Host galaxies and environments of compact extragalactic radio sources

The main goal of this thesis is to study the interrelation of powerful radio sources with their hosts. The objects of study are GPS and CSS sources. Due to their small size, GPS/CSS sources are excellent probes of this relation. Furthermore, their young age allows us to compare them to the larger, old radio sources and establish a time-line evolution of this relation. This thesis combines imaging and spectroscopy of GPS/CSS sources at different wavelengths, and all our studies lead to the same conclusion: the presence and expansion of powerful radio sources clearly affect the properties and evolution of their hosts. All chapters of the thesis (excluding the sample studies) find evidence of strong interaction between the host and the radio source. Furthermore, the radio source and host can significantly affect each others evolution. However, this influence takes place in different ways. The influence that the host has on the radio source is somehow indirect. However it can completely change its destiny: depending of the contents, distribution and density of the gas, the radio source will die early, expand and grow into the large FR sources, or remain confined inside its host. In contrast, the influence of the radio source on its host seems to be more direct and takes place during its expansion through the host: the radio source will affect the kinematics and ionization of the emission line gas, and may change the star formation history of the host. Briefly, the main results that lead to this conclusion are: (1) Presence of shock ionized gas in 3C67, 3C277.1 and 3C303.1 (Chapter 4). (2) HI gas associated to the emission line gas in 3C~49 and 3C 268.3 and the presence of outflows in B2050+364 (Chapters 5 and 6). (3) Possible events of star formation related to the triggering of the radio source and findings of jet induced star formation in 1814--637 and 3C 303.1, which is also the source showing the strongest contribution from shocks to the ionization of the emission line gas (Chapter 7)