Spitzer Space Telescope - Archive Research Proposal #50622


Hunting for z'-dropout z > 6.5 Quasars in the SWIRE Legacy Fields

Principal Investigator: Gillian Wilson
           Institution: University of California Riverside

     Technical Contact: Gillian Wilson, University of California Riverside

Co-Investigators: 
Mark Lacy, Spitzer Science Center / Caltech                           
Jonathan Gardner, Goddard Space Flight Center                         
Howard Yee, University of Toronto                                     
Patrick Lowrance, Spitzer Science Center / Caltech                    
Adam Muzzin, Yale University                                          
Jason Surace, Spitzer Science Center / Caltech                        

Science Category: cosmology 
Dollars Approved: 100000 

Abstract:
A total of 13 quasars at 6 < z < 6.43 have been successfully detected by the
Sloan Digital Sky Survey (SDSS) and Canada-France High-z Quasar Survey (CFHQS)
using an i'-dropout technique. We propose to extend the search for quasars to z
> 6.5 by targeting z'-dropout sources using deep z-band imaging from the Spitzer
Adaptation of the Red-sequence Cluster Survey (SpARCS) combined with IR imaging
from the Spitzer SWIRE Legacy Survey. Extrapolation from the quasar luminosity
function suggests that there will be 13 quasars at z > 6, and 2 quasars at z > 8
within the 50 square degrees of the SpARCS/SWIRE fields that are brighter than
the SWIRE detection limit. Very high redshift quasars are required as targets
for The James Webb Space Telescopes's scientific goal of studying "The End of
the Dark Ages: First Light and Reionization", and the work proposed here would
develop techniques which could be applied to a Spitzer Warm Mission Survey for
high-redshift quasars. Successful detection of high redshift quasars will
require careful matching of the optical and Spitzer catalogs, efficient
star-galaxy separation, and extensive modelling of Spitzer colors to distinguish
as efficiently as possible between quasars and other extremely red optical-IR
"contaminating" sources e.g., cool stars and dusty galaxies. We also propose to
search for "Y" dwarfs, the coolest, and as yet undiscovered, class of brown
dwarf.