Modeling turbulent galaxy formation

伴随星系形成的宇宙气流具有高速度、跨越巨大尺度和高度湍流，但湍流对星系形成和相关过程的影响在很大程度上仍未被探索。这个项目是利用自洽和真实的高分辨率宇宙学模拟，系统地探索湍流及其对星系可观测属性的影响。它将解决解释跨宇宙时间的星系观测的几个基本问题。阿德勒天文馆将使用适用于全穹顶投影仪的高保真、科学准确的可视化计划模拟。这些可视化将可用于其他行星群，并可用于使用日益广泛的虚拟现实耳机的在线流媒体和观看，这可以提供一种新的有效的方式来接触到社会的广泛部分，包括学生和教育工作者，以引人入胜和易于访问的形式展示前沿研究的结果。该团队最近实施的亚格子湍流使这项工作成为可能，并将(1)调查滑盖不稳定性是否在冷气体吸积流中发展，以及湍流对关键性质的影响；(2)探索重力不稳定性和恒星反馈在驱动湍流中的作用；(3)量化湍流如何影响气体的密度结构、压力支持、恒星形成和混合过程；以及(4)探索恒星初始质量函数(IMF)的模型。这些方法使用了一种高效和多方面的反馈模型，包括宇宙射线的反馈、分子氢的形成、化学富集化和演化以及电离和远紫外光的辐射传输。这项研究探索了关键问题，包括控制星系气体供应的过程，恒星和星团形成效率的环境依赖性，以及不同恒星质量、金属度、形态和恒星形成历史的星系中的IMF。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Cosmic gas flows accompanying galaxy formation have high velocities, span enormous scales, and are highly turbulent, but the effects of turbulence on galaxy formation and associated processes are still largely unexplored. This project is a systematic exploration of turbulence and its effects on the observable properties of galaxies using self-consistent and realistic high-resolution cosmological simulations. It will address several fundamental issues in the interpretation of observations of galaxies across cosmic time. The Adler Planetarium will use high-fidelity, scientifically-accurate visualizations of the planned simulations suitable for full-dome projectors. These visualizations will be available to other planetaria, and for online streaming and viewing with the increasingly widespread virtual reality headsets, which can provide a new and effective way to reach broad segments of society, including students and educators, showing the results of cutting-edge research in an engaging and easily accessible form.The work is enabled by a recent implementation of subgrid turbulence by this team, and will (1) investigate whether slip sheet instabilities develop in cold gas accretion flows, and the effect of turbulence on key properties; (2) explore gravitational instability and stellar feedback in driving turbulence; (3) quantify how turbulence affects the density structure of gas, pressure support, star formation, and mixing processes; and (4) explore models of the initial mass function (IMF) of stars. The methods use a model of efficient and multi-faceted feedback, including feedback due to cosmic rays, formation of molecular hydrogen, chemical enrichment and evolution, and radiative transfer of ionizing and far-ultra-violet radiation. The study explores key issues, including the processes controlling gas supply to galaxies, the environmental dependence of star and star cluster formation efficiency, and the IMF in galaxies of different stellar masses, metallicities, morphologies, and star formation histories.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.