundance, but its iron mass in the ICM may be among normal values for the other clusters, because the ICM mass may be smaller than the other clusters. This may suggest a hint of evolution of clusters at z ~ 1.0.