| The aim of this thesis it twofold: to study the general evolution of galaxies in groups over a large range of redshifts up to z = 0.5 and to analyze the characteristics of the radio phenomenon. We obtained CCD photometry of fields containing the radio sources in the B and V bands for the low redshift sample (0.03 ;The same data offers an excellent opportunity to study how the environment affects the formation as well as the evolution of the radio phenomenon and also the manifestation of its extreme radio activity. We shall concentrate on a series of questions in the following order: Which type of galaxy is a candidate for becoming a radio source? What are the environmental properties of those galaxy candidates? How does the environment itself affect the radio activity over cosmological timescales? What triggers the radio activity, and following that, how does the radio activity manifest itself? And finally, once the radio activity has started, how does this affect the properties of its host galaxy?;While the evolution of galaxies is dependent on their environments, the environment itself may evolve. Therefore, we concentrate on three major questions: What exactly is evolving with time? How is this evolution dependent on the properties of the environment? And finally, how does the environment affect the evolution of the galaxy morphologies? In this analysis, we measure the following quantities for all groups: the group richnesses, the positions of all galaxies, their magnitudes and colors. From this we derive the luminosity functions, and the density profiles of the groups. Finally we determine the fraction of blue galaxies in the groups at higher redshifts, and we discuss their nature. |
