AI 中文总结
研究中性氢（HI）与晕的联系，利用GAEA半解析模型预测HI质量函数等，刻画其关系、演化及散射，确定次要依赖性，编码相关关系和散射于处方，能构建模拟目录助力SKA相关测量与调查。
AI 中文摘要
中性氢（HI）的红移21厘米线是大尺度结构的有力追踪器，再电离后HI强度映射正成为一种有竞争力的宇宙学探测器，其解释需要描述HI如何分布在星系和暗物质晕中。我们刻画了HI-晕质量关系、其红移演化及其固有散射，确定了其次要依赖性。我们使用更新的星系演化与组装（GAEA）半解析模型，应用于千禧年-I和千禧年-II模拟，预测从当今到红移\(z\simeq5\)的HI质量函数（HIMF）和HI-晕质量关系。在\(z = 0\)时，该模型再现了观测到的HIMF及其按宿主晕质量的分解。HI-晕质量关系的中值随晕质量增加，在\(10^{11.7}\,M_\odot\)附近达到峰值，随着中心星系因活动星系核的反馈而被抑制而下降，并在卫星占主导时再次上升，在高红移时接近单一幂律。我们表明，约0.5 dex的大量散射不是随机的，而是由晕的组装控制：在固定质量下，自旋更高、形成更晚且集中度更低的晕系统地富含HI，自旋与集中度或形成时间一起解释了部分散射，留下约0.3 dex的固有色散。我们将中值关系、这些次要趋势和固有散射编码在一个紧凑的、基于物理的处方中，该处方完全根据暗物质晕目录中可用的量来表示。此处方再现了完整的散射，并能够构建大体积的21厘米模拟目录，用于解释使用SKA前身设施（如MeerKAT）进行的正在进行的强度映射测量，并为使用SKA进行的即将到来的调查做准备。
英文摘要
The redshifted 21-cm line of neutral hydrogen (HI) is a powerful tracer of large-scale structure, and post-reionization HI intensity mapping is emerging as a competitive cosmological probe whose interpretation requires a description of how HI populates galaxies and dark matter halos. We characterize the HI--halo mass relation, its redshift evolution, and its intrinsic scatter, identifying its secondary dependences. We use the updated GAlaxy Evolution and Assembly (GAEA) semi-analytic model, applied to the Millennium-I and Millennium-II simulations, to predict the HI mass function (HIMF) and the HI--halo mass relation from the present day to redshift $z\simeq5$. At $z=0$, the model reproduces the observed HIMF and its decomposition by host-halo mass. The median HI--halo mass relation rises with halo mass, peaks near $10^{11.7}\,M_\odot$, declines as central galaxies are quenched by feedback from active galactic nuclei, and rises again where satellites dominate, approaching a single power law at high redshift. We show that the substantial scatter, of about 0.5 dex, is not random but is governed by halo assembly: at fixed mass, higher-spin, later-forming, and less-concentrated halos are systematically HI-richer, with spin together with either concentration or formation time accounting for part of this scatter and leaving an intrinsic dispersion of about 0.3 dex. We encode the median relation, these secondary trends, and the intrinsic scatter in a compact, physically motivated prescription expressed entirely in terms of quantities available in dark-matter halo catalogs. This prescription reproduces the full scatter and enables the construction of large-volume 21-cm mock catalogs for interpreting ongoing intensity-mapping measurements with SKA precursor facilities, such as MeerKAT, and for preparing for forthcoming surveys with the SKA.
Comments14 Pages, 10 figures, 3 tables, 1 appendix
