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

南方蛇：银河系第四象限星际细丝的内部结构

• 批准号: 1517573
• 负责人: Audra Hernandez
• 金额: $ 36.81万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1517573&HistoricalAwards=false
• 关键词: Southern; Serpents; Internal; Structure; Interstellar

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.

几乎所有恒星的诞生地都位于银河系盘状星际分子云内。之前对银盘的观察表明，这些云团中的许多是在广泛的物理尺度上呈丝状的。虽然天文学家一致认为恒星是在星际云最密集的区域形成的，但他们目前并不了解星际细丝在恒星形成过程中的重要性。测量星际云三维结构的唯一方法是通过射电光谱观测。研究人员将同时使用三种光谱测量来探测银河系南部平面内星际细丝的原子和分子内部结构。主要研究目标是1)表征细丝的速度结构，并将其与数值模型进行比较，以得出关于它们的寿命、稳定性和恒星形成效率的结论；2)使用原子和分子观测的高阶统计量来追踪细丝的湍流结构。研究人员自愿加入威斯康星大学麦迪逊麦克奈尔学者项目，作为科学技术工程与数学(STEM)专业顾问，旨在为第一代、低收入和少数族裔本科生准备研究生及以后的学习。这项研究还将为本科生提供培训和指导机会。如果丝状云是密度足以形成恒星的唯一结构，那么银河系恒星形成理论需要专注于丝状分子云的形成和演化，包括发生原恒星活动的丝状亚结构。这一研究项目将通过对星际纤维分子气体和原子包层的光谱观测，直接识别和表征星际纤维，从而做出贡献。主要的数据产品之一将是细丝目录，以及对它们进行的动力学研究的结果。这将使未来能够研究原恒星活动与丝状结构的关系。