Constraining General Relativity and the neutrino mass with small scale galaxy clustering

该项目使用星系红移巡天的数据来限制宇宙结构的增长，这可以用来测试广义相对论和引力的替代理论，以及测量中微子质量的总和，粒子物理学的一个基本参数。星系团是现有最强大的宇宙学探测器之一，也是下一代星系红移调查的基础，如暗能量光谱仪（DESI）欧几里德卫星的使命将使现有数据集的规模增加一个数量级。这些数据集提供了极好的机会来了解更多关于管理我们宇宙的基本概念，但同时也带来了重大的计算和建模挑战，这需要新的创新分析技术。星系团的分析模型仅限于大（线性）尺度，忽略了大部分的宇宙学信息。而不是分析模型在这里，我们将使用N体模拟来比较观察到的星系集群。虽然N体模拟确实允许访问非线性尺度，但困难在于运行和处理此类模拟的计算成本以及星系-晕连接的建模。我们将基于晕占据分布（HOD）形式主义，结合星系聚集统计数据的分析和基于仿真器的建模，探索星系-晕连接的新模型。我们将把这个分析管道应用于DESI和Euclid数据集，以约束宇宙学模型。对星系团簇振幅的限制包含了中微子物理学的基本信息，DESI和欧几里得的限制有望在未来几年内测量中微子质量的总和，从而测量中微子质量等级

This project uses data from galaxy redshift surveys to constrain the growth of cosmic structure, whichcan be used to test General Relativity and alternative theories of gravity as well as measure the sumof the neutrino masses, a fundamental parameter of particle physics.The clustering of galaxies is one of the most powerful cosmological probes available and the nextgeneration of galaxy redshift surveys like the Dark Energy Spectroscopic Instrument (DESI) and theEuclid satellite mission will increase the size of current datasets by an order of magnitude. Thesedatasets provide fantastic opportunities to learn more about fundamental concepts governing ourUniverse, but at the same time pose significant computational and modelling challenges, whichrequire new and innovative analysis techniques. Analytic models for galaxy clustering are limited to large (linear) scales, leaving out most of thecosmological information. Instead of analytic models here we will use N-body simulations to compareto the observed galaxy clustering. While N-body simulations do allow to access non-linear scales, thedifficulties are the computational cost of running and processing such simulations as well as themodelling of the galaxy-halo connection. We will explore new models for the galaxy-halo connectionbased on the halo occupation distribution (HOD) formalism combined with analytic and emulatorbased modeling of galaxy clustering statistics. We will apply this analysis pipeline to the DESI andEuclid datasets, to constrain cosmological models. Constraints on the galaxy clustering amplitudecontain information on fundamental neutrino physics and constraints form DESI and Euclid areexpected to measure the sum of the neutrino masses and hence the neutrino mass hierarchy withinthe next couple of years