Supervisor: Dr Roger Clowes
In 2013 Roger Clowes and collaborators discovered “the largest structure [known] in the early universe” – a Large Quasar Group at redshift z=1.27. It received widespread media coverage across the world. Previously, Roger Clowes and Luis Campusano had discovered what at the time was the largest structure known – a Large Quasar Group at redshift z=1.28. Rather curiously, these two structures are next to each other but so far appear not to connect. Separately and together they represent a challenge to the Cosmological Principle (CP) – the simplifying assumption that is the foundation of the whole of modern cosmology. Other workers have also found results that appear to challenge the CP, such as the correlation of the polarisation vectors of quasars across very large scales.
Although the CP has been a fundamental assumption in cosmology since 1917, it is only in relatively recent times that technology (modern telescopes, computers, huge databases) allows it to be tested. This project is to test further the CP using a wide range of probes -quasars, galaxies, gamma-ray bursters, quasar polarisation, and the CMB. Also of interest is the environmental influences of such large structures on the properties of quasars and galaxies.