Statistical properties of metal abundances of the intracluster medium in the central region of clusters

We measured metal abundances of the intracluster medium in the central regi ons of 34 nearby clusters of galaxies, using ASCA data. Clusters that have a sharp X-ray emission centred on a cD galaxy are commonly found to exhibit a central increment in the Fe abundance, which is more pronounced in lower temperature clusters; +(0.1-0.2) solar at kT > 5 keV, compared with +(0.2- 0.3) solar at 1.5 < kT < 4 keV. These central excess metals are thought to be ejected from cD galaxies. Several low-temperature cD type clusters also show significant Si abundance increase by +(0.1-0.2) solar at the central r egion. Compared with the Si-rich. abundances observed in the outer regions of rich clusters, the Si to Fe abundance ratio of central excess metals ten ds to be near the solar ratio, implying that type Ia products from cD galax ies are dominant for the central excess metals. On the other hand, some oth er clusters do not show the central Fe abundance increase. As these cluster s tend to contain two or three central giant galaxies, it is suggested that galaxy interactions have removed the central abundance increase.