Extremely, deep milliarcsecond radio observations of the high redshift radio source population

The SKA will routinely survey the radio continuum sky at microJansky sensitivities. We know from the deepest observations made to date using the current state-of-the-art radio facilities, such as e-MERLIN/VLA/EVN, that the extragalactic 'SKA-sky' will be dominated by a mixture of intense star-forming galaxies and radio-quiet AGN. These sources are typically situated between redshifts of 0.5 and 4, have flux densities less than 100microJy and in many cases are luminous merging galaxies often hosting co-evolving star-formation and accretion activity. Obtaining a characterisation of this radio source population with existing observations is vital to help guide the development of the key science programmes for the SKA. As part of this process the e-MERGE consortia are in the process of obtaining one of the deepest-ever high resolution radio studies of this source population via a combination of extremely deep e-MERLIN, VLA and EVN observations of the GOODS-N (formally known as HDF-N) field. These observations will reach sub-microJansky sensitivities and uniquely will have milliarcsecond resolving power. This high angular resolution, provided by long baseline interferometry (EVN and e-MERLIN) allow the spatial structure of this radio source population to be deconvolved and the contributions of star-formation and accretion to be separated. As part of a wider international effort during this PhD project you will work to analysis these new e-MERLIN/VLA & EVN observations to characterise the microjansky radio source population and use observational methods to separate the contributions, and hence co-evolution, of accretion and star-formation in the high redshift universe. In particular this project will focus on using stacking analysis methods to probe the radio source size population at the faintest (nJy) flux densities. Initially this programme will focus on data in-hand observed in the GOODS-N field before being extended to the COSMOS filed via exsiting VLA and upcoming eMERLIN+EVN(+ potentially AVN) observations.