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

在过去的二十年里，星系形成的连贯图像已经出现，气体从星系际介质（IGM）通过狭窄的细丝和薄片网络流入大质量暗物质晕，这些细丝和薄片共同组成了“宇宙网”。这种气体吸积为星星的形成提供了燃料，设定了盘星系的角动量和大小，并驱动了湍流和盘的不稳定性。如果不详细了解这个吸积过程，我们就无法完全理解星系的演化。然而，这种流入的数值模拟极具挑战性。该研究小组将通过一套扩展的宇宙学磁流体动力学模拟来解决这些缺点，该模拟旨在解决细丝和IGM，以准确地模拟它们的演化，并探索星系如何从其形成的最早阶段开始喂养的详细物理学。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。所提出的模拟将解决所有相关尺度上的气体多相结构，从Mpc大小的宇宙片和细丝到在流和流馈盘内形成的致密气体团（数十秒差距）。这样一个全面的理论分析有望重塑宇宙学背景下的星系形成的理解，以及加深我们对多相等离子体物理的理解。这也是非常及时的，以帮助解释当前和即将到来的观测数据的气体周围的星系，莱曼α斑点，莱曼α森林，和无金属莱曼限制系统。此外，这项研究旨在提高对高z盘星系如何获得角动量的理解，以及哪些机制负责触发湍流和维持剧烈的不稳定性。作为本研究一部分运行的所有模拟将公开提供。该团队还将建立分析模型，以封装他们的发现并阐明星系形成的物理学。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

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.