Optimal estimation of higher-order correlation functions in galaxy surveys

The proposed PhD project in cosmology will estimate higher-order correlation functions in large galaxy surveys in order to test inflationary theory, while also advancing diagnostic tools for large-scale structure analysis. Exploiting a state-of-the-art bispectrum estimation pipeline developed for full-sky Planck CMB (and optimised for many-core supercomputer architectures), the goal is to optimally extract the projected bispectrum from SDSS and other galaxy surveys, preparing flexible and highly efficient tools applicable to next generation experiments like Euclid. Combining with corresponding constraints from the CMB, this work is expected to provide the most precise measurements of non-Gaussianity available. These bispectrum results will be combined with the power spectrum in a polyspectra analysis to test against predictions from phenomenological inflation and other models from fundamental cosmology. Cross-correlators of the bispectrum between large-scale structure and the CMB will also be examined, including gravitational lensing, an investigation motivated by the need to remove degeneracies that appear in cosmological parameter estimation using only the power spectrum. This area of research is very timely and topical within mainstream cosmology, providing important diagnostic tools for huge galaxy surveys in which STFC participates, such as DES, DESI, LSST and Euclid.