Distant star forming galaxies , next generation radio telescopes and the radio universe before re - ionisation

I present the various capabilities of upgraded and next generation radio telescopes, in particular their ability to detect and image distant star forming galaxies. I demonstrate that e-MERLIN, EVLA and LOFAR can detect systems similar to Arp 220 out to cosmological distances. The SKA can detect such systems out to any reasonable redshift that they might be expected to exist. Employing very long integration times on the multiple-beam SKA will require the array to be extended beyond the current specification-simply to avoid confusion noise limitations at 1.4 GHz. Other arguements for extending the SKA baseline length are also presented. As well as going " deeper " all these instruments (especially LOFAR and the SKA) will also go " wider "-detecting many tens of thousands of galaxies in a single day's observing. I briefly comment on the prospects of detecting radio emission at much earlier epochs, just before the epoch of re-ionisation.