Collaborative Research: The Destruction and Growth of Halo Clouds

为了让一个星系形成新的恒星，这个星系聚集了更多的氢气。这种气体被认为像雨点一样落到银河系上，事实上，银河系周围已经发现了不同形状和大小的气体云。因为我们只看到了时间上的一张快照，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在作为恒星形成燃料坠入银河系时增长，还是在坠落时被分散和摧毁。研究人员将比较计算机模拟的向银河系移动的云层与对银河系附近云层的新观测。学生将接受如何进行科学研究的培训，观察结果将与公众分享。热介质中冷气云破坏和增长背后的物理过程是一个长期存在的天体物理问题。最近理论进展的理想试验场是在我们自己的银河系，特别是在我们银河系的光晕中，在那里离散的云可以很容易地分离出来，很大程度上与恒星形成过程分开，并且很好地被观测到。将在观测平面上对新的高分辨率晕云观测与高保真磁流体力学云层破坏和增长模拟进行详细的比较。为了完成模拟和观测之间的比较，将创建一个不同物理条件的模拟云库，并准备一套关于距离限制的云的观测数据。模拟的云层将被放到观测平面上，以比较空间形态和速度结构。除了学生的研究经验，该项目还将开发一门科学服务学习课程，向本科生传授更好的方法向当地社区解释科学研究。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.