Optimal estimation of higher-order correlation functions in galaxy surveys

拟议的宇宙学博士项目将估计大型星系调查中的高阶相关函数，以测试膨胀理论，同时还将推进大规模结构分析的诊断工具。利用为全天空普朗克CMB开发的最先进的双谱估计管道（并针对众核超级计算机架构进行了优化），目标是从SDSS和其他星系调查中最佳地提取投影双谱，准备适用于下一代实验（如欧几里得）的灵活和高效的工具。结合CMB的相应约束，这项工作有望提供最精确的非高斯测量。这些双谱结果将与多谱分析中的功率谱相结合，以检验唯象暴胀和其他基础宇宙学模型的预测。大尺度结构和宇宙微波背景之间的双谱的交叉放大器也将被检查，包括引力透镜，一个调查的动机是需要删除退化出现在宇宙学参数估计只使用功率谱。这个研究领域在主流宇宙学中是非常及时和热门的，为STFC参与的大型星系调查提供了重要的诊断工具，如DES，DESI，LSST和欧几里得。

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.