Spitzer Space Telescope - Directors Discretionary Time Proposal #280

IRS Spectroscopy of a Typical Lyman Break Galaxy

Principal Investigator: Richard Ellis 
Technical Contact: Brian Siana 
Institution: Caltech

Co-Investigators:
Johan Richard, Caltech
Harry Teplitz, Caltech
Iam Smail, Durham University
Jean-Paul Kneib, Caltech
Mark Swinbank, Durham University
Alastair Edge, Durham University
Harald Ebeling, Institute for Astronomy
Max Pettini, Cambridge University
   
Science Category: High-z Galaxies (z>0.5) 
Observing Modes: MIPS Phot, IRAC Mapping 
Hours Approved: 0.9 

Abstract:

We request Director's discretionary time on the Spitzer Space Telescope
(SST) to determine the restframe mid-infrared spectral properties of a
typical L* Lyman break galaxy (LBG) at z=3.07. Our proposed SST study of
this galaxy requests a total of 11 hrs integration: 2 hrs with IRAC and
MIPS at 24/70 microns to obtain photometry of the source at restframe
wavelengths of 0.8-17 microns and 9 hrs exposure with IRS in LL1/SL1 to
probe the 3-8 micron PAH and the shape of the continuum emission. This
study is only feasible because of a 30x boost to the light-gathering
power of Spitzer provided by a foreground gravitational lens - allowing
us to use these observations to address questions which are drivers of
the James Webb Space Telescope (JWST) science case: yielding insights
into the star formation properties of a normal, young galaxy seen 12
Gyrs ago.