LEAPS-MPS: The tiniest galaxies in the Universe as testbeds of fundamental physics

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公法117-2)。关于宇宙的一个悬而未决的基本问题是，物质中不与光相互作用的冷暗物质的比例。这一部分被称为Lambda_CDM，在标准宇宙学模型中控制着星系的形成和演化。虽然该模型对银河系等较大的星系非常有效，但对于较小的星系，如矮星系，也存在挑战。这个项目将雇用西班牙裔服务机构的本科生进行尖端的宇宙学研究，使用最新的模型来探索关于我们宇宙的基本问题，比如“暗物质的本质是什么？”学生们将把这些模型应用于低质量星系，以做出预测，这些预测将在未来的观测中得到验证。学生将通过加州桥计划招收，该计划侧重于来自代表性不足背景的学生。学生们将利用对超暗矮星系的观测来约束围绕较大星系形成的矮星系的宇宙学模型。他们将根据给定的输入参数，如Lambda_CDM，对银河系大小的星系周围的矮小星系数量进行可测试的预测，这将对宇宙中冷暗物质的数量施加限制。他们还将限制宇宙电离背景的来源和时间，预测矮小星系的主要合并对恒星运动学的影响，并测试银河系大小的星系的存在对这些实验结果的影响。这一奖项反映了美国国家科学基金会的法定使命，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。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). One of the open fundamental questions about the universe is the fraction of matter that is ‘cold dark matter,’ which does not interact with light. This fraction, called LAMBDA_CDM, governs how galaxies form and evolve in the standard cosmological model. While the model works very well for larger galaxies like the Milky Way, there are challenges for smaller galaxies, such as dwarf galaxies. This project will employ undergraduate students at a Hispanic Serving Institution in cutting-edge cosmological research using the latest models to explore fundamental questions about our universe, such as ‘what is the nature of dark matter?’ The students will apply these models to low-mass galaxies to make predictions that will be testable with future observations. Students will be recruited through the Cal-Bridge Program, which focuses on students from under-represented backgrounds. Students will use observations of ultra-faint dwarf galaxies to constrain cosmological models of dwarf galaxy formation around larger galaxies. They will produce testable predictions of the number of dwarf galaxies around a Milky Way-size galaxy for given input parameters such as LAMBDA_CDM, which will place constraints on the amount of cold dark matter in the Universe. They will also place limits on the sources and timing of the cosmic reionizing background, make predictions for the effect of dwarf galaxy major mergers on stellar kinematics, and test the effect of the presence of a Milky Way-size galaxy on the results of these same experiments.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.