Relative abundance of elements in quasi-stellar objects and evolution of galaxies

Abundance ratios in QSOs Q 1246-057, 0453-423, PKS 0528-250, Q 0002-422, and PKS 2126-158 have been calculated by the method of curve of growth. Relative abundance of carbon with respect to silicon has been calculated in the QSOs Q 1246-057, PKS 0528-250, Q 0002-422, and PKS 2126-158. Relative abundance of aluminium with respect to silicon has been calculated in the QSOs PKS 0528-250 and PKS 2126-158. Relative abundance of iron with respect to magnesium has been also calculated in the QSOs Q 0453-423 and Q 0002-422. The ratiosN(C)/N(Si) andN(Al)/N(Si) andN(Fe)/N(Mg) in QSOs considered as a class are 3.45±2.33, 0.063±0.054, and 1.08±0.70, respectively.The ratiosN(C)/N(Si) andN(Al)/N(Si) show a mild trend of increase with decreasing emission redshift. On the other hand, the ratioN(Fe)/N(Mg) shows a mild trend of decrease with decreasing emission redshift. This suggests the possibility of the chemical evolution of QSOs.The comparison ofN(C)/N(Si), the relative abundance of carbon-one of the four most plentiful elements — with respect to silicon in QSOs and normal galaxies suggests that QSOs might belong to an early phase in the evolutionary sequence of galaxies and that they evolve chemically into normal galaxies in course of time.Mrs. Alpana Gangopadhyaya after marriage.