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

该项目旨在将美国国家科学基金会的ALMA(阿塔卡马大毫米/亚毫米阵列)改造成一个强大的探测器，利用爱因斯坦一个多世纪前首次预测的引力透镜效应，研究暗物质的基本物理和星系形成的天体物理。该项目的主要目标是量化暗物质的性质，暗物质是我们宇宙中的神秘组成部分，它的引力将星系捆绑在一起，但在我们最先进的加速器的对撞机实验中，它未能被发现。暗物质代表了40多年前发展起来的基础物理标准模型之外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深入研究的主题。这笔资金支持的研究将被纳入伊利诺伊州一项将天文学融入五年级课堂的计划，来自代表性不足群体的本科生将参加斯坦福大学这一项目的研究活动。研究计划包括一系列理论、数值和观测研究，以奠定必要的基础，将ALMA对透镜状尘埃星系的观测转化为对暗物质微观物理性质的限制。对引力透镜星系的ALMA观测将被用来在透镜天体的质量分布中寻找亚结构。考虑到ALMA数据集的规模和检测低质量子结构极其微妙的影响所需的透镜建模的复杂性，这种分析将在像NSF的Blue Waters这样的千万亿级计算设施上使用调查团队开发的新型分析管道进行。数值模拟将被用来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征，包括各种自相互作用、温度和康普顿波长，使用调查小组编写的新型模拟软件。此外，对探测到的暗物质亚晕的光学/红外叠加观测将为最小星系的平均恒星质量-晕质量关系提供迄今最严格的界限，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.