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    PR # 31229                                                                   
     Study of small groups of galaxies is important for cosmology and gala       
     xy formation. ROSAT observations show that these groups of galaxies a       
     re surrounded by large dark matter halos. Substantial fraction of mas       
     s of the universe is stored in these small groups. X-ray obserbations       
      of these small groups of galaxies will allow direct estimation of th       
     e dark matter mass associated. Previous observations of small samples       
      of such poor groups show much lower metallicity than clusters of gal       
     axies. Yet more samples are required to reach conclusion. Metallicity       
      will tell us the galaxy evolution and formation of such groups.            
                                                                                 
                                                                                 
                                                                                 
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