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UBC Theses and Dissertations

The faint extragalactic radio sky Vernstrom, Tessa


The radio sky covers a large range of sources, from small single galaxies to large clusters of galaxies and the space between them. These sources consist of some of the most powerful objects in the Universe, as well as diffuse weak emitters. Understanding the radio sky tells us about how galaxies have evolved over time, the different kinds of galaxy populations, the star formation history of the Universe, and the role of magnetism, as well as details of large-scale structure and clustering. Advancements in radio telescopes now allow us to push observational limits to new depths, probing fainter galaxies and farther back in cosmic time. We use a multi-pronged approach to examine several aspects of the faint extragalactic radio sky. Using new deep data from the Karl G. Jansky Very Large Array telescope, combined with the confusion analysis technique of P(D), we obtain the deepest estimates of the source count of individual radio galaxies and their contribution to the cosmic radio background temperature. Additionally, these data are used to catalogue the individual galaxies in order to study characteristics such as source size, spectral dependence, galaxy type, and redshift. We then examine the contribution from extended large-scale diffuse emission to the radio sky using data from the Australia Telescope Compact Array. This yields constraints on the total emission from such sources, including galactic halos, galaxy cluster halos and relics, and the inter- and intra-cluster medium. Finally, we investigate the radio angular power spectrum using interferometric data. These measurements show the fluctuations coming from the unresolved radio background as a function of angular scale. Together these studies present the deepest constraints available for the faint radio sky across a range of statistical areas. The measurements obtained here provide constraints on the evolving population of galaxies through their radio emission in order to further our knowledge of galaxy evolution in general.

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