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We have obtained the deepest image of the radio sky ever obtained, using
190 hours of VLA time to reach an rms of 1.5 microJansky at 8.4GHz at a
resolution of 3 arcsec, of a field having exceptionally low cirrus confusion.
This image highlights the population of microJansky radio sources and
contains two quasars at z=2.561, possibly in a cluster giving rise to
a Sunyaev-Zeldovich effect observed in the radio data. HST data and optical
redshifts show that the microJansky radio sources are merger-induced
starbursts in luminous disk galaxies at significant redshifts (spectroscopic
redshifts are available out to z=0.7). This population is evolving strongly
and highlights the evolution of the galaxy population by the successive
hierachical merging of galaxies. We propose to obtain confusion-limited ISO
imaging with CAM at 15 and 6.7 micron and PHOT at 90 micron of this unique
field. These data will provide first determinations of the total star
formation rates in these objects, and hence of the star formation density in
this population, and the evolution thereof, independent of obscuration by
dust. Spectral energy distributions will elucidate the role of active nuclei.
Luminous, but optically obscured microJansky radio galaxies will be revealed
by the ISO data. The deep VLA field is a unique compendium of starforming
galaxies at significant redshifts, and given the natural connection with the
infrared regime through the radio-infrared relation, the ISO data will make
a unique contribution to the field of galaxy evolution with these data.