PI: Patrick Hall, Princeton University / P. U. Catolica de Chile, firstname.lastname@example.org
Address: Princeton University Observatory, Peyton Hall, Ivy Lane, Princeton, NJ 08544-1001, USA
CoI: Mike Gladders, OCIW
CoI: Howard Yee, U. of Toronto
CoI: Michael DeRobertis, York University
Title: Completing Infrared Confirmation of z>5.5 Quasar Candidates
Abstract: Gunn-Peterson troughs (neutral hydrogen absorption) have been discovered in the spectra of two quasars from the Sloan Digital Sky Survey at z=6.28 and z=6.4. The lack of such troughs in the six other known 5.5<z<6 quasars suggests that z~6 is the tail end of the reionization epoch, when the spheres of ionized hydrogen around quasars and star-forming galaxies finally overlap. To better determine the timescale over which reionization occurred - and how the distribution of neutral hydrogen evolved during that epoch - requires more quasars at z>5.5. We have in hand 90 deg^2 of CTIO and CFHT Rz imaging which enables us to select candidate z>5.5 quasars and L/T type stars and brown dwarfs as objects with very red (R-z)_AB colors. Here we propose a final semester of KPNO near-IR imaging to efficiently and accurately separate the quasars among our equatorial and northern candidates from the more numerous L and T dwarfs (which are scientifically interesting in their own right). Our survey reaches two magnitudes fainter than the SDSS, providing a tighter constraint on the quasar contribution to the UV flux needed for reionization (and enabling the discovery of more distant L and T dwarfs). The surface density of z>5.5 quasars is estimated to be 0.1 deg^-2 %unknown in the 20<z_AB<22 magnitude range of our survey, but could be as high as 1 deg^-2.
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