CAREER: Probing the High-Redshift Universe with Quasar Element Abundances

University Of Florida, Gainesville FL

Investigators

Abstract

AST-9984040 HAMANN Quasars (or QSOs) are bright beacons at the fringes of the observable universe. The light we measure today from the most distant of these objects was emitted when the universe was about 17% of its present age - roughly 1-2 billion years old. Spectroscopic studies show that even at these early times quasars contain heavy elements (or "metals"'), presumably a synthesized by local stars. This project is a five-year program to use quasar elemental abundances as tracers of star formation and galaxy evolution at early cosmological epochs. The enrichment time scales and physical conditions inferred from the abundances (such as the ages, gravitational binding energies, and perhaps total masses of the star-forming environments) should also help constrain models of the cosmology itself. Early-epoch star formation and galaxy evolution are among the most active research topics in astronomy today. This program's emphasis on the abundances near QSOs will provide a vital complement to other studies that probe more extended structures or use very different data and analysis techniques. The results will be particularly valuable for their unique constraints on galactic nuclear evolution. It has been shown that reliable abundances and important star-formation properties can be derived from the intrinsic emission and absorption lines in quasar spectra. This program will test and expand upon those results by 1) including larger QSO data samples - with an emphasis on the earliest epochs, 2) developing and comparing more independent abundance diagnostics, 3) targeting specifically the relative iron abundances to constrain the enrichment time scales, and 4) comparing the QSO results directly to other studies of high-redshift star formation and galaxy evolution. The same data and analyses will also necessarily address a variety of problems concerning the QSOs themselves. The results of the investigations will allow one to address fundamental issues, such as the formation and evolution of QSOs, and the origin, location, dynamics and physical nature of their environments. An integral part of the program is a long-range plan for education and public outreach. This plan includes 1) strategies for bringing science to K-12 students and the general public, 2) new interactive and "hands-on"' programs for undergraduates, and 3) a mentoring plan for graduate students that will prepare them for a range of career options, including education, industry and academic research. The goal is to design projects for graduate student classes that will enhance their skills in "practical" applications, team management, communication and organization. Meetings with industry representatives will be arranged and the students will be sent out to local industry centers and industry representatives will be invited to visit the astronomy department. A weekly series of journal club talks (for students and faculty) will be organized and the graduate students will go out into local K--12 schools to participate in a program of public outreach. This outreach program will benefit the K-12 students by stirring their enthusiasm for science and by having the graduate students be examples of positive role models. The undergraduate education plan includes innovative classroom techniques such as "concept testing," exposure to current research as part of the normal curriculum, and summer research projects for motivated juniors and seniors. The Division of Astronomical Sciences provides support for this project. ***