Discovery of a large-scale abundance gradient in the cluster of galaxies AWM 7 with ASCA

A large-scale gradient in the metal abundance has been detected with ASCA from an X-ray bright cluster of galaxies, AWM 7. The metal abundance shows a peak of 0.5 solar at the center and smoothly declines to less than or similar to 0.2 solar at a radius of 500 kpc. The gas temperature is found to be constant at 3.8 keV. The radial distribution of iron can be fitted with a beta model with beta similar to 0.8 assuming the same core radius (115 kpc) as that of the intracluster medium. The metal distribution in AWM 7 suggests that the gas injected from galaxies is not efficiently mixed in the cluster space and traces the distribution of galaxies.