Evolution of Circumgalactic Gas Flows

这个项目延续了之前的奖项，将继续研究质量、能量和比氦(金属)更重的元素如何在星系中目前存在的恒星质量的一半形成期间循环进出星系的问题。根据先前的奖励，提议团队获得了数百个星系在相关红移范围内的光谱。他们将使用这些数据将星系质量-金属丰度关系扩展到较低的恒星质量，并将使用现有的和新的积分场光谱数据来研究激波激发对金属丰度诊断的影响。将利用凯克天文台和甚大望远镜上提供的新仪器获得新的观测结果，重点是详细的后续光谱学。该团队将利用荧光线发射来尝试解决从被发射部分填充的吸收线获得的不一致的银河系风速，并将通过采用为热星风开发的理论以及通过三维流体动力学模拟的数值射线跟踪来改进他们对线型的建模。作为一个副产品，该团队将提高对流出属性和星系属性之间的比例关系的了解，并限制加速机制的物理性质。该项目为一名女科学家的博士后学者任命的第三年提供支助，并资助一名研究生的论文研究；首席调查员将继续其社区外联活动方案。该团队打算将他们的线拟合代码和他们对超暗发射线星系的调查数据公之于众。

This project, renewing a previous award, will continue work on the problem of how mass, energy, and elements heavier than helium ("metals") cycle in and out of galaxies over the interval when half the stellar mass now present in galaxies was forming. Under the prior award, the proposing team acquired spectra of several hundred galaxies in the relevant range of redshifts. They will use these data to extend the galaxy mass-metallicity relation to lower stellar masses, and will investigate the effect of shock excitation on metallicity diagnostics using both existing and new integral-field spectroscopic data. New observations will be obtained using new instrumentation becoming available at the Keck Observatory and on the Very Large Telescope, with an emphasis on detailed follow-up spectroscopy. The team will make use of fluorescent line emission to try to resolve discrepant galactic wind velocities obtained from absorption lines partially filled by emission, and will improve their modeling of line profiles, by adapting a theory developed for hot star winds and also by numerical ray tracing through a 3-dimensional hydrodynamic simulation. As a byproduct, the team will improve knowledge of the scaling relations between outflow properties and galaxy properties, and constrain the physical nature of the acceleration mechanism. The project provides support for the third year of a Postdoctoral Scholar appointment for a female scientist and funds the dissertation research of a graduate student; and the Principal Investigator will continue her program of community outreach activities. The team intends to make their line-fitting code and the data from their survey for ultra-faint, emission-line galaxies publically available.