Collaborative Research: Connecting the Smallest and the Largest Galaxies to their Dark Matter Halos

天文学家试图了解星系是如何形成和演化的。星系中的发光物质，如我们自己的星系(银河系)，存在于更广泛的暗物质光晕中。尽管暗物质的性质尚不清楚，但其引力效应是可以研究的。天文学家使用模拟来预测暗物质晕如何演化。他们使用间接的方法来推断它在被观测的星系中的存在。然而，这些暗物质晕和它们的宿主星系之间的关系仍然不确定。对于最低质量的星系和最高质量的星系，我们的理解是最弱的。Leauthaud和他的合作者将在这一创新的观测研究计划中探索这两个极端。使用一种新的高分辨率成像测量，他们将测量数万个星系的暗物质晕。他们将把暗物质与发光物质的轮廓进行比较。他们将专注于最需要观测的矮星系和巨星系。这项研究将为暗物质和发光物质之间的关系带来新的见解。这项提案的延伸将包括为本科生提供统计和计算方法的暑期培训，作为普林斯顿大学和加州大学圣克鲁斯分校既定项目的一部分。普林斯顿计划将与国家天文学联盟合作，从少数族裔和服务不足的人群中招收学生。加州大学圣克鲁斯分校的项目将通过哈特内尔学院(Hartnell College)招生，哈特内尔学院是邻近的一所拉美裔服务机构。这些活动一起将扩大历史上代表性不足的群体对科学的参与。这个项目将促进我们对描述星系中普通物质和暗物质之间关系的恒星质量-晕质量关系的理解。对暗物质的间接探测将通过使用位于莫纳克亚的斯巴鲁8.2米望远镜上的Hyper SuPrime-Cam(HSC)调查数据的微弱透镜来实现。该项目将推进这种弱透镜测量的最新技术。此外，由于这次调查的面积很大，HSC将探测位于最大暗物质晕中心的罕见和极大质量的星系(10^11.5毫升)。该项目将识别数万个这样的大质量星系，并对它们进行弱透镜测量。它还将通过弱透镜研究大量的矮星系(10^9mSun)。这些研究将共同揭示低质量和高质量星系的发光物质和暗物质之间的关系。正是在质量范围的这些极端情况下，最需要新的测量来解决与理论模型的差异。

Astronomers seek to understand how galaxies form and evolve. The luminous matter in galaxies such as our own galaxy (the Milky Way) resides within more extensive halos of dark matter. Although the nature of dark matter is still unknown, its effects due to gravity can be studied. Astronomers use simulations to predict how dark matter halos evolve. They use indirect means to infer its presence among observed galaxies. However, the relationship between these dark matter halos and their host galaxies is still uncertain. Our understanding is weakest for the very lowest mass galaxies and for the highest mass galaxies. Leauthaud and collaborators will explore both extremes in this innovative observational research program. Using a new, high resolution imaging survey, they will measure the dark matter halos for tens of thousands of galaxies. They will compare dark matter to the profiles of luminous matter. They will focus on dwarf galaxies and giant galaxies where observations are most needed. This research will lead to new insights into the relationship between dark matter and luminous matter. Outreach from this proposal will include summer training in statistical and computational methods for undergraduates as part of established programs at Princeton and UC-Santa Cruz. The Princeton program will work with the National Astronomy Consortium to recruit students from minority and underserved populations. The UC-Santa Cruz program will recruit students through Hartnell College, a neighboring Hispanic serving institution. Together these activities will broaden participation in science among historically underrepresented groups.This project will advance our understanding of the stellar mass-halo mass relation that describes the relationship between ordinary matter and dark matter in galaxies. Indirect detection of dark matter will be made via weak lensing using data from the Hyper Suprime-Cam (HSC) survey on the Subaru 8.2-m telescope at Mauna Kea. This project will advance the state-of-the-art for such weak lensing measurements. In addition, due to the large area of this survey, HSC will detect rare and extremely massive galaxies ( 10^11.5 Msun) that lie at the heart of the largest dark matter halos. This project will identify tens of thousands of such massive galaxies and perform weak lensing measurements on them. It will also study large numbers of dwarf galaxies ( 10^9 Msun) via weak lensing. Together these studies will reveal the relationship between luminous matter and dark matter for both low and high mass galaxies. It is in these extremes of the mass range where new measurements are most needed to resolve discrepancies with theoretical models.