Nykytyuk T. Modelling and analysis of the matter exchange effect on the chemical evolution of galaxies and their environment

The thesis is dedicated to study of modelling and analysis of the matter exchange effect on the chemical evolution of galaxies as well as on the chemical composition of intergalactic gas surrounding them. The possibility of galactic halo formation through mergers of fragments has been considered - under condition that a halo stellar population is a mixture of stars which were formed in individual fragments before their merger. Within the framework of such scenario the chemical evolution of merging fragments have been calculated and metallicity distribution functions of halo field stars and halo globular clusters have been obtained for 7 galaxies including the our Galaxy. A chemical evolution of Galactic disk has been investigated within the framework of open two-zone model of chemical evolution of the galaxies. The Galactic evolution of magnesium, silicium, oxygen and iron for the thick and thin disks of the Galaxy as well as the thin disk metallicity distribution function has been calculated.The parameters of star formation history have been obtained for the thin and thick disks of the Galaxy. It has been found that a gas infall plays an important role in arising of chemical distinctions between the thin and thick disks of the Galaxy. The values of column density and redshift of hydrogen and metal lines in Ly alpha forest clouds and metal absorbtion systems in the redshift range z from 0 up to ~ 4.3 towards 19 quasars were collected from the literature. Observation data analysis has demonstrated that predecessors of galaxies can play an important role in metal enrichment of intergalactic gas.