The Physical Properties of Cold Gas in External Galaxies (Extragalactic Astronomy)

本项目将重点研究星系中分子和原子云的分布和物理性质及其与恒星形成的关系。分子云是通过一氧化碳的毫米波发射来追踪的，而原子气体是通过中性氢（HI）的21厘米辐射来观察的。恒星形成区域的分布将由对电离氢的观测来确定。本研究将解决以下具体问题：(1)螺旋密度波对分子云和局部恒星形成效率的影响；(2)迟型星系核盘中分子气体的物理性质；(3)透镜状星系中星际介质的演化起源；(4) HI在矮不规则星系分子云屏蔽中的作用。这项工作将导致对调节星系恒星形成历史的全局和局部过程的更好理解。该项目还进一步推进了VPW项目的目标，即为女性提供通过研究提升她们在科学或工程领域的职业生涯的机会，并通过研究人员在东道国校园中作为榜样的知名度来鼓励其他女性在这些领域追求职业。在这个项目中，有助于实现第二个目标的拟议活动包括：主持一次射电天文学高级专题研讨会；教授大三、大四物理专业天体物理学课程《星系与宇宙学》；每学期至少有一名学生参与研究的某些方面；物理实验室导论教学；并进行一般性的座谈会。

This project will focus on the distributions and physical properties of molecular and atomic clouds in galaxies and their relations to star formation. The molecular clouds are traced by millimeter wave emission from carbon monoxide, and the atomic gas is seen via 21-cm radiation from neutral hydrogen (HI). The distributions of star forming regions will be determined by observations of ionized hydrogen. This research will address the specific problems of: (1) the effects of spiral density waves on the molecular clouds and the local star formation efficiency; (2) the physical properties of the molecular gas in the nuclei and disks of late-type galaxies; (3) the evolution origin of the interstellar medium in lenticular galaxies; and (4) the role of HI in molecular cloud shielding within dwarf irregular galaxies. This work will lead to an improved understanding of the global and local processes which regulate the star formation histories of galaxies. The project also furthers VPW program objectives to provide opportunities for women to advance their careers in science or engineering through research, and to encourage other women to pursue careers in these areas through the investigators' enhanced visibility as role models on the host campuses. In this project, the proposed activities which contribute to the second objective include: leading an advanced topics seminar on radio astronomy; teaching, "Galaxies and Cosmology", an astrophysics course for junior and senior physics majors; involving at least one student per semester in some aspect of the research; teaching Introductory Physics laboratories; and delivering general colloquia.