Testing the Cold Dark Matter Model by Constraining Dark Matter Substructure in Gravitational Lens Galaxies

宇宙中的大部分物质都是以暗物质的形式存在的，我们只能通过它的引力来观察它的存在。所有的星系似乎都被巨大的暗物质晕包围着。暗物质支配着星系和星系团的引力场。暗物质是暗的，因为它不发射或吸收光，因此很难研究。事实上，天文学家还不知道暗物质的真正性质。但理解这一点将促进我们对物理基本定律的理解。通过研究星系的暗物质光晕，以及它们的引力如何弯曲来自更远的光源（引力透镜）的光，天文学家可以了解光晕中暗物质的结构——它们是如何形成的。人们开发了各种模型来解释这些现象，它们都可以根据暗物质晕中实际发生的情况进行测试。这项提议的研究将使用重力透镜的高分辨率图像来了解更多关于暗物质晕的结构。这些结果也将有助于确定暗物质粒子的类型。PI的机构为来自弱势群体和/或贫困背景的学生提供服务。该项目的更广泛影响部分将奖励有前途的本科科学和工程专业（至少六名学生在三年内）做研究的津贴（使他们专注于学习和研究，而不是在校外兼职工作）。本科生将学习技能，获得对STEM领域至关重要的经验，同时也为本项目产生有价值的成果。每年夏天，被录取的学生将在美国自然历史博物馆（AMNH）工作。他们将参加一个为期三天的研讨会，以获得科学计算技能，参加每周的会议，讨论天体物理学的最新论文，并在夏末在AMNH“物理科学REU研讨会”上发表他们的研究报告。最后，在接下来的秋季学期之后，学生们将有机会参加美国天文学会（AAS）冬季会议，并以海报展示他们的研究成果。这个项目显然与美国国家科学基金会促进科学进步的使命有关。此外，该项目的“更广泛的影响”部分做到了这一点，并通过帮助培养对下一代不同个人的STEM活动的兴趣和教育来促进国家的健康、繁荣和福利。星系中存在小型暗物质子结构是暗物质理论的一个关键预测，而暗物质理论在很大程度上仍未得到验证。该项目的目标是通过分析高分辨率观测到的引力透镜样本来测试冷暗物质（CDM）范式。拟议的项目将评估在引力透镜星系中探测和表征子结构的方法。特别地，它将由亚毫米电磁光谱范围内的观测透镜组成。在这个地区，带引力透镜的星系正在迅速被发现。通过对这些星系的高分辨率观测（例如通过ALMA望远镜阵列），PI和团队将获得星系中暗物质分布的前所未有的信息。由于引力透镜直接展示了暗物质对时空的扭曲，对引力透镜系统的研究是一种很有前途的方法，可以约束暗物质的一般粒子特性（独立于特定的粒子模型）。该团队的主要目标是展示如何使用这些信息来约束暗物质子结构的详细属性，作为识别暗物质本身性质的一种方式。

Most of the matter in the Universe is in the form of dark matter, whose presence we only observe through its gravity. All galaxies appear to be surrounded by large halos of dark matter. And dark matter dominates the gravitational field of galaxies and clusters of galaxies. Dark matter is dark because it does not emit or absorb light making it hard to study. In fact, astronomers do not yet know the true nature of dark matter. But understanding this will advance our understanding of the fundamental laws of physics.By studying the dark matter halos of galaxies, and how their gravity bends light from more distant sources (gravity lenses), astronomers can learn about the structure of the dark matter in the halos how they were formed. Various models to explain these things have been developed, and they can all be tested based on what actually happens in dark matter halos. This proposed study will use high-resolution images of gravity lenses to learn more about the structure of the dark-matter halos. The results will also help determine the type of particle dark matter is.The PI's institution serves students from underrepresented and/or underprivileged backgrounds. The Broader Impact part of this project will be to award promising undergraduate science and engineering majors (a minimum of six students over three years) a stipend to do research (allowing them to focus on studies and research rather than work part time jobs outside of school). The undergraduates will learn skills, and gain experiences, that are vital to STEM fields, while also producing valuable results for this project. Each year, students accepted to the program will work at the American Museum of Natural History (AMNH) during the summer. They will participate in a three-day workshop to acquire scientific computing skills, attend weekly meetings to discuss recent papers in astrophysics, and at the end of the summer will give a talk on their research at the AMNH "Physical Sciences REU Symposium". Finally, after the following fall semester the students will have the opportunity to attend and give a poster presentation of their research at the winter American Astronomical Society (AAS) meeting.This project clearly relates to NSF's mission to promote the progress of science. In addition, the "Broader Impact" portion of the project does this, and advances the national health, prosperity and welfare by helping to develop interest in, and educating, STEM activities among the next generation of diverse individuals.The existence of small dark matter substructure in galaxies is a key prediction of dark matter theories that remains largely untested. The project's goals are to test the Cold Dark Matter (CDM) paradigm by analyzing a sample of gravitational lenses observed at high resolution. The proposed project will evaluate methods to detect and characterize substructure in gravitational lens galaxies. In particular it will consist of observing lenses in the submillimeter electromagnetic spectral range. Galaxies with gravitational lenses are being discovered rapidly in this area. Using high-resolution observations (e.g. by the ALMA telescope array) of these galaxies, the PI and team will obtain unprecedented information on the dark matter distribution in galaxies. And because gravitational lensing directly exhibits the warping of space time by dark matter, a study of gravitational lens systems is a promising method to constrain generic particle properties of dark matter (independent of specific particle models). The team's primary goal is to show how this information can be used to constrain the detailed properties of dark matter substructure as a way of identifying the nature of dark matter itself.