PI: John M. O'Meara, Saint Michael's College, email@example.com
Address: Chemistry and Physics, One Winooski Park, Colchester, VT 05439, United States
CoI: Jason X. Prochaska, University of California, Santa Cruz
Title: The Optical Depth of the Universe and the Search for Missing Metals at 2.5 < z < 3.4
Abstract: We propose to complete our program of obtaining 100 spectra of bright z ~ 3.2 quasars drawn from the Sloan Digital Sky Survey and other surveys using the MagE spectrograph on Magellan. This sample will constitute a blind search for absorption systems that have optical depths (tau)_LL ~ 0.1 - 3 at the Lyman limit. Such systems are purported to dominate the opacity of the universe at 1 Ryd. In turn, their incidence is critical for estimates of the extragalactic UV background and the processes of reionization (both HI and HeII). MagE, with its modest resolution and high throughput at (lambda) < 4000\AA, is currently the optimal instrument for this experiment. In addition, we will use the large wavelength coverage afforded by MagE to perform a census of the metallicities of these systems which may dominate the metal census at z ~ 3.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360