Dark Matter and the Dynamics of Galaxies

在过去的二十年里，天文学家已经积累了大量的证据，证明宇宙中存在一个看不见的组成部分，它施加了类似引力的影响，但没有其他可识别的特征。这种成分被称为“暗物质。“我们对星系中暗物质的含量和分布的不完善的知识是我们目前对星系结构和形成的理解的主要障碍。该项目分为三个部分，旨在测量不同星系的暗物质含量。其中两个研究项目将试图量化螺旋星系中暗物质的数量，第三个项目将寻找有棒星系和无棒星系的暗物质含量之间可能存在的系统差异。这些项目涉及星系模型的计算机数值计算，同时考虑到引力引起的“粒子”运动以及气体冷却并沉降到预先存在的势威尔斯中时暗物质晕的绝热压缩。该计划的最终成果之一是详细阐述了星系中棒的起源机制，最近的观测和理论发展使这一主题变得更加紧迫。该项目的资金由NSF河外天文宇宙学计划（AST/EXC）提供。*

AST-0098282Sellwood, Jerry A.Over the past two decades astronomers have amassed a considerable body of evidence for the existence of an unseen component of the universe which exerts a gravitational-like influence but has no other identified signature. This component is known as "dark matter." Our imperfect knowledge of the content and distribution of dark matter in galaxies is a major obstacle to our current understanding of the structure and formation of galaxies. This project has three parts all of which are designed to measure the dark matter content of different galaxies. Two of these research projects will attempt to quantify the amount of dark matter in spiral galaxies and the third will search for a possible systematic difference between the dark matter content of barred galaxies and of their unbarred counterparts. These projects involve numerical computer computations of galaxy models taking into account both gravitationally induced "particle" motion as well as adiabatic compression of dark matter halos as gas cools and settles into pre-existing potential wells. One final result of this program is the elaboration of a mechanism for the origin of bars in galaxies, a topic which has been given renewed urgency by recent observational and theoretical developments. Funding for this project was provided by the NSF program for Extragalactic Astronomy & Cosmology (AST/EXC).***