with a dust obscured AGN. Throughout this paper, we adopt a $\Omega_{M}=0.27$, $\Omega_{\Lambda}=0.73$, H$_{0}$=71 km s$^{-1}$ Mpc$^{-1}$ cosmology.

IRS Peak-Up Imaging of GOODS-S 
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The 16$\mu$m and 22$\mu$m observations were carried out using the peak-up imaging capability of the Infrared Spectrograph (IRS) instrument [@Houck:04] on the [[*Spitzer*]{}]{} [*Space Telescope*]{}. The field of view of the peak-up imaging camera is 54$\arcsec\times$80$\arcsec$. The central $\sim$130 arcmin$^{2}$ of the GOODS-S field was observed with 60s frame times. Most of the area within the GOODS fields had four dithers per position while the UDF area had 32 dithers per position. Each frame was distortion corrected and background subtracted. The dithered frames were combined using “drizzle” [@Fruchter]. Due to the limited number of dithers per position, point kernel drizzling, which would have minimized the correlated noise in the mosaics was not possible. The final mosaics have a plate scale of 0.9$\arcsec$ per pixel. The exposure time in the final mosaics is $\sim$4 min pix$^{-1}$ over most of the GOODS area while the UDF area was observed with 32 min pix$^{-1}$. JD2, although in the UDF region, seredipitously lies in a part of the coverage map where the exposure time is 68 min, twice that of 