Collaborative Research: Shedding Light on the Complex and Covariant Properties of Massive Halos with Theory and Observations

要了解暗物质的本质，最有希望的地方是它形成的密度最大的物体，也就是所谓的“光晕”。然而，由于暗物质是看不见的，因此即使是推断光晕最简单的性质，比如它们的总质量，也是一项挑战。我们知道各种可观测到的指标（不完全）与质量相关，包括光晕中星系的恒星，光晕周围的光线弯曲，以及早期宇宙背景光上的气体印记。难点在于将这些指标的信息结合起来，因为不同类型的观测通常针对天空的不同部分。有了新的，重叠的调查，我们现在可以结合不同的观测到的相同的光晕。这是马里兰大学帕克分校和加州大学圣克鲁斯分校的科学家之间的观察者-理论家合作，将基于一些最大的超级计算机模拟晕和星系的形成以及快速机器学习技术，开发一个框架来解释组合的观测结果。该团队将把这个框架应用到他们可以访问的调查数据的独特组合中。该项目还将通过新成立的种子勺科学项目支持加州大学圣克鲁斯分校的拉丁裔STEM学生，该项目依靠种植和烹饪食物的文化实践来创建一个长期的指导社区。星团晕的质量和密度结构包含了丰富的宇宙学和物理信息，但它们必须从不完善的观测示踪剂中推断出来，比如来自中心和卫星星系的恒星，来自气体的Sunayev-Zel 'dovich （SZ）信号，以及弱透镜效应。如今，大规模重叠巡天的新时代使得对同一星团光晕进行多波长观测成为可能，但要做到这一点，我们需要了解它们复杂的协方差。该项目建议开发一个理论和实践框架，用于解释基于一些最大的结构形成模拟，灵活的物理模型和快速机器学习技术的全色观测。然后，研究小组将把这个框架应用到重叠的暗能量光谱仪器（DESI）、阿塔卡马宇宙学望远镜（ACT）、暗能量相机遗留调查（DECaLS）和超级超级相机（HSC）足迹上，以便在观测上限制星系团暗物质晕特性的协方差。该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知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The most promising place to learn about the nature of dark matter is in the densest objects it forms, which are called "halos." As dark matter is invisible, however, it is challenging to infer even the simplest properties of halos, such as their total mass. We know of various observable indicators that (imperfectly) correlate with mass, including the stars of the galaxies in a halo, the bending of light around it, and the imprint of gas on background light from the early Universe. The difficulty has been to combine the information from these indicators because the different types of observations were typically available for different parts of the sky. With new, overlapping surveys, we can now combine different observables for the same halos. This observer-theorist collaboration between scientists at the University of Maryland, College Park and the University of California, Santa Cruz, will develop a framework to interpret combined observables based on some of the largest supercomputer simulations of the formation of halos and galaxies and on fast machine learning techniques. The team will apply this framework to a unique combination of survey data that they have access to. This project will also support Latinx STEM students at UC Santa Cruz via the newly created Seed Spoon Science program, which relies on the cultural practices of growing and cooking food to create a long-term mentoring community.The mass and density structure of cluster halos contain a wealth of cosmological and physical information, but they must be inferred from imperfect observational tracers such as the stars from central and satellite galaxies, the Sunayev-Zel’dovich (SZ) signal from gas, and weak lensing. The new era of large, overlapping sky surveys now makes it possible to combine multi-wavelength observables for the same cluster halos, but to do so we need to understand their complex covariances. This project proposes to develop a theoretical and practical framework for interpreting panchromatic observations based on some of the largest simulations of structure formation, on flexible physical models, and on fast machine learning techniques. The team will then apply this framework to the overlapping Dark Energy Spectroscopic Instrument (DESI), Atacama Cosmology Telescope (ACT), Dark Energy Camera Legacy Survey (DECaLS), and Hyper Suprime-Cam (HSC) footprints in order to observationally constrain the covariance of dark matter halo properties for galaxy clusters.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.