New Results with the XIS Onboard Suzaku

Summary

We present new results from the Suzaku XIS observations of two nearby clusters of galaxies, the Centaurus cluster and the Fornax cluster. For the Centaurus cluster, we investigated the Doppler shift of the iron K lines to constrain the bulk velocity of the intracluster medium (ICM) in its core region. We found that there is no significant velocity gradient within the calibration uncertainty: the 90% upper limit on the line-of-sight velocity difference is |△ v|<1400 km s^-1, providing a tighter constraint than the previous observations. Regarding the Fornax cluster, we studied metal abundances of the ICM out to a large radius. K-lines of O and Mg were clearly resolved and the abundance profiles of O, Mg, Si, S and Fe were derived to high accuracy. The central γ <4’ region shows the Fe, Si, and S abundances to be ∼ 1 solar, while the Fe and Si abundances drop to about 0.5 solar in the outer region. O/Fe and Mg/Fe are about 0.4–0.5 and 0.7 in unit of the solar ratio, respectively, and do not show any significant radial gradient. Implications of the results on each cluster are briefly discussed.