The Dynamical Echoes Of Dark Matter Sub-Structure: In Simulations & In Spirals Out To z ~ 0.1

目前的宇宙学范式包括两个重要的和未知的物理实体，即“暗物质”和“暗能量”，它们被用来对我们所知的宇宙进行建模。了解暗物质的分布仍然是天文学中最基本的问题之一，也是这个项目的重点。现有的计算机模拟中的暗物质子结构与观测中的暗物质子结构之间存在着许多差异。与模拟相比，大质量的卫星太少了，在银河系的低纬度地区，几乎没有任何银河系卫星。该项目旨在通过研究人员正在进行的通过分析扩展的氢气盘中的扰动来表征银河卫星的工作，提取关于螺旋星系中暗物质分布的基本信息。向广大受众交流科学成果，促进多样性，使天文学界和整个社会受益。该项目将在罗切斯特理工学院(RIT)进行，该学院历史上主要是一个本科生机构：(1)科学领域的妇女：国际科学联合会将与来访的妇女座谈会演讲者定期举行会议，目的是收集关于专业发展的建议。查克拉巴蒂博士还将继续参与扩展你的视野计划，该计划旨在吸引中学女生参与科学。(2)计算训练营：每年夏天，国际计算训练营将提供为期两周的密集计算训练营，面向研究生入学。这个训练营的目标是作为一座桥梁-提供计算天体物理学的入门课程，并提供说明计算基础知识和天文学应用的动手课程。视觉化实验室：视觉化实验室：视觉化实验室将继续制作星系碰撞的3-D动画，并将在RIT的Viz-Lab展示。3-D电影是一种越来越受欢迎的公众工具，也是广泛传播星系演化研究的有效工具。PI将执行以下技术任务：(1)银河系：通过将模拟的银河系卫星轨道与HST自行和潮汐碎片进行匹配，PI将推导出对轨道参数以及银河系卫星初始恒星(和暗物质)分布的约束。PI将产生与HI和我们星系的恒星数据相一致的模型，该星系显示出外围的大涟漪、突出的翘曲和银盘中的垂直波。(2)探测暗物质晕：暗物质晕作为时间的函数演变，它们可能具有复杂的形状。PI将决定从恒星流中推断晕势对于时变势是否可行。通过解构流体动力学宇宙模拟ERIS，PI将研究卫星的分布以及气体和星盘的形态是否代表银河系或局部螺旋。(3)局部螺旋的抖动和嘎嘎：通过模拟来自宇宙模拟的大范围与子晕的相遇，并使用蒙特卡洛马尔科夫链分析以统计稳健的方式映射到多个观测约束，PI将产生真实的HI盘及其卫星群的模拟星表和演化史。(4)HI中的强螺旋透镜：由于Swells样本是一个足够低红移的强螺旋透镜样本(z_avg~0.1)，显示出可见的相互作用迹象，PI将比较和对比团队的HI分析和引力透镜，以得出关于暗物质分布的两个独立约束。

The current cosmological paradigm includes two significant and unknown physical entities called "dark matter" and "dark energy," which are used to model the Universe as we know it. Understanding the distribution of dark matter remains one of the most fundamental problems in astronomy and is the focus of this project. There are many discrepancies between dark matter sub-structure in the existing computer simulations and in observations. There are too few massive satellites relative to simulations, and at low Galactic latitudes there are hardly any Milky Way satellites. This project aims to extract essential information on the dark matter distribution in spiral galaxies by building on the investigator's ongoing work in characterizing galactic satellites from analysis of disturbances in extended disks of hydrogen gas.Communicating scientific results to a broad audience and promoting diversity benefits the astronomy community and our society at large. This project will be carried out at Rochester Institute of Technology (RIT), which has historically been primarily an undergraduate institution:(1) Women in Science: The PI will organize regular meetings with visiting women colloquium speakers, with the goal of gathering advice on professional development. Dr. Chakrabarti will also continue participating in the Expanding Your Horizons program, which is geared towards engaging middle school girls in science.(2) Computational Bootcamp: Every summer, the PI will provide a two-week, intensive computational bootcamp geared towards entering graduate students. The goal of this bootcamp is to serve as a bridge---providing an introduction to computational astrophysics, with hands-on lectures that illustrate the basics of computing and applications to astronomy. The PI will work through simple examples in IDL and Python, and she will encourage women and minority students to attend the bootcamp, and assign mentors for entering students.(3) Visualization Laboratory: The PI will continue producing 3-D animations of galaxy collisions, which will be showcased in the Viz-Lab at RIT. Three-D movies are becoming an increasingly popular tool to engage the public and are effective in widely disseminating research on galaxy evolution.The PI will carry out the following technical tasks:(1) The Milky Way: By matching simulated orbits of the Milky Way satellites with HST proper motions and tidal debris, the PI will derive constraints on the orbital parameters, as well as the initial stellar (and dark matter) distribution of the Milky Way satellites. The PI will produce models that are consistent with both the HI and stellar data of our galaxy, which displays large ripples in the outskirts, a prominent warp, and vertical waves in the galactic disk.(2) Probing The Dark Matter Halo: Dark matter halos evolve as a function of time, and they may have complex shapes. The PI will determine if the inference of the halo potential from stellar streams is viable for time-varying potentials. By deconstructing the hydrodynamical cosmological simulation ERIS, the PI will study if the distribution of satellites and the morphology of the gas and stellar disk is representative of the Milky Way or local spirals.(3) Shaking and Rattling The Local Spirals: By simulating a wide range of encounters with sub-halos from cosmological simulations, and mapping to multiple observational constraints in a statistically robust manner using a Monte Carlo Markov Chain analysis, the PI will produce realistic mock catalogs and evolutionary histories of HI disks and their satellite populations.(4) Strong Spiral Lenses in HI: As the SWELLS sample is a sufficiently low redshift sample of strong spiral lenses (z_avg ~ 0.1) showing visible signs of interaction, the PI will compare and contrast the team's HI analysis and gravitational lensing to derive two independent constraints on the dark matter distribution.