暗分子云的精细结构、磁场和演化：HI窄线自吸收的高分辨率观测

The observational study of the atomic gas component in the primitive molecular clouds is essential to understand the formation, evolution and energy equilibrium of molecular clouds, as well as the initial conditions of star formation. The HI Narrow Self-Absorption (HINSA) line is a powerful tool to detect the atomic gas in cold dark clouds, and it is unique to reveal the fine structures and magnetic fields in dark clouds. We plan to use interferometers to observe the cold dark clouds in our Galaxy and Large Magellanic Cloud (LMC) via HINSA with high velocity resolutions, high angular resolutions and high sensitivities, and use both large single dishes and interferometers to detect Zeeman splitting in HINSA through deep integration. Based on these observations, we will be able to reveal the fine structures, velocity fields and magnetic fields inside dark clouds. Along with the results of molecular lines and dust continuum at other wavelengths, we will analyze the relationship between the atomic and molecular gas. Eventually, based on these results, we will greatly advance our understanding on the formation and evolution of molecular clouds and the initial conditions of star formation. Besides, the development of the method of analyzing and modeling HINSA will be helpful to the results of future FAST HI surveys.

对暗分子云中原子气体成分的观测对于理解分子云的形成、演化和能量平衡，以及恒星形成的初始条件至关重要。中性氢窄线自吸收（HINSA）是我们观测暗分子云中原子气体的有力手段，是揭示暗分子云精细结构和磁场的独一无二的有力工具。我们计划利用干涉仪通过HINSA对银河系和大麦哲伦云中的暗分子云进行高速度分辨率、高空间分辨率和高灵敏度的观测研究，并用大口径单天线和干涉仪对河内暗分子云进行深度积分观测以探测Zeeman分裂。通过这些观测，我们将能够揭示暗分子云中精细的空间结构和速度场信息，测量暗分子云内部的磁场。我们还将结合其他波段上的分子谱线及尘埃连续谱的数据，通过对比分析分子云中原子氢气体和分子气体的空间关系。最终，我们将大大加深对分子云的形成、演化和恒星形成初始条件的理解。此外，对HINSA观测经验的积累，数据处理方法和模型分析的发展也将有助于我国将来FAST中性氢巡天计划的确立和成果产出。