Characterizing the Molecular Gas Contents of High Redshift Galaxies

天体物理学家刚刚开始解开早期宇宙的细节和恒星形成的历史。由于分子气体是恒星形成的燃料，了解它在大多数恒星形成时的特征是至关重要的，当时宇宙大约是现在年龄的15%。这个项目的目的是测试星系形成的理论图景，该图景做出了非常可靠的预测，即非常遥远的恒星形成星系拥有大量的气藏。首席研究员(PI)将对非常遥远(高红移)星系中的分子气体进行彻底的表征。这项计划涉及一项在新启用的射电和毫米干涉仪上进行的多年观测计划。这些观测将用于测量最遥远星系团之一的七个恒星形成星系中一氧化碳(CO)的基态发射。利用这些数据，PI将得出气体质量、气体消耗时间、恒星形成效率、动力学质量和气体分数，并将通过这种稳健的测量将总可用样本增加三倍。PI将对大约30个星系进行类似的分析，目标是一组新发现的高红移过密度星系。这个样本量将使我们能够对气体含量和气体的物理条件作为红移和恒星质量的函数进行独特的研究。这项分析将是第一次研究高红移星系的分子气体含量如何依赖于它们的环境。在教育方面，PI将在劳伦斯高中设计和实施一项外展计划。这个项目的目标是教授研究技术、科学的本质和电磁频谱。该项目的学生将使用斯皮策太空望远镜的数据来测量星系团的恒星形成率。该项目将涉及20名学生，为期两年。最优秀的两名学生将在美国天文学会的一次会议上展示他们的发现。该项目将由该校的一名物理教师、一名研究生和PI联合运营。通过为高中教师提供继续教育的机会，并为教师提供研究工具和数据，该计划将变得自给自足。这些活动的成效将得到严格和定量的评估。PI还将与本科生一起进行研究，本科生将在美国天文学会的一次会议上展示他们的发现。国际天文台还将在靠近国际天文台的机构组织河外天文学家及其学生的年度会议，以便为学生提供交流想法和介绍他们的研究的机会。

Astrophysicists are just beginning to unravel the details of the early Universe and the history of star formation. Because molecular gas is the fuel for star formation, it is crucial to understand its characteristics when most stars formed, a time when the Universe was about 15% of its current age. The aim of this project is to test the theoretical picture of galaxy formation that makes the robust prediction that very distant star forming galaxies have large gas reservoirs. The principal investigator (PI) will perform a thorough characterization of molecular gas in very distant (high redshift) galaxies. This project involves a multi-year observing program conducted at newly commissioned radio and millimeter interferometers.These observations will be used to measure the ground state emission from carbon monoxide (CO) in seven star forming galaxies in one of the most distant known galaxy clusters. With these data the PI will derive the gas mass, gas consumption timescales, star formation efficiencies, dynamical masses, and gas fractions, and will increase the total available sample with such robust measurements by a factor of three. The PI will perform a similar analysis of about 30 galaxies by targeting a set of newly discovered high redshift over-densities. This sample size will enable a unique study of the gas contents and the physical conditions of the gas as a function of redshift and stellar mass. This analysis will be the first examination of how the molecular gas contents of high redshift galaxies depend on their environment.Educationally, the PI will design and implement an outreach program at Lawrence High School. The goals of this program are to teach research techniques, the nature of science, and the electromagnetic spectrum. Students in this program will use data from the Spitzer Space Telescope to measure the star formation rates of cluster galaxies. The program will involve 20 students and span over two years. The best two students will present their findings at an American Astronomical Society meeting. The program will be jointly run by a physics teacher at the school, a graduate student, and the PI. By providing opportunities for continuing education to the high school teacher and by providing the teacher with research tools and data, this program will become self-sustaining. The effectiveness of the activities will be rigorously and quantitatively assessed. The PI will additionally perform research with undergraduates, who will present their findings at an American Astronomical Society meeting. The PI will also organize an annual meeting of extragalactic astronomers and their students at institutes close to the PI's institution in order to provide opportunities for the students to exchange ideas and present their research.