Charting the Structure of the Milky Way Stellar Halo and Disk

研究人员试图了解我们的银河系。银河系的轨道上有几十个较小的矮星系。这些矮小星系正被我们的星系引力撕裂成长长的恒星流。其中一些小溪环绕着整个银河系。这位研究人员最近发现，包括螺旋结构在内的银河系圆盘上存在着此前不为人知的“涟漪”。这些涟漪被认为是在较小的矮星系落入银河系时形成的，就像落入池塘的鹅卵石在水面上产生涟漪一样。通过绘制整个银河系的恒星密度图，这个项目建立了银河系和围绕它运行的矮小星系之间相互作用的模型。这些模型将帮助我们了解暗物质的位置。这些模型还告诉我们星系的旋臂是如何形成和维持的。这个项目将培养本科生的科学和计算能力。调查员将通过持续的公众宣传倡议，让公众参与科学进程。公众活动将包括科学网页、Facebook、Twitter、Instagram、YouTube视频、Reddit Ask Me Anything(AMA)会议、通过小型望远镜观察天空的机会，以及将覆盖数千名儿童、青少年、成年人和老年人的动手扩展活动。在任何给定的时间，研究人员将与大约20,000人保持联系，他们自愿使用个人计算机创建MilkyWay@home超级计算机。调查人员将使用斯隆数字天空调查的主序列和星系光晕中的关闭恒星绘制我们银河系盘状和光晕中的三维恒星密度图。研究人员将使用统计光度视差技术来制作密度图。这项技术不需要测量到每一颗恒星的距离，就可以恢复底层的密度分布，因为只需要固有的亮度分布。外盘和恒星晕将被绘制成关闭恒星的地图。主序星本质上较暗，将被用来追踪银河系盘中较近恒星的密度。研究人员将绘制主要的子结构图，包括恒星中面的垂直振荡。

The investigator seeks to understand our Milky Way galaxy. The Milky Way has dozens of smaller dwarf galaxies in orbit around it. These dwarf galaxies are being ripped apart by our galaxy's gravity into long streams of stars. Some of these streams encircle the entire galaxy. The investigator recently discovered that the disk of the Milky Way, which includes the spiral structure, has previously unknown 'ripples'. These ripples are believed to form when smaller dwarf galaxies fall into the Milky Way, just as a pebble dropped into a pond produces ripples on the surface of the water. By mapping the density of stars throughout the Milky Way, this project model of the interaction between the Milky Way galaxy and the dwarf galaxies orbiting it. These models will help us understand where dark matter is located. The models also teach us how the spiral arms of galaxies are made and sustained. This project will train undergraduate students in science and computing. The investigator will engage the public in the scientific process through sustained public outreach initiatives. Public outreach will include science web pages, Facebook, Twitter, Instagram, YouTube videos, Reddit Ask Me Anything (AMA) sessions, opportunities to observe the sky through small telescopes, and hands-on outreach activities that will reach thousands of children, teens, adults, and seniors. A relationship will be maintained between the investigators and the ~20,000 people, at any given time, who volunteer their personal computers to create the MilkyWay@home supercomputer.The investigator will map the three dimensional stellar density in the disk and halo of our galaxy, using Sloan Digital Sky Survey main sequence and turnoff stars in the galaxy's halo. The investigator will use the technique of statistical photometric parallax to make the density maps. This technique recovers the underlying density distribution without measuring the distance to each individual star, because only the intrinsic brightness distribution is required.The outer disk and the stellar halo will be mapped with turnoff stars. Main sequence stars, which are intrinsically dimmer, will be used to trace the density of closer stars in the Milky Way disk. The investigator will map the dominant substructures, including the vertical oscillations of the stellar mid-plane.