  The ubiquitous and tight correlation between the radio continuum emission and
the far-infrared emission is also found to hold true for starburst galaxies and
Ultra Luminous Infrared Galaxies wherein most of the emission is from compact
structures. The infrared photon density in the cores is high enough for the
inverse Compton scattering to dominate over the synchrotron emission thus
spoiling the correlation. The high magnetic field postulated to avoid this,
also encounters the problem of steep radio index that is not observed. Further,
at high densities the flux of secondary electrons can exceed that of the
primary. The problems posed by such effects are discussed and suggestion for
further work made.
