MIPS 24 Micron Observations of the Hubble Deep Field South: Probing the
  IR-Radio Correlation of Galaxies at z > 1
  We present MIPS 24 micron observations of the Hubble Deep Field South taken
with the Spitzer Space Telescope. The resulting image is 254 arcmin^2 in size
and has a sensitivity ranging between ~12 to ~30 microJy rms, with a median
sensitivity of ~20 microJy rms. A total of 495 sources have been cataloged with
a signal-to-noise ratio greater than 5 sigma. The source catalog is presented
as well as source counts which have been corrected for completeness and flux
boosting. The IR sources are then combined with MUSYC optical/NIR and ATHDFS
radio observations to obtain redshifts and radio flux densities of the sample.
We use the IR/radio flux density ratio (q_24) to explore the IR-radio
correlation for this IR sample and find q_24 = 0.71 +- 0.31 for sources
detected in both IR and radio. The results are extended by stacking IR sources
not detected in the radio observations and we derive an average q_24 for
redshift bins between 0 < z < 2.5. We find the high redshift (z > 1) sources
have an average q_{24} ratio which is better fit by local LIRG SEDs rather than
local ULIRG SEDs, indicating that high redshift ULIRGs differ in their IR/radio
properties. So ULIRGs at high redshift have SEDs different from those found
locally. Infrared faint radio sources are examined, and while nine radio
sources do not have a MIPS detection and are therefore radio-loud AGN, only one
radio source has an extreme IRAC 3.6 micron to radio flux density ratio
indicating it is a radio-loud AGN at z > 1.
