حلیمه السادات میر آقایی جعفری

The evolution of galaxies and their super massive black holes depend on the environment. We studied active galactic nucleus (AGN) activity in different environments using two samples of AGN selected at optical and radio bands. The fractions of galaxies hosting AGN have been compared for samples of void, isolated, group member, and the brightest group galaxies. Galaxies in voids show significantly lower stellar ages, concentrations, colors, and surface mass densities compared to the isolated galaxies and galaxies in groups. To study pure environmental effects, the biases caused by the stellar mass and galaxy type quantified by 4000 Å break strength have been removed. While the results confirm no dependence of the optical AGN activity on environment in blue and green galaxies, a higher fraction of optical AGN has been observed for the massive red galaxies in voids compared to the galaxies in dense environments. The radio-mode AGN activity increases in the dense environment for red galaxies. No changes in the radio-loud AGN fraction have been observed for the blue and green galaxies. The results show that the effect of environment on AGN activity depends on the properties of the host galaxy and it is not significant in the presence of cold gas in galaxies.