NOAO >   Observing Info >   Approved Programs >   2003B-0267

Small NOAO Logo

Proposal Information for 2003B-0267


PI: Chris D. Impey, University of Arizona, cimpey@as.arizona.edu
Address: Steward Observatory, 933 N. Cherry Ave, Tucson, AZ 85721, USA

CoI: Cathy E. Petry, University of Arizona
CoI: Kristoffer A. Eriksen, University of Arizona
CoI: Andrew R. Marble, University of Arizona
CoI: Lei Bai, University of Arizona

Title: Cosmology with Quasar Pairs

Abstract: We propose spectroscopy with GMOS on Gemini-S of 4 faint quasar pairs with angular separations in the range 2-4 arcmin, in order to address fundamental issues in cosmology. The spectra will yield measurements of the auto-correlation and cross-correlation power on scales of 1-100 h^-1 Mpc at z ~ 2 (numbers in this proposal are scaled to H_0=75 kms^-1 Mpc^-1). Results from numerical simulations and analytic calculations show that the neutral hydrogen traced by the Lyman-(alpha) ``forest'' is a powerful cosmological probe, since the gas density (measured by spectral absorption) maps in a simple way to the underlying mass density field. We will measure the relationship between the angular diameter and redshift distribution of the absorbers as a test of the geometry of space, enabling a measurement of (Lambda) that is totally independent of standard candle assumptions or issues of cosmic evolution. Most of this survey is being carried out with the MMT and Magellan - however quasar pairs of the appropriate redshift and angular separation are extremely rare. The success of this experiment depends on these faint, close separation pairs, and we request 2 nights with Gemini to augment our sample.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2003B-0267

noaoprop-help@noao.edu

Small NOAO Logo