Collaborative Research: Distances to High-Velocity Clouds

这项合作奖将资助一个项目的继续，以测量银河系高速云（HVC）的距离，大量的中性氢气云以与银河系旋转微分的简单模型不兼容的速度移动。由于它们从银河系盘中的气体中脱颖而出，它们可以用作银河系中高能现象的测试粒子。 该计划将使用投射到云层上的恒星光谱中的星际吸收线来研究HVC金属丰度和距离。这个项目的结果将是重要的几个基本参数的银河系演化的估计，包括低金属含量气体的下降率，暗物质晕的潜力，气体之间的循环速度盘和晕，和电离光子逃离磁盘的分数。更广泛的影响这个计划包括研究生和本科生的培训。

This collaborative award will fund continuation of a project to measure distances to the Galactic high velocity clouds (HVCs), massive clouds of neutral hydrogen gas moving at velocities incompatible with a simple model of differential galactic rotation. Since they stand out from the gas in the Galactic Disk, they can be used as test particles for energetic phenomena in the Milky Way. The program will study HVC metallicities and distances using interstellar absorption lines in the spectra of stars projected against the clouds. The results of this project will be important for estimates of several fundamental parameters of Galactic evolution, including the rate of infall of low metallicity gas, the potential of the dark matter halo, the rate of circulation of gas between Disk and Halo, and the fraction of ionizing photons escaping the Disk.The Broader Impacts of this program include training of graduate and undergraduate students.