Spitzer Space Telescope - General Observer Proposal #60158


Two Lensed Ly-A Emitters at z ~ 5

Principal Investigator: Michael Gladders
           Institution: University of Chicago

     Technical Contact: Michael Gladders, University of Chicago

Co-Investigators: 
Eva Wuyts, University of Chicago                                      
Benjamin Koester, University of Chicago                               
Matthew Bayliss, University of Chicago                                
Keren Sharon, University of Chicago                                   
Joseph Hennawi, University of California, Berkeley                    
Masamune Oguri, Stanford University                                   

Science Category: high-z galaxies (z>0.5) 
 Observing Modes: IRAC Post-Cryo Mapping
  Hours Approved: 1.8 

Abstract:
We propose 3.6 micron imaging of two newly discovered Ly-A emitters at z=5.0
and 5.2. These spectroscopically confirmed sources, located behind a pair of
strong lensing clusters from the SDSS Giant Arcs Survey, are lensed and appear
an order of magnitude brighter than the small samples of typical Ly-A emitters
previously found at high redshifts in ultra-deep fields. As such they offer the
opportunity for detailed individual study which these other sources do not, and
can be well measured in modest (less than 1 hour) total integrations. The
proposed observation provides a critical measure of the presence or absence of
older stars in these objects, and hence helps constrain stellar mass, and in
conjunction with ground-based near-IR imaging will yield a detailed picture of
the spectral energy distribution of these sources from rest-frame UV to optical
wavelengths.