NOAO >   Observing Info >   Approved Programs >   2003B-0348

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Proposal Information for 2003B-0348


PI: Fred Hamann, University of Florida, hamann@astro.ufl.edu
Address: Astronomy Department, 211 Bryant Space Science Center, PO Box 112055, Gainesville, FL 32653-2055, USA

Title: Quasars and the Epoch of First Star Formation

Abstract: There is growing evidence that quasars reside in metal-rich environments out to redshifts beyond four. If confirmed, these results would imply that quasar environments, presumably young galactic (or proto-galactic) nuclei, have already experienced extensive star formation before the quasars became observable. This may represent the first major star formation after the Big Bang. However, nearly all of the abundance results for high-redshift quasars are based on uncertain emission line analyses. I propose Keck/HIRES observations of ``associated'' absorption lines (AALs) in high-redshift quasars to obtain the most reliable abundance data at the highest possible redshifts. Specifically, I will measure the gas-phase metallicities and Fe/(alpha)-element abundance ratios to estimate the age and evolutionary status of the surrounding stellar populations. The age constraint comes from Fe/(alpha) via the delay of roughly 1 Gyr in the Fe enrichment by Type Ia supernovae. In high-redshift quasars, this ~1 Gyr ``clock" will help define the epoch of first star formation after the Big Bang.


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