New Probes of Galactic Outflows at the Peak Epoch of Star Formation

银河系的形成受气体大规模外流形式的反馈调节。由于很难观察到气体发出的微弱辐射，人们对这一过程的细节知之甚少。首席研究员(PI)琼斯发现了一个引力透镜星系的样本，在这个样本中，前景星系弯曲了来自遥远星系的光线，放大了其微弱的发射。PI将使用W.M.Keck天文台的Keck宇宙网成像仪(KCWI)观测这些透镜星系，以研究100亿年前星系外流是如何形成它们的。作为该项目的一部分，PI将在加州州立大学数学与科学暑期学校(COSMOS)向高中生教授科学研究方法，讲授星系和宇宙学，并使用加州大学戴维斯分校的屋顶望远镜设施介绍观测天文学技术。这项提议将支持对现有数据的分析和对更大样本的补充观察。使用KCWI仪器的积分场光谱将使用荧光发射线绘制流出气体的空间范围和运动学图，这将改进对质量损失率的估计。同样的数据还可以绘制吸收过程中流出的气体的地图，探测流出的能量和发射点以及化学成分。非难熔元素硫提供了相对于中性氢的总阿尔法元素金属丰度的测量，而其他元素，如硅和镍，对粉尘含量和丰度模式很敏感。总而言之，这些结果将解决星系外流的物理性质及其在红移z=2-3的星系聚集中的调节作用。这一奖项反映了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。

Galaxy formation is regulated by feedback in the form of large-scale outflows of gas. The details of this process are poorly understood as it is difficult to observe the faint emission from the gas. Principal Investigator (PI) Jones has identified a sample of gravitationally lensed galaxies, where a foreground galaxy bends the light from the distant galaxy and magnifies its weak emission. The PI will observe these lensed galaxies using the Keck Cosmic Web Imager (KCWI) instrument at the W. M. Keck Observatory to study how galactic outflows shaped their formation ten billion years ago. As part of this program the PI will teach scientific research methods to high school students in the California State Summer School for Mathematics and Science (COSMOS), with lectures on galaxies and cosmology, and an introduction to observational astronomy techniques using a rooftop telescope facility at the University of California - Davis campus. This proposal will support the analysis of data already in hand and additional observations of a larger sample. Integral field spectroscopy with the KCWI instrument will map the spatial extent and kinematics of outflowing gas using fluorescent emission lines, which will improve estimates of the mass loss rates. The same data also enable maps of the outflowing gas in absorption, which probes outflow energetics and launching sites as well as the chemical composition. The non-refractory element sulfur provides a measurement of total alpha-element metallicity relative to neutral hydrogen, while other elements such as silicon and nickel are sensitive to dust content and abundance patterns. Collectively these results will address the physical properties of galactic outflows and their role in regulating galaxy assembly at redshifts z=2-3.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.