  Our current understanding of ultraluminous infrared galaxies suggest that
they are recent galaxy mergers in which much of the gas in the former spiral
disks, particularly that located at distances less than 5 kpc from each of the
pre-merger nuclei, has fallen into a common center, triggering a huge starburst
phenomenon. This large nuclear concentration of molecular gas has been detected
by many groups, and estimates of molecular mass and density have been made. Not
surprisingly, these estimates were found to be orders of magnitude larger than
the corresponding values found in our Galaxy. In this paper, a self-consistent
model of the high energy emission of the super-starburst galaxy Arp 220 is
presented. The model also provides an estimate of the radio emission from each
of the components of the central region of the galaxy (western and eastern
extreme starbursts, and molecular disk). The predicted radio spectrum is found
as a result of the synchrotron and free-free emission, and absorption, of the
primary and secondary steady population of electrons and positrons. The latter
is output of charged pion decay and knock-on leptonic production, subject to a
full set of losses in the interstellar medium. The resulting radio spectrum is
in agreement with sub-arcsec radio observations, what allows to estimate the
magnetic field. In addition, the FIR emission is modeled with dust emissivity,
and the computed FIR photon density is used as a target for inverse Compton
process as well as to give account of losses in the $\gamma$-ray scape.
Bremsstrahlung emission and neutral pion decay are also computed, and the
$\gamma$-ray spectrum is finally predicted. Future possible observations with
GLAST, and the ground based Cherenkov telescopes are discussed.
