We model the distribution of the observed profiles of 21 cm line emission from neutral hydrogen (HI) in central galaxies selected from a statistically representative mock catalog of the local Universe in the Lambda-cold dark matter framework. The distribution of these HI velocity profiles (specifically, their widths $W_{50}$) has been observationally constrained, but has not been systematically studied theoretically. Our model profiles derive from rotation curves of realistically baryonified haloes in an N-body simulation, including the quasi-adiabatic relaxation of the dark matter profile of each halo in response to its baryons. We study the predicted $W_{50}$ distribution using a realistic pipeline applied to noisy profiles extracted from our luminosity-complete mock catalog with an ALFALFA-like survey geometry and redshift selection. Our default mock is in good agreement with observed ALFALFA results for $W_{50}\gtrsim700$ km/s, being incomplete at lower widths due to the intrinsic threshold of $M_r\leq-19$. Variations around the default model show that the velocity width function at $W_{50}\gtrsim300$ km/s is most sensitive to a possible correlation between galaxy inclination and host concentration, followed by the physics of quasi-adiabatic relaxation. We also study the excess kurtosis of noiseless velocity profiles, obtaining a distribution which tightly correlates with $W_{50}$, with a shape and scatter that depend on the properties of the turbulent HI disk. Our results open the door towards using the shapes of HI velocity profiles as a novel statistical probe of the baryon-dark matter connection.
我们从斯隆数字巡天数据发布16（SDSS DR 16）的调查，也从千年模拟提取空目录。我们的重点是我们的比较分布的星系比$M_r < -18$内部的空洞和研究的平均间隔的空洞星系，距离空洞中心，和径向密度分布。我们发现，空洞星系的平均分离取决于空洞的大小，因为较大的空洞有较低的平均分离在两个样本。然而，在观察样本中的空洞星系似乎有更大的平均距离比模拟的任何给定的空洞大小。此外，观察到的空洞星系往往比模拟中的更靠近空洞中心。这种差异也表现在空隙的密度分布中。无论孔隙大小如何，真实孔隙分布的中心密度都高于预测模拟目录中的中心密度。
The Cosmic Rush Hour: Rapid Formation of Bright, Massive, Disky, Star-Forming Galaxies as Signatures of Early-Universe Physics
Massachusetts Institute of Technology（麻省理工学院）；Center for Astrophysics | Harvard & Smithsonian（天体物理中心 | 哈佛与史密森尼学会）；The University of Texas at Austin（德克萨斯大学奥斯汀分校）；University of Cambridge（剑桥大学）
