NSF Young Investigator: Structure of the Interstellar Medium

NSF 青年研究员：星际介质的结构

• 批准号: 9457456
• 负责人: Alyssa Goodman
• 金额: $ 27.5万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-08-01 至 1999-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9457456&HistoricalAwards=false
• 关键词: NSF; Young; Investigator; Structure; Interstellar

9457456 Goodman Dr. Goodman will carry out research to seek to explore the question of which physical processes are most important in determining the structure and evolution of interstellar clouds in our Galaxy. These "clouds", as they are known, are just local density enhancements in the lower-density interstellar medium (ISM), but they are nonetheless the object of intense study, primarily because they are the birthplaces of new stars in our Galaxy. Without a clear physical picture of these clouds, it is very difficult, if not impossible, to develop and refine a physically realistic scenario for the star formation process itself. Dr. Goodman, in carrying out the research, will specifically seek to explore the relationship between magnetic fields, density structure, and velocity structure in the interstellar medium (ISM). Prior research carried out by Dr. Goodman and collaborators has shown that the magnetic and kinetic energies measured in the gaseous ISM are usually similar, so it is reasonable to hypothesize that the magnetic fields pervading the gas and velocity structure in the gas are related. One of the biggest pieces missing from the picture of the interaction between magnetic fields and gas in the ISM is a clear view of magnetic field structure in the dense gas where stars form. The observation of the polarization of optical and near-infrared background starlight can be used to map field structure in low-density gas, but Dr. Goodman's recent research has shown that this technique cannot trace the field accurately in denser gas. Dr. Goodman and collaborators will therefore carry out far-infrared and sub-millimeter wavelength observations of the polarized emission from magnetically aligned dust in dense regions of the ISM. The results of the research should provide a clearer view of the field structure there. The observations will be carried out through several international collaborations, one of which will seek to use the new infrared satellite observatory (ISO). Velocity structure of the ISM will be investigated with new spectral-line mapping of gas in the interstellar medium and through theoretical modeling of new and existing data. Dr. Goodman's current students and research assistants will be primarily working on this line of inquiry. Early results of the research have shown that "dense cores", which are the dense knots of gas associated with the formation of individual stars, may represent "eddies" in a more turbulent/wavelike velocity field which characterizes the lower-density surrounding ISM. The new studies will focus on relating the velocity structure deduced from spectral-line mapping to realistic views of the magnetic field in the ISM obtained from far-infrared and sub-mm polarimetry. This award is to recognize an outstanding young faculty member in science and engineering. The award will enhance the career of the faculty member by providing flexible support for research and educational activities. Cooperation with industry and institutions that support research and education is encouraged.

9457456古德曼古德曼博士将进行研究，试图探索哪些物理过程在决定我们银河系星际云的结构和演化中最重要的问题。众所周知，这些“云”只是低密度星际介质（ISM）中的局部密度增强，但它们仍然是深入研究的对象，主要是因为它们是我们银河系中新恒星的诞生地。如果没有这些云的清晰的物理图像，要发展和完善恒星形成过程本身的物理现实场景是非常困难的，如果不是不可能的话。古德曼博士在进行这项研究时，将特别寻求探索星际介质（ISM）中磁场、密度结构和速度结构之间的关系。Goodman博士及其合作者先前的研究表明，气体ISM中测量的磁场和动能通常是相似的，因此可以合理地假设气体中的磁场和气体中的速度结构是相关的。在ISM中，磁场和气体之间相互作用的图像中缺失的最大部分之一是对恒星形成的致密气体中磁场结构的清晰视图。观测光学和近红外背景星光的偏振可以用来绘制低密度气体中的场结构，但古德曼博士最近的研究表明，这种技术不能准确地追踪密度更大的气体中的场。因此，古德曼博士和合作者将对ISM密集区域磁排列尘埃的偏振辐射进行远红外和亚毫米波观测。研究的结果应该提供一个更清晰的现场结构的看法。这些观测将通过若干国际合作进行，其中一个将寻求使用新的红外卫星天文台（ISO）。ISM的速度结构将通过星际介质中气体的新谱线映射以及对新数据和现有数据的理论建模来研究。古德曼博士目前的学生和研究助理将主要从事这方面的研究。研究的早期结果表明，“致密核心”，即与单个恒星形成有关的致密气体结，可能代表了更湍流/波状速度场中的“涡流”，这是ISM周围低密度的特征。新的研究将集中在将从谱线映射推断出的速度结构与从远红外和亚毫米偏振法获得的ISM磁场的实际视图联系起来。这个奖项是为了表彰在科学和工程领域杰出的年轻教员。该奖项将通过为研究和教育活动提供灵活的支持，提高教师的职业生涯。鼓励与支持研究和教育的工业和机构合作。