This thesis presents a detailed study of the impact of radio-AGN on star formation and the interstellar medium (ISM) of galaxies across cosmic time. To do this, this thesis uses far-IR/sub-mm data from the Herschel Space Observatory. I create a well-selected sample of 1599 radio sources using the NRAO VLA Sky Survey (NVSS) and Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) data in combination with the UKIRT Infrared Deep Sky Survey - Large Area Survey (UKIDSS - LAS) data. I find that the far-IR luminosities and dust temperatures of radio galaxies are lower in comparison to those of non-radio-detected galaxies. This luminosity deficit grows with increasing stellar mass. I argue that the reasons for these differences is probably due to indirect radio-AGN feedback, i.e. radio jets mechanically heat the halo-environment, preventing external sources of cold gas from entering the host and forming stars. The far-IR luminosity and dust temperature is found to decrease as a function of radio source size. I find the most likely explanation for this is jet-induced star formation while the jets are confined to the ISM. Finally, a method for identifying reliable high-z, star-bursting radio sources in the H-ATLAS is described with which statistically significant studies of radio-jet induced star formation may be undertaken.

This thesis presents observations and analysis relating to the understanding of processes that govern the formation and evolution of low mass galactic systems. In particular we have focused on separating out the contribution to the chemical and dynamical evolution of dwarf galaxies due to solely secular (internal) processes compared to external effects from the local environment a galaxy resides in. Our observational data focus on an extremely isolated dwarf galaxy, WLM, which we demonstrate has had a uniquely quiescent tidal history, thereby making it an excellent test case for such a study. With spectroscopic and photometric observations of the resolved stars and neutral gas in WLM we have been able to characterize the chemical, structural and kinematic properties of this gas rich dwarf galaxy. As WLM has not been subject to strong tidal or ram-pressure stripping of its stellar and gaseous populations, we have been able to compare the dynamical evolution and chemical history of WLM to theoretical models which are environment independent. A differential comparison of WLM to more environmentally processed dwarf galaxies in the Local Group has revealed that WLM's structural and dynamical state is far from the idealized picture of dIrrs as thin gas-rich rotating systems. The stellar component of WLM shows equal parts rotation and dispersion, and both the gaseous and stellar structural properties show an intrinsically thick axisymmetric configuration. The time evolution of the random (dispersion) component of the stellar orbital energy shows an increase with stellar age, which we show is consistent with secular processes alone - such as disk heating from giant molecular clouds and dark matter substructure. While the degree to which the thick structural and dynamically hot configuration for WLM is surprising, its chemical properties show remarkably consistent values with other galaxies of the same halo mass. Comparing the spatial chemical trends in WLM with other dwarf galaxies we identify a correlation between the strength of the radial abundance gradients and the angular momentum content of dwarf galaxies in the Local Group. Finally using a large sample of chemical abundance measurements in the literature for dwarf galaxies and star clusters, we demonstrate that their distributions of chemical elements all exhibit a binomial form, and use the statistical properties of the distributions to identify a new metric for differentiating low luminosity stellar systems. We further apply a simple binomial chemical evolution model to describe the self-enrichment and pre-enrichment in the two classes of objects, and suggest how this may be used to place constraints on the formation environments of globular clusters in particular. / Graduate

In this thesis I investigate the dynamics and stellar populations of a sample of 28 edge-on early-type (S0--Sb) disk galaxies, 22 of which host a boxy or peanut-shaped bulge. I begin by constructing mass models of the galaxies based on their observed photometry and stellar kinematics. Subject to cosmologically motivated assumptions about the shape of dark haloes, I measure in a purely dynamical way their stellar and dark masses. I make a preliminary comparison between the dynamically determined stellar masses and those predicted by stellar population models. I then compare the Tully-Fisher (luminosity--velocity) relations of the spirals and S0s in the sample. I show that S0s are systematically fainter at a given rotational velocity, but the amount by which they are fainter is less than expected by models in which they are the products of truncation of star formation in spirals. This raises the possibility that S0s are smaller or more concentrated than spirals of the same mass. I then study the vertical structure of the boxy and peanut-shaped bulges of a subset of the sample. Among this sample of five galaxies, I find one example in which the stellar populations show no evidence that the bulge and the disk formed in different processes, and in which the bulge is in perfectly cylindrical rotation, i.e. its line-of-sight velocity does not change with height above the disk. This galaxy is probably a pure disk galaxy. However, even with this small sample, I also show that cylindrical rotation and homogeneous stellar populations are not ubiquitous properties of boxy and peanut-shaped bulges. Finally I analyse central and radial trends in the stellar populations of the bulges of full sample of 28 galaxies. I find that, at a given velocity dispersion, the central stellar populations of these barred early-type disk galaxies are identical to those of elliptical galaxies, which suggests that secular evolution does not dominate the centre of these galaxies. However, the radial metallicity gradients are shallower than those of ellipticals. This is qualitatively consistent with chemodynamical models of bar formation, in which radial inflow and outflow smears out pre-existing gradients.