Optimal estimation of higher-order correlation functions in galaxy surveys

拟议中的宇宙学博士项目将估算大型星系调查中的高阶相关函数，以测试暴胀理论，同时也将推进大规模结构分析的诊断工具。利用为普朗克CMB开发的最先进的双谱估计管道（并针对多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，准备适用于欧几里得等下一代实验的灵活高效的工具。结合来自CMB的相应约束，这项工作有望提供最精确的非高斯性测量。这些双谱结果将与多谱分析中的功率谱相结合，以检验来自现象学暴胀和其他基础宇宙学模型的预测。大尺度结构和CMB之间的双谱交叉相关也将被研究，包括引力透镜，这一研究的动机是需要消除仅使用功率谱进行宇宙学参数估计时出现的简并。这一领域的研究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（如DES， DESI， LSST和Euclid）提供了重要的诊断工具。

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.