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。 像我们银河系这样的星系中的发光物质存在于更广泛的暗物质晕中。 虽然暗物质的性质仍然是未知的，但它的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的演变。 他们使用间接的方法来推断它在观测到的星系中的存在。 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。 我们对最低质量星系和最高质量星系的了解是最薄弱的。 Leauthaud和合作者将在这个创新的观察研究项目中探索两个极端。 使用一种新的高分辨率成像调查，他们将测量数万个星系的暗物质晕。 他们将比较暗物质和发光物质的轮廓。 他们将专注于最需要观测的矮星系和巨星系。 这项研究将导致对暗物质和发光物质之间关系的新见解。 这项提议的推广将包括为本科生提供统计和计算方法的夏季培训，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，从少数民族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邻近的西班牙裔服务机构哈特内尔学院招收学生。 这些活动将扩大历史上未被充分代表的群体对科学的参与。该项目将促进我们对恒星质量-晕质量关系的理解，该关系描述了星系中普通物质和暗物质之间的关系。 暗物质的间接探测将通过使用位于莫纳克亚山的斯巴鲁8.2米望远镜上的超超级凸轮（HSC）调查数据的弱透镜进行。 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将探测到位于最大暗物质晕中心的稀有和超大质量星系（10^11.5 Msun）。 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（10^9 Msun）。 这些研究将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。 正是在这些质量范围的极端情况下，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.