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

当我们用现代望远镜深入太空时，有限的光速使我们能够看到遥远的过去出现的星系。我们从这样的观测中了解到的是，大多数星系在年轻时经历了快速的恒星形成，而随着年龄的增长，恒星的形成逐渐减少。尽管如此，恒星形成停止的速度存在很大的差异，我们也不完全理解为什么星系中的恒星形成速度会发生变化。是老化星系的燃料耗尽了，还是因为某种原因燃料变得不可用了？提高我们认识的一种方法是将恒星形成率与恒星形成的燃料--冷氢气体联系起来。项目调查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，该项目将为少数族裔背景的学生拓展通往科学职业的途径。研究经验是为从军事领域过渡到STEM领域的士兵而设计的。该团队计划进行广泛的观测，包括追踪分子气体含量的CO排放的空间分辨率测量，以及追踪年轻和老年恒星群体的光学积分场单位(IFU)光谱测量。研究人员已经将他们的测量结果合并到星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恒星形成活动要低得多的星系。他们将进行和分析高分辨率模拟，将演化情景与观测预测相匹配，从而能够定量地考虑星系结构和环境等因素。需要解决的关键问题是，恒星形成的停止主要是由于可用气体供应耗尽还是由于气藏属性的变化。这一裁决反映了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。

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.