Collaborative Research: Resolving Physical Conditions of Diffuse Ionized Gas throughout the Milky Way-Magellanic System

恒星诞生的气体云向我们展示了恒星对其周围环境的壮观影响。恒星的紫外光将电子从原子中剥离出来，使原子电离。这些自由电子最终再次与原子结合，发出能说明问题的颜色。在过去的几十年里，威斯康星州的H-Alpha测绘仪(WHAM)发现，整个天空都在发出微弱的红光，这些红光是由遍布银河系的电离氢原子发出的。WHAM小组一直在银河系及其邻近的卫星星系麦哲伦星云中探索这种“弥漫的电离气体”。Wham可以揭示出比猎户座星云微弱近1亿倍的辐射。WAM仍然是世界上研究天空中微弱的漫反射光最灵敏的仪器之一。该团队正在开发一种新的展览和教育活动，以帮助展示科学家如何使用光谱学来识别元素和探索遥远物体的性质。展览将利用与WHAM相同的法布里-珀罗技术吸引公众和学生团体。研究人员将继续为本科生和研究生提供极好的机会。在之前由NSF资助的研究中，WHAM调查人员进行了第一次调查，追踪了银河系和麦哲伦星云中扩散的电离气体。这些努力是对追踪其较冷、中性相的氢的无线电测量的补充。现在，从我们所在的银河系内部，从各个方向都能探测到中性和电离氢气的发射。有了这个奖项，研究人员利用WHAM开始了一个多样化的观测计划。通过捕捉其他元素的发射，他们正在追踪扩散气体中的温度和电离程度。这项新的研究促进了我们对星际物质、形成它的过程以及恒星如何影响我们银河系的理解。这一奖项反映了美国国家科学基金会的法定任务，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。

Clouds of gas, where stars are born, show us the spectacular impact of stars on their immediate surroundings. The stars’ ultraviolet light strips electrons from atoms, ionizing them. These free electrons eventually combine again with atoms and emit telltale colors. Over the last few decades, the Wisconsin H-Alpha Mapper (WHAM) discovered that the entire sky is glowing faintly in red light emitted by ionized hydrogen atoms that pervade the Milky Way. The WHAM group has been exploring this "diffuse ionized gas" throughout the Milky Way and its neighboring satellite galaxies, the Magellanic Clouds. WHAM can reveal emission nearly a 100-million times fainter than the Orion Nebula. WHAM remains one of the most sensitive instruments in the world for studying faint, diffuse light in our sky. The Team is developing a new exhibit and educational activities that will help show how scientists use spectroscopy to identify elements and explore the properties of distant objects. The exhibit will engage the public and student groups with the same Fabry-Perot technology used by WHAM. The investigators will continue to provide excellent opportunities for undergraduate and graduate students.During previous NSF-funded studies, WHAM investigators produced the first surveys that traced diffuse ionized gas in the Milky Way and the Magellanic Clouds. These efforts complement radio surveys of hydrogen that trace its cooler, neutral phase. Neutral and ionized hydrogen emission are now detected in every direction from our location inside the Galaxy. With this award, the investigators use WHAM to embark on a diverse observational program. Capturing emission from other elements, they are tracing the temperature and degree of ionization throughout the diffuse gas. This new study advances our understanding of interstellar matter, the processes that shape it, and how stars affect our Galaxy.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.