Collaborative Research: Spatially Resolving the Mechanisms of Star Formation Quenching Using Molecular Gas Observations

当我们用现代望远镜向太空深处看时，有限的光速使我们能够看到遥远过去出现的星系。 我们从这些观测中了解到，大多数星系在年轻时经历快速的星星形成，而随着年龄的增长，星星形成逐渐减少。 尽管如此，星星形成停止的速度有很大的差异，我们也不完全理解星系中星星形成速度变化的原因。 老化的星系是燃料耗尽了，还是燃料由于某种原因变得无法使用了？ 其中一种方法是将星星的形成速率与冷氢气（星星形成的燃料）联系起来。 项目研究人员将利用最近完成的对附近星系的调查以及最先进的计算机模型来实现这一目标。 通过研究经验和指导，该项目将扩大来自少数民族背景的学生的科学生涯的途径。 该团队计划进行各种各样的观测，包括追踪分子气体含量的CO发射的空间分辨测量，以及追踪年轻和年老恒星种群的光学积分场单元（IFU）光谱调查。 研究人员已经将他们的测量结果合并到银河系外星系演化数据库（EDGE）中，现在准备将这些研究扩展到气体含量和星星形成活动低得多的星系。 他们将进行和分析高分辨率的模拟，将进化情景与观测预测相匹配，从而定量考虑星系结构和环境等因素。 其中要解决的关键问题是，星星形成的停止是否主要是由可用气体供应的耗尽或天然气储层性质的变化驱动的。该奖项反映了NSF的法定使命，并已被认为是值得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的支持。

When we look deep into space with modern telescopes, the finite speed of light enables us to see galaxies as they appeared in the distant past. What we have learned from such observations is that most galaxies experience rapid star formation in their youth and declining star formation as they age. Still, there are wide variations in how quickly star formation stops, and we do not fully understand why the rate of star formation in galaxies changes. Have aging galaxies just run out of fuel, or has the fuel become unusable for some reason? One way to advance our knowledge is to make connections between the star formation rate and the cold hydrogen gas which is the fuel for star formation. The project investigators will take advantage of recently completed surveys of nearby galaxies, as well as state-of-the-art computer models, to pursue this goal. Through research experiences and mentoring, the project will expand pathways to scientific careers for students from minority backgrounds. The research experiences are designed for soldiers transitioning from the military to STEM fields.The team plans a wide variety of observations, including spatially resolved measurements of CO emission, which trace the molecular gas content, and optical integral field unit (IFU) spectroscopic surveys, which trace the young and old stellar populations. The investigators have merged their measurements into the Extragalactic Database for Galaxy Evolution (EDGE) and are now poised to extend these studies to galaxies with much lower gas content and star formation activity. They will conduct and analyze high-resolution simulations that match evolutionary scenarios to observational predictions, allowing factors such as galaxy structure and environment to be considered quantitatively. Among the key questions to be addressed are whether the cessation of star formation is driven largely by exhaustion of the available gas supply or by changes to the properties of the gas reservoir.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.