The Milky Way's disk in the age of Gaia

我建议研究银河系圆盘的性质，并由此推断我们在宇宙中的家园是如何在宇宙时间内形成和演变的。经过世纪的详细研究，银河系的许多最基本的性质仍然知之甚少。这包括它的质量，这个质量是如何从中心分布到外围的，有多少是暗物质，有多少恒星在不同的时期形成，有什么化学性质，以及什么样的螺旋结构--当我们观察其他星系时很清楚--在银河系中看起来像什么，它对恒星的运动有什么影响。测量大量恒星的距离、运动、年龄和化学丰度的新恒星调查正在进行中，这将极大地扩展研究银河系性质的可用数据。 我将确定银河系大部分圆盘上恒星的空间、运动学和年龄分布，以及这些分布如何取决于化学丰度。这将阐明星星形成的过程，通过不同类型恒星的反馈进行化学富集，并为我们提供一个详细的星盘恒星组成的图片。我还将使用恒星的运动来确定质量的总体分布，通过它对恒星轨道的引力，以及如何将这种质量分为普通物质（恒星和气体）和暗物质。最后，我将研究恒星运动的偏差，从简单的光滑模型的质量分布，以确定螺旋结构的影响，中央酒吧，和其他种类的非轴对称，时间相关的扰动。通过这些研究的结合，这项工作将为星系形成和暗物质的物理学提供重要的新见解。

I propose to investigate the properties of the Milky Way's disk and from this deduce how our home in the Universe formed and evolved over cosmic time. After a century of detailed study, many of the most basic properties of the Milky Way are still poorly understood. This includes its mass, how this mass is distributed from the center to the outskirts and how much of it is dark matter, how many stars are formed at different epochs and with what chemical properties, and what spiral structure---so clear when we look at other galaxies---looks like in the Milky Way and what effect it has on the motions of stars. New stellar surveys that measure the distances, motions, ages, and chemical abundances of large numbers of stars are being conducted now that will vastly expand the available data for investigating the properties of the Milky Way. I will determine the spatial, kinematic, and age distributions of stars over a large part of the Milky Way's disk and how these depend on chemical abundances. This will elucidate the processes of star formation, chemical enrichment through feedback from different kinds of stars, and provide us with a detailed picture of the stellar make-up of the disk. I will also use the motions of stars to determine the overall distribution of mass through its gravitational pull on stellar orbits and how this mass is divided into ordinary (stars and gas) and dark matter. Finally, I will investigate the deviations in the stellar motions from simple smooth models for the mass distribution to determine the influence of spiral structure, the central bar, and other kinds of non-axisymmetryc, time-dependent perturbations. Through the combination of these investigations, this work will provide important new insights into the physics of galaxy formation and dark matter.