Collaborative Research: Searching for Dark Matter Subhalos in Distant Strong Gravitational Lenses

该项目旨在利用爱因斯坦在一个多世纪前首次预测的引力透镜效应，将美国国家科学基金会（NSF）的阿塔卡马大型毫米波/亚毫米波阵列（ALMA）改造成一个强大的暗物质基础物理学和星系形成天体物理学探测器。该项目的主要目标是量化暗物质的特性，暗物质是我们宇宙中神秘的组成部分，它的引力将星系捆绑在一起，但在我们最先进的加速器上的对撞机实验中却无法探测到它。暗物质代表了超越40多年前发展起来的基础物理标准模型的新物理学最令人信服的证据，因此几十年来一直是理论和实验两方面深入研究的主题。该基金支持的研究将被纳入一个将天文学纳入伊利诺伊州五年级课堂的项目，来自代表性不足群体的本科生将在斯坦福大学参与该项目下的研究活动。该研究项目包括一系列理论、数值和观测研究，为将ALMA对透镜尘埃星系的观测转化为对暗物质微物理特性的约束奠定基础。ALMA对引力透镜星系的观测将用于寻找透镜天体质量分布中的子结构。考虑到ALMA数据集的规模和透镜建模的复杂性，需要检测低质量子结构的极其细微的影响，该分析将在像NSF的Blue Waters这样的千万亿次计算设备上进行，使用由调查团队开发的新型分析管道。数值模拟将用于量化各种暗物质模型中预期的子结构的丰度，这些模型探索暗物质的不同物理特性，包括各种自相互作用，温度和康普顿波长，使用由调查团队编写的新型模拟软件。此外，对探测到的暗物质亚晕的叠加光学/红外观测将为最小星系的平均恒星质量-晕质量关系提供迄今为止最严格的界限，这是所有星系形成模型的关键输入。

This project aims to transform the NSF facility ALMA, the Atacama Large Millimeter/submillimeter Array, into a powerful probe of the fundamental physics of dark matter and the astrophysics of galaxy formation, using an effect known as gravitational lensing first predicted by Einstein over a century ago. The main goal of the project is to quantify the properties of dark matter, the mysterious component of our Universe whose gravity binds galaxies together but which has eluded detection in collider experiments at our most advanced accelerators. Dark matter represents the most compelling evidence for new physics beyond the Standard Model of fundamental physics developed over 40 years ago and has therefore been the subject of intensive study, both theoretical and experimental, for many decades. Research supported by this grant will be incorporated into a program for integrating astronomy into 5th grade classrooms in Illinois, and undergraduates from underrepresented groups will participate in research activities under this project at Stanford.The research program involves a suite of theoretical, numerical, and observational research to lay the groundwork needed to translate ALMA observations of lensed dusty galaxies into constraints on the microphysical properties of dark matter. ALMA observations of gravitationally lensed galaxies will be used to search for substructure in the mass distributions of the lensing objects. Given the scale of ALMA data sets and the complexity of the lens modeling required to detect extremely subtle effects of low-mass substructure, this analysis will be performed on petascale computing facilities like NSF's Blue Waters using a novel analysis pipeline developed by the investigating team. Numerical simulations will be used to quantify the abundance of substructure expected in a variety of dark matter models that explore different physical characteristics of dark matter including various self-interactions, temperatures, and Compton wavelengths, using novel simulation software written by the investigating team. In addition, stacked optical/IR observations of detected dark matter subhalos will provide the most stringent bounds to date on the mean stellar mass - halo mass relation in the smallest galaxies, a crucial input for all models of galaxy formation.