NSF Young Investigator: Structure of the Interstellar Medium

9457456古德曼博士将开展研究，寻求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方面最重要的问题。这些“云”，正如它们所知，只是低密度星际介质(ISM)中的局部密度增强，但它们仍然是密集研究的对象，主要是因为它们是我们银河系新恒星的诞生地。如果没有一张清晰的这些云层的物理图像，就很难(如果不是不可能)为恒星形成过程本身开发和完善物理上现实的场景。在进行这项研究时，古德曼博士将专门探索星际介质(ISM)中磁场、密度结构和速度结构之间的关系。古德曼博士和他的合作者之前进行的研究表明，在气体ISM中测得的磁能和动能通常是相似的，因此可以合理地假设，气体中弥漫的磁场与气体中的速度结构有关。在ISM中磁场和气体相互作用的图像中，最大的缺失之一是对恒星形成的致密气体中磁场结构的清晰观察。光学和近红外背景星光的偏振观测可以用来绘制低密度气体中的场结构图，但古德曼博士最近的研究表明，这项技术无法在密度较高的气体中准确追踪场。因此，古德曼博士和他的合作者将对ISM密集区域中磁性定向尘埃发出的偏振辐射进行远红外和亚毫米波长的观测。研究结果应能更清楚地了解那里的油田结构。观测将通过几个国际合作进行，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和对新的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。早期的研究结果表明，“致密核”，即与单个恒星的形成有关的致密气体结，可能代表着一个更湍流/波浪状的速度场中的“漩涡”，这是ISM周围密度较低的特征。新的研究将侧重于将从谱线映射得出的速度结构与从远红外和亚毫米偏振测量获得的ISM中磁场的真实图像联系起来。这一奖项是为了表彰一位杰出的科学和工程领域的年轻教员。该奖项将通过为研究和教育活动提供灵活的支持来促进教师的职业生涯。鼓励与支持研究和教育的行业和机构合作。

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.