Southern Serpents: The Internal Structure of Interstellar Filaments in the Fourth-Quadrant of the Milky Way

几乎所有恒星的诞生地都位于银河系圆盘中的星际分子云中。先前对银河系盘的观测表明，许多这样的云在很大的物理尺度上都是连续的。 虽然天文学家同意恒星是在星际云的致密区域内形成的，但他们目前还不了解星际细丝对星星形成过程的重要性。测量星际云三维结构的唯一方法是通过光谱无线电观测。研究人员将使用三个光谱调查协调一致，以探测南银河平面内星际细丝的原子和分子内部结构。 主要的研究目标是：1）描述细丝的速度结构，并将其与数值模型进行比较，以得出有关其寿命，稳定性和恒星形成效率的结论，2）利用原子和分子观测的高阶统计量追踪细丝的湍流结构。研究人员是威斯康星州大学的志愿者-麦迪逊麦克奈尔学者计划作为科学技术工程和数学（STEM）专业顾问，旨在为第一代，低收入和少数民族本科生准备研究生院及以后。 这项研究还将为本科生提供培训和指导的机会。如果无定形云是唯一密度大到足以形成恒星的结构，那么银河系星星形成理论需要集中在无定形分子云的形成和演化上，包括发生原恒星活动的无定形子结构。 该研究项目将通过对分子气体和原子包层的光谱观测，直接识别和表征星际细丝，从而做出贡献。 主要的数据产品之一将是一个细丝目录，沿着对它们进行动力学研究的结果。这将使未来的研究原恒星的活动驻留在有关的行星结构。

The birthplace of nearly all stars lies within the interstellar molecular clouds that reside in the disk of the Milky Way Galaxy. Previous observations of the Galactic disk suggest that many of these clouds are filamentary over a wide range of physical scales. While astronomers agree that stars form within the densest regions of interstellar clouds, they currently do not understand the importance of interstellar filaments for the process of star formation. The only way to measure the three-dimensional structure of interstellar clouds is through spectroscopic radio observations. The investigator will use three spectroscopic surveys in concert to probe both the atomic and molecular internal structure of interstellar filaments within the southern Galactic plane. The main research objectives are to 1) characterize the velocity structure of the filaments and compare this to numerical models to draw conclusions about their lifetimes, stability and star-formation efficiencies, 2) trace the turbulent structure of the filaments using higher order statistics on both the atomic and molecular observations.The investigator volunteers with the University of Wisconsin-Madison McNair Scholars Program as a Science Technology Engineering and Mathematics (STEM) Professional Advisor aimed at preparing first-generation, low-income, and minority undergraduates for graduate school and beyond. This research will also provide training and mentoring opportunities for undergraduate students.If filamentary clouds are the only structures with densities large enough to form stars, then the theory of Galactic star formation needs to be focused on the formation and evolution of filamentary molecular clouds, including filamentary sub-structures where proto-stellar activity occurs. This research project will make a contribution by directly identifying and characterizing interstellar filaments through spectroscopic observations of both their molecular gas and atomic envelopes. One of the main data products will be a catalog of filaments, along with the results from the dynamical studies done on them. This will allow future research on where proto-stellar activity resides in relation to filamentary structure.