NSF-BSF: The Physics of Multiphase Gas Streams feeding Galaxies from the Cosmic Web

在过去的二十年里，星系形成的一幅连贯的图景已经出现，气体从星系间介质(IGM)通过一系列狭窄的细丝和薄片组成的网络流入质量较大的暗物质晕，这些网络共同构成了“宇宙网”。这种气体吸积为恒星的形成提供了燃料，设定了盘状星系的角动量和大小，并驱动了湍流和盘状不稳定性。如果不详细了解这一吸积过程，我们就不能完全理解星系的演化。然而，对这种流入的数值模拟是极具挑战性的。这个研究小组将通过一套扩展的宇宙学磁流体力学模拟来解决这些缺点，这些模拟旨在解决细丝和IGM的问题，以准确地模拟它们的演化，并探索星系从其形成的早期阶段如何馈送的详细物理学。这项工作将为两名研究生提供指导和培训。该团队还将为耶鲁大学的科学之路项目创建一个宇宙学模块，并为高中生提供为期两周的免费夏季STEM项目。拟议的模拟将在所有相关尺度上解析气体的多相结构，从MPC大小的宇宙薄片和细丝到在气流和气流供给盘中形成的致密气体团块(数十秒)。这种全面的理论分析有望在宇宙学背景下重塑对星系形成的理解，并加深我们对多相等离子体物理学的理解。它也非常及时地帮助解释星系、莱曼-阿尔法斑点、莱曼-阿尔法森林和无金属莱曼极限系统周围气体的当前和即将到来的观测数据。此外，这项研究还旨在提高对高z盘星系如何获得角动量以及哪些机制负责触发湍流和维持剧烈不稳定性的理解。作为这项研究的一部分运行的所有模拟都将公开。该团队还将建立分析模型，概括他们的发现并阐明星系形成的物理学。这一奖项反映了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。

Over the past two decades, a coherent picture of galaxy formation has emerged whereby gas flows into massive dark matter halos from the Intergalactic Medium (IGM) via a network of narrow filaments and sheets that together comprise the "cosmic web”. This gas accretion supplies fuel for star formation, sets the angular momentum and size of disk galaxies, and drives turbulence and disk instabilities. We cannot fully understand galaxy evolution without a detailed understanding of this accretion process. However, numerical simulations of this inflow are extremely challenging. This research team will address these shortcomings through an extended suite of cosmological magneto-hydrodynamical simulations designed to resolve the filaments and IGM to accurately model their evolution and explore the detailed physics of how galaxies are fed from their earliest stages of formation. This work will provide mentoring and training for two graduate students. The team will also create a cosmology module for Yale's Pathway to Science program and run a free two-week summer STEM program for high school students. The proposed simulations will resolve the multiphase structure of gas over all the relevant scales, from the Mpc-sized cosmic sheets and filaments to the dense clumps (tens of parsecs) of gas that form within the streams and the stream-fed disks. Such a comprehensive theoretical analysis promises to reshape the understanding of galaxy formation in a cosmological context as well as deepen our understanding of the physics of multiphase plasmas. It is also highly timely to aid in interpreting current and upcoming observational data of the gas around galaxies, Lyman-alpha blobs, the Lyman-alpha Forest, and metal-free Lyman limit systems. In addition, this study aims to improve the understanding of how high-z disk galaxies acquire their angular momentum and which mechanisms are responsible for triggering turbulence and maintaining violent instabilities. All simulations run as part of this study will be made publicly available. The team will also build analytic models that encapsulate their findings and elucidate the physics of galaxy formation.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.