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

当我们用现代望远镜观察太空深处时，有限的光速使我们能够看到星系在遥远的过去的样子。我们从这样的观察中了解到，大多数星系在年轻时都经历了快速的恒星形成，随着年龄的增长，恒星形成的速度也在下降。尽管如此，恒星形成停止的速度有很大的不同，我们也不能完全理解为什么星系中恒星形成的速度会发生变化。是老化的星系耗尽了燃料，还是由于某种原因燃料变得无法使用？提高我们的知识的一种方法是把恒星形成速率和冷氢气联系起来，冷氢气是恒星形成的燃料。该项目的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，该项目将为少数民族背景的学生拓展科学职业道路。研究体验是为从军事领域过渡到STEM领域的士兵设计的。该团队计划进行各种各样的观测，包括空间分辨的CO发射测量，追踪分子气体含量，以及光学积分场单位（IFU）光谱调查，追踪年轻和年老的恒星群。研究人员已经将他们的测量结果合并到星系演化的星系外数据库（EDGE）中，现在准备将这些研究扩展到气体含量和恒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，从而允许对星系结构和环境等因素进行定量考虑。需要解决的关键问题之一是，恒星形成的停止主要是由可用气体供应的耗尽还是由气藏性质的变化引起的。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。

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.