Collaborative Research: The Destruction and Growth of Halo Clouds

为了使星系形成新的恒星，星系会聚集更多的氢气。这种气体被认为像雨点一样落在星系上，事实上，在银河系周围已经发现了不同形状和大小的气体云。因为我们看到的是一个单一的快照，所以这些气体云的命运实际上是未知的。这个项目将确定氢云是否会在它们落入星系时作为恒星形成的燃料而增长，或者云是否会在它们下落时被分散和破坏。研究人员将把云向星系移动的计算机模拟与对银河系附近云的新观测进行比较。学生们将接受如何进行科学研究的培训，观察结果将与公众分享。热介质中冷气体云的破坏和生长背后的物理过程是一个长期存在的天体物理学问题。对于最近的理论进展来说，一个理想的试验场是在我们自己的银河系中，特别是在我们银河系的光晕中，在那里可以很容易地分离出离散的云，在很大程度上与恒星形成的过程分开，并且可以很好地观察到。在观测面上，将对新的高分辨率晕云观测结果与高保真的云破坏和增长的磁流体动力学模拟进行详细的比较。为了完成模拟与观测的对比，将建立一个不同物理条件下的模拟云库，并准备一套有距离约束的云观测数据。模拟云将被放置在观测平面上比较空间形态和速度结构。除了为学生提供研究经验外，该项目还将开发一门科学服务学习课程，教本科生更好地向当地社区解释科学研究的方法。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In order for a galaxy to form new stars, the galaxy gathers more hydrogen gas. This gas is thought to rain down onto the galaxy, and indeed, gas clouds of different shapes and sizes are already found around the Milky Way galaxy. Because we see a single snapshot in time, the fate of these gas clouds is not actually known. This project will determine whether the hydrogen clouds grow as they fall into the galaxy as star formation fuel, or if the clouds will be scattered and destroyed as they fall. The investigators will compare computer simulations of clouds moving towards a galaxy to new observations of clouds near the Milky Way. Students will be trained how to conduct scientific research, and the observations will be shared with the public. The physical processes behind the destruction and growth of cool gas clouds in a hot medium is a long standing astrophysical problem. An ideal testing ground for recent theoretical advances is in our own Milky Way, in particular in the halo of our Galaxy, where discrete clouds can be easily isolated, are largely separate from the process of star formation, and are well observed. Detailed comparisons will be made, in the observational plane, of new high-resolution observations of halo clouds to high-fidelity magnetohydrodynamic simulations of the cloud destruction and growth. To complete the comparison between the simulations and observations, a library of simulated clouds with varying physical conditions will be created, and a suite of observational data on clouds with distance constraints will be prepared. The simulated clouds will be put onto the observational plane to compare the spatial morphologies and velocity structures. In addition to the research experiences for students, the project will develop a science service learning course that will teach undergraduates better methods for explaining scientific research to the local community.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.