Radiative feedback from stars and galaxies has been proposed as a potential solution to many of the tensions with simplistic galaxy formation models based on $Λ$CDM, such as the faint end of the UV luminosity function. The total energy budget of radiation could exceed that of galactic winds and supernovae combined, which has driven the development of sophisticated algorithms that evolve both the radiation field and the hydrodynamical response of gas simultaneously, in a cosmological context. We probe self-feedback on galactic scales using the adaptive mesh refinement, radiative transfer, hydrodynamics, and $N$-body code. Unlike previous studies which assume a homogeneous UV background, we self-consistently evolve both the radiation field and gas to constrain the halo baryon fraction during cosmic reionization. We demonstrate that the characteristic halo mass with mean baryon fraction half the cosmic mean, $M_{\mathrm{c}}(z)$, shows very little variation as a function of mass-weighted ionization fraction. Furthermore, we find that the inclusion of metal cooling and the ability to resolve scales small enough for self-shielding to become efficient leads to a significant drop in $M_{\mathrm{c}}$ when compared to recent studies. Finally, we develop an Artificial Neural Network that is capable of predicting the baryon fraction of haloes based on recent tidal interactions, gas temperature, and mass-weighted ionization fraction. Such a model can be applied to any reionization history, and trivially incorporated into semi-analytical models of galaxy formation.
Cosmic Reionization On Computers: Baryonic Effects on Halo Concentrations During the Epoch of Reionization
重子既通过绝热收缩增加晕的浓度，又通过反馈过程排出质量。然而，在再电离时期普遍存在的辐射场如何影响暗物质晕中浓度的演化还不是很清楚。我们研究重子物理在再电离时代如何修改计算机宇宙再电离（CROC）模拟中的暗物质晕结构。我们使用两种不同的措施晕浓度量化的影响。我们比较浓度的晕之间匹配的全物理模拟和暗物质只有模拟$5 \leq z \leq 9$之间具有相同的初始条件。全物理模拟中的重子确实会将物质拉向中心，与仅暗物质模拟相比，增加了最大圆周速度。然而，它们的总体影响要比所有重子简单地集中在中心的情况小得多，这表明加热过程有效地抵消了冷却效应。最后，我们表明，在$z\approx5$晕浓度的重子效应是相对不敏感的再电离历史的环境变化。这些结果是有关模型的星系晕连接在再电离的时代。
再电离是自复合以来宇宙中唯一的相变，是重子物质宇宙历史中的一个关键事件。我们得出，在大规模的偏置膨胀的背景下，在大规模分布的星系再电离时代的印记，并确定两个特别重要的贡献。首先，CMB光子与自由电子的康普顿散射导致重子流体上的拖曳力。这种阻力引起重子和CDM之间的相对速度，这是相同的数量级的原始诱导的相对速度，并进入相对速度的演化计算玻尔兹曼代码。这导致了一个独特的贡献，星系的偏见涉及的物质速度平方。第二个重要的效应是电离辐射场通过辐射传递效应对星系密度的调制，这在偏置膨胀中被所谓的高阶导数项所捕获。我们使用BOSS DR 12星系样本的功率谱来约束这两个印记。虽然它们不会导致重子声学振荡尺度的变化，但包括这些项对于来自星系功率谱形状的无偏宇宙学约束是重要的。
Co-evolution of baryons and dark matter halos of LYRA dwarf galaxies
Durham University（杜伦大学）；European Southern Observatory（欧洲南方天文台）；Stockholm University（斯德哥尔摩大学）；University of Hawaii（夏威夷大学）；Max-Planck-Institut für Astrophysik（马克斯·普朗克天体物理学研究所）
Introducing the Lumina project: large-volume radiation-hydrodynamic simulations of the epochs of hydrogen and helium reionization
The University of Texas at Dallas（德克萨斯大学达拉斯分校）；Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research（麻省理工学院，卡弗里天体物理与空间研究所）；Department of Physics, Massachusetts Institute of Technology（麻省理工学院物理系）；York University（约克大学）；Max Planck Institute for Astrophysics（马克斯·普朗克天体物理研究所）
