论文标题
暗物质光环中原子氢含量的理论模型
Theoretical Models of the Atomic Hydrogen Content in Dark Matter Halos
论文作者
论文摘要
原子氢（H I）气体主要居住在宇宙回离后暗物质晕中，是恒星形成的燃料。它与主机光环的属性的关系是了解宇宙H I分布的关键。在这项工作中，我们提出了H-Halo关系的灵活的经验模型。在此模型中，虽然H I质量主要取决于宿主光环的质量，但对其他光环特性也有次要依赖性。我们将我们的模型应用于Arecibo快速遗产Alfa调查（alfalfa）的观察数据，并发现它可以成功适应宇宙H i的丰度（$ω_{\ rm hi} $），平均H I-Halo质量关系$ \ langle $ \ langle m _ {聚类。苜蓿数据的最佳fit具有较高置信度的拒绝，该模型没有H i质量的次级光环依赖性和对Halo Spin参数（$λ$）的二次光环依赖性（$ a_ {1/2} $）和HALO浓度（$ C_ {$ C_ {\ rm rm rm vir} $）。为了从流体动力学模拟的角度来解释这些发现，插图模拟证实了h i质量对次级光环参数的依赖性。但是，Illustristng的结果表明，对$λ$的依赖性很强，并且对$ c _ {\ rm vir} $和$ a_ {1/2} $的弱依赖性，并且还可以预测，在大尺度上，H I聚集的价值比观察值大得多。模拟和观察之间的这种差异需要改善理论和观察方面的H-HALO关系。
Atomic hydrogen (H I) gas, mostly residing in dark matter halos after cosmic reionization, is the fuel for star formation. Its relation with properties of host halo is the key to understand the cosmic H I distribution. In this work, we propose a flexible, empirical model of H I-halo relation. In this model, while the H I mass depends primarily on the mass of host halo, there is also secondary dependence on other halo properties. We apply our model to the observation data of the Arecibo Fast Legacy ALFA Survey (ALFALFA), and find it can successfully fit to the cosmic H I abundance ($Ω_{\rm HI}$), average H I-halo mass relation $\langle M_{\rm HI}|M_{\rm h}\rangle$, and the H I clustering. The bestfit of the ALFALFA data rejects with high confidence level the model with no secondary halo dependence of H I mass and the model with secondary dependence on halo spin parameter ($λ$), and shows strong dependence on halo formation time ($a_{1/2}$) and halo concentration ($c_{\rm vir}$). In attempt to explain these findings from the perspective of hydrodynamical simulations, the IllustrisTNG simulation confirms the dependence of H I mass on secondary halo parameters. However, the IllustrisTNG results show strong dependence on $λ$ and weak dependence on $c_{\rm vir}$ and $a_{1/2}$, and also predict a much larger value of H I clustering on large scales than observations. This discrepancy between the simulation and observation calls for improvements in understanding the H I-halo relation from both theoretical and observational sides.
