Characterizing the Molecular Gas Contents of High Redshift Galaxies

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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.