Simulating Faintest Galaxies in the JWST Era

宇宙再电离的研究——早期星系的高能辐射使大量宇宙气体电离的过程——是近十年来天体物理学研究中最有前途的领域之一。在这个十年结束的时候，再电离时代的观测能力将会有惊人的提高。这一突破是由詹姆斯·韦伯太空望远镜（JWST）引领的，它是美国宇航局在这个和下一个十年的旗舰任务，以及随后的其他几项观测发展。所有这些观测探测器都将充斥着高质量的观测数据，除非观测进展能够得到理论上的相应进展，而数值模拟是主要工具，否则这些观测数据的覆盖范围将是有限的。JWST的主要科学目标之一是将高红移星系的探测极限推到足够微弱的水平，在那里光度函数有望“翻转”。该项目的主要科学目标是利用Blue Waters的千万亿级能力来探索星系紫外线亮度函数微弱末端的转换的物理机制。由于JWST的范围足以探测到集群透镜“前沿场”的预期周转，理论必须准备好用适当的解释工具来面对这种观察。这个项目是计算机宇宙再电离（CROC）项目的一部分。该项目的最终目标是开发模拟技术，以便能够在超过100个移动Mpc的模拟体积和接近100个物理单位的空间分辨率中完全模拟所有相关的物理，从辐射转移到气体动力学和恒星形成，从而覆盖与模拟再电离相关的空间、时间和质量尺度的全部范围。就更广泛的影响而言，该项目将作为高性能计算研究生专业培训的工具。此外，通过芝加哥大学和阿德勒天文馆之间的紧密联系，该项目具有巨大的推广潜力。

The study of cosmic reionization -- the process of ionization of the bulk of cosmic gas by high energy radiation from early galaxies -- is one of the most promising areas of astrophysical research in the current decade. The end of this decade will see an amazing increase in observational capabilities for the epoch of reionization. The breakthrough is spearheaded by the James Webb Space Telescope (JWST), the flagship NASA mission for this and next decade, as well as several other observational developments to follow. All there observational probes will flood the field with high quality observational data, whose reach will be limited unless the observational progress can be met with equivalent advances in theory, of which numerical modeling is a primary tool.One of the JWST primary science goals is to push the detection limit of high redshift galaxies to sufficiently faint levels, where the luminosity function is expected to "turn over". The primary scientific goal of this project is to use the petascale capabilities of Blue Waters to explore the physical mechanisms for the turnover at the faint end of the galaxy UV luminosity function. Since the JWST reach is sufficient to detect the expected turnover in cluster-lensed "Frontier Fields", theory must be ready to confront such observations with adequate interpretive tools. This project is part of the Cosmic Reionization On Computers (CROC) project. The ultimate goal of the project is to develop simulation technology to be able to model fully all relevant physics, from radiative transfer to gas dynamics and star formation, in simulation volumes of over 100 comoving Mpc and with spatial resolution approaching 100 pc in physical units, thus covering the full range of spatial, temporal, and mass scales relevant to modeling reionization.In terms of broader impacts, this project will serve as a vehicle for professional training of graduate students in high performance computing. In addition, this project has substantial outreach potential via a strong connection between the University of Chicago and Adler Planetarium.