A Study of Magnetic Fields in Interstellar Molecular Clouds

伊利诺伊大学的Richard Crutcher博士和他在肯塔基大学的同事Thomas Troland博士将继续一个非常成功的长期项目，测量星际云中的磁场强度，他们将把这个项目扩展到新的领域。利用新墨西哥州的甚大阵列，一项重要的工作将是绘制来自星际云的中性原子氢和羟基线的塞曼效应分布图。该项目的另一部分是继续利用西弗吉尼亚州国家射电天文台和波多黎各国家天文和电离层中心的望远镜，对朝向乌云中心区域的羟基光谱线进行塞曼效应的调查观测。单天线测量磁场强度将扩展到密集的区域，通过观察3毫米线的塞曼效应。这个实验将首次允许在恒星形成过程的关键阶段直接探测磁场强度，当核心碎裂和坍缩发生时。该奖项支持的观测项目将为星际云磁场的理论研究提供基础测试。因此，这项研究将为理解磁场在致密星际云的演化和恒星形成中的作用提供必要的经验框架。

Dr. Richard Crutcher, at the University of Illinois, together with his colleague Dr. Thomas Troland, at the University of Kentucky, will continue a very successful long term program to measure magnetic field strengths in interstellar clouds, and they will extend the program into new areas. Using the Very Large Array in New Mexico, a major effort will be made to map the distribution of the Zeeman effect in lines of neutral atomic hydrogen and hydroxyl from interstellar clouds. Another part of the project is to continue survey observations of the Zeeman effect on spectral lines of hydroxyl toward central regions of dark clouds using telescopes at the National Radio Astronomy Observatory in West Virginia and at the National Astronomy and Ionosphere Center in Puerto Rico. Single-antenna measurements of magnetic field strengths will be extended to denser regions by observations of the Zeeman effect in the 3-mm lines of CN. This experiment will allow for the first time direct probing of magnetic field strengths at the crucial stage in the star formation process when core fragmentation and collapse are taking place. The observational program supported by this award will provide fundamental tests of theoretical studies of magnetic fields in interstellar clouds. This research will therefore lead to the essential empirical framework for understanding the role of magnetic fields in the evolution of dense interstellar clouds and in star formation.