发表机构
Institute of Astronomy and Astrophysics, Academia Sinica; Department of Physics and Astronomy, Seoul National University; School of Physics, Korea Institute for Advanced Study（中央研究院天文及天文物理研究所; 首尔大学物理天文学系; 韩国高等科学研究院物理学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究原初密度 - 势交叉相关系数与自旋因子分布的关系，通过初始密度 - 势交叉相关系数q推导自旋因子τ均值和方差的解析表达式，分析多元宇宙模拟数据验证其有效性，或可借此从星系大小分布确定q并约束早期宇宙物理。
AI 中文摘要
近期研究表明，可见星系的关键特性与其宿主暗物质晕的角动量密切相关。根据线性潮汐扭矩理论，晕角动量与原初自旋因子τ成正比，τ由初始密度和势黑塞矩阵主轴的不对准程度定义，数值实验发现其遵循伽马分布。本研究通过初始密度 - 势交叉相关系数q启发式地推导了τ均值和方差的解析表达式。分析多元宇宙模拟数据集表明该表达式普遍有效，这可能使我们能从星系大小分布确定q，进而通过启发式模型约束早期宇宙物理。
英文摘要
Recent studies have revealed that the key properties of visible galaxies like their optical sizes, stellar ages, star formation rates and morphologies are closely linked with the angular momenta of their host dark matter halos. According to the linear tidal torque theory, the halo angular momentum, as a conserved quantity, is directly proportional to the primordial spin factor, $τ$, defined as the degree of misalignment between the principal axes of the initial density and potential Hessian matrices, which were found by numerical experiments to follow a Gamma distribution, fully characterized by its mean and variance. In this study, we heuristically develop an analytic expression for the mean and variance of $τ$ in terms of the initial density-potential cross-correlation coefficient, $q$. Analyzing a dataset from the Multiverse simulations performed for both of the flat $Λ$CDM and $w$CDM cosmologies, we prove that this analytic expression is universally valid in describing how the mean and variance of $τ$ change with $q$, regardless of the smoothing scales for both of the cosmologies. Given the prior finding that the $τ$-distribution can be reconstructed from the observable galaxy size distribution, this universal analytic expression may allow us to determine $q$ from the same observable via the mean and variance of $τ$. We discuss a possibility of constraining the early universe physics from the reconstructed $q$ via our heuristic model, without suffering from cosmological degeneracies.
CommentsAccepted for publication in ApJ, revised version after referee's review, minor revisions, 6 figures, 3 tables
