New tests of physics with constrained large-scale structure simulations

典型的星系形成模拟对原始密度扰动采用随机相位，因此产生具有特定统计性质但在空间中位置任意的结构。相比之下，“约束”模拟与实际的局部宇宙的物质分布相匹配，允许模拟中的物体与观察到的星系和结构之间进行一对一的映射。该学生将利用一套名为CsiBORG的约束n体模拟（Bartlett et al. 2021）来设计和开展天体物理模型的新研究。这可能包括测试半解析星系形成模型，寻找暗物质和可见物质在宇宙时间内演化之间的相关性，开发或利用一种新的方法来识别局部宇宙中的空洞（Desmond et al. 2022），和/或量化由于附近结构而导致的局部测量宇宙膨胀率的潜在偏差。学生也可以进行自己的约束模拟，例如，加入流体动力学和辐射转移来探索局部宇宙的再电离历史，和/或约束局部宇宙中中性/分子氢的分布。

Typical simulations of galaxy formation adopt random phases for the primordial density perturbations and therefore produce structures with specified statistical properties but arbitrary positions in space. In contrast, "constrained" simulations match the matter distribution of the actual local Universe, allowing a one-to-one mapping between objects in the simulation and observed galaxies and structures. The student will leverage a suite of constrained N-body simulations called CsiBORG (Bartlett et al. 2021) to devise and carry out novel investigations of astrophysical models. This may include testing semi-analytic galaxy formation models, searching for correlations between the evolution of dark matter and visible matter over cosmic time, developing or exploiting a new method for identifying voids in the local Universe (Desmond et al. 2022), and/or quantifying potential bias in the locally measured expansion rate of the Universe due to nearby structure. There is also scope for the student to run their own constrained simulations, for example with the addition of hydrodynamics and radiative transfer to explore the reionization history of the local Universe, and/or to constrain the distribution of neutral/molecular hydrogen in the local Universe.