Bright Field Galaxies and their Dark Matter Halos

尽管人们普遍认为大质量的暗物质晕围绕着所有大而明亮的星系，但星系大小的暗物质晕的许多基本性质仍然很不清楚。这个项目的重点是利用小的、微弱的卫星星系，在大的、明亮的星系的引力势内运行，以获得对当前光晕限制的实质性改进。该研究将结合理论、档案和新观测，以及数值数据集，来解决a)最好的光晕病毒质量估计器，b)如何最好地测量卫星星系的速度色散，c)质量光比对光度的依赖，以及这是否在早型和晚型星系中有所不同，d)晚型星系的光晕是否与早型星系的光晕根本不同。e)盘状星系的角动量与其光晕的净角动量是否密切相关。首席研究员将参加洛厄尔天文台成功的外展计划，目标是纳瓦霍和霍皮民族学校的五年级到八年级学生。这种教师与天文学家的合作关系是一个重要的时间承诺，包括课堂访问，时间安排在观测运行的同时，以及对学生的长期实地考察。这项研究将有助于研究生的专业发展。所有真实的和模拟的数据，以及使用的软件，都将是公开的。

AST-0708468BrainerdAlthough it is generally accepted that massive dark matter halos surround all large, bright galaxies, many of the basic properties of galaxy-sized dark matter halos remain poorly constrained. This project focuses on using small, faint satellite galaxies, orbiting within the gravitational potentials of large, bright field galaxies, to obtain a substantial improvement over the current halo constraints. The research will use a combination of theory, archival and new observations, and numerical datasets, to address a) the best halo virial mass estimator, b) how best to measure the velocity dispersion of satellite galaxies, c) the dependence of the mass-to-light ratio on luminosity, and whether this differs for early- and late-type galaxies, d) whether the halos of late-type galaxies are fundamentally different from those of early-type galaxies, and e) whether the angular momentum of a disk galaxy closely correlates with the net angular momentum of its halo.The principal investigator will participate in Lowell Observatory's successful outreach program, targeting fifth through eighth grade students at Navajo and Hopi Nation Schools. This teacher-astronomer partnership is a significant commitment of time, including classroom visits, timed to coincide with observing runs, and an extended field trip for the students. The research will contribute to the professional development of a graduate student. All of the genuine and simulated data, and the software used, will be publicly available.