******************************************************
   PR # 41277
   Poor clusters and rich clusters have similar iron abundance about 0.3
   solar, while groups of galaxies have very low iron abundance about
   0.1. This difference may be the result of different star formation
   history. The ratio of silicon and iron abundance is the key parameter
   to show the contribution of SNIa and SNII. We propose to observe two
   groups of galaxies, RXJ1736.4+6804 and RXJ1755.8+6236 to determine
   this parameter.
  ******************************************************