New Views of Warm Molecular Gas in Nearby Galaxies

Julia Kamenetzky博士被授予美国国家科学基金会天文学和天体物理学博士后奖学金，在亚利桑那大学开展研究和教育项目。她将研究星系中的分子气体，这是恒星形成的原料；这种气体足够冷，原子可以结合成分子。这项研究将结合来自阿塔卡马大型毫米波阵列（ALMA）的高分辨率分子气体图，以观察少数星系的精美细节，以及对许多星系的低分辨率观测，以在大样本中寻找模式。通过比较不同类型星系中气体的条件，她将帮助我们了解哪些物理过程对增加和减少恒星形成最重要。恒星的诞生和死亡显著地影响着星系的能量和化学成分；这个项目的目标是研究恒星形成的原料——分子气体，使用的是天文学家现在才掌握的新技术。此外，Kamenetzky博士将与天文教育中心（CAE）一起开发和分发新的以研究为基础、以学生为中心的射电天文学课程。来自赫歇尔的新数据表明，高能的CO旋转谱线（例如CO J=6-5）是由温暖的分子气体发出的，这与由CO J=1-0追踪到的较冷的分子气体不同。Kamenetzky博士建议用ALMA以高分辨率测量这种温暖的CO气体的未知形态和运动学，以了解它与已被充分研究的星系成分的关系，并揭示其激发机制。此外，亚利桑那射电天文台将与赫歇尔尖塔的高j谱线结合，获得新的低j CO谱线单盘观测结果，以便同时模拟多达300个星系的大型参考样本中气体的冷/热成分。类似的方法将应用于最近在超新星1987A残骸中发现的分子CO和SiO的新的ALMA 3D多普勒断层扫描图。新的射电天文学课程将通过天文教育中心（CAE）广泛分发，该中心是一个公认的研究型教育材料和讲习班的提供者。

Dr. Julia Kamenetzky is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at the University of Arizona. She will study the molecular gas throughout galaxies that is the raw material for star formation; this gas is cold enough that atoms can bind together into molecules. This study will occur with a combination of high-resolution maps of molecular gas from the Atacama Large Millimeter Array (ALMA) to see exquisite detail in a few galaxies, and low-resolution observations of many galaxies to search for patterns in a large sample. By comparing the conditions of the gas in different types of galaxies, she will add to our understanding of which physical processes are most important for increasing and decreasing star formation. The birth and death of stars significantly impact the energetic and chemical composition of galaxies; the goal of this project is to study the raw material of star formation, molecular gas, using new technology that has only now become available to astronomers. Additionally, Dr. Kamenetzky will develop and distribute new research-based, student-focused radio astronomy curriculum with the Center for Astronomy Education (CAE).New data from Herschel indicates that higher-energy CO rotational lines (e.g. CO J=6-5) are emitted from warm molecular gas that is distinct from the well-studied cooler molecular gas traced by e.g. CO J=1-0. Dr. Kamenetzky proposes to measure the yet-unknown morphology and kinematics of this warm CO gas in high resolution with ALMA to understand its relation to well-studied galaxy components and reveal its excitation mechanisms. Additionally, new single-dish observations of low-J CO lines will be obtained using the Arizona Radio Observatory, to be combined with high-J lines from Herschel SPIRE, in order to simultaneously model the cool/warm components of gas in a large reference sample of up to 300 galaxies. Similar methods will be applied to new ALMA 3D Doppler tomography maps of recently discovered molecular CO and SiO in the remnant of Supernova 1987A. New radio astronomy curriculum will be widely distributed via the Center for Astronomy Education (CAE), a recognized provider of research-based educational materials and workshops.