NOAO >   Observing Info >   Approved Programs >   2006A-0545

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Proposal Information for 2006A-0545


PI: Joseph F. Hennawi, UC Berkeley, joeh@berkeley.edu
Address: Astronomy Department, 601 Campbell Hall, Berkeley, CA 94720-3411, United States

CoI: Jason X. Prochaska, UCO/Lick
CoI: Michael A. Strauss, Princeton
CoI: Gordon Richards, Johns Hopkins
CoI: John O'Meara, MIT
CoI: Xiaohui Fan, Steward Observatory

Title: Characterizing the Environment, Emission Geometry, and Radiative History of Quasars using Projected Quasar Pairs

Abstract: We have obtained high S/N moderate and high resolution Gemini and Keck spectra of the Ly(alpha) forests of a large sample of projected pairs of quasars with z>2 and sub-arcminute separations. In these extremely rare sightlines, Ly(alpha) absorption, as measured in the \emphbackground quasar spectrum, can be used to study the environment, emission geometry, and radiative history of the \emphforeground quasar, provided that the systemic redshift of the foreground quasar is known accurately. We propose to obtain low dispersion (R~ 1700) H- band spectra of 24 sub-arcminute z > 2 projected pairs of quasars, with NIRI and GNIRS to determine systemic redshifts from the narrow [OIII] (lambda) 5008 emission line accurate to <100\rm km s^-1. This will eliminate the current ~ 5 \hmpc uncertainty in the foreground quasars' radial position, resolving transverse length scales as small as ~ 25\hkpc. We will then be able to characterize the transverse proximity effect, measure the cross-correlation function of quasars with neutral gas, constrain the isotropy of quasar emission, and the emission history of the quasars on timescales from 8 \times 10^4 to 3 \times 10^6 years, as well as gain insights into the fluorescent recombination radiation emitted by Lyman limit systems illuminated by ultraviolet photons.


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



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