any systematic errors in the GXE. For the inner 50 kpc most metal abundances are tightly restricted thanks to the high energy resolution of the Suzaku XIS while in the outer regions the abundances are less well constrained due to the GXE systematic errors. However, the Ne abundance is not reliable because Ne lines are confused with Fe-L lines. Furthermore, only upper limits could be obtained on the O and Ne abundances in the 60–140 kpc region, since their uncertainties are very large due to contamination by the Galactic emission. It can been seen that all the metal abundances are 0.7–2.5 solar in the central region, and decrease down to 0.3–1.0 solar towards the outer region. In the central region, the O and Fe abundances are about 1.2 times larger than that obtained with the RGS (Xu et al. 2002). Figure 6 shows confidence contours of O and Mg abundances against the Fe abundance. The O and Mg to Fe abundance ratio are particularly important to constrain the contribution of different types of supernovae. Although the individual errors for each metal abundance are large, the abundance ratios are constrained well, especially for the Mg to Fe abundance ratio in the 