  The detection of Pop III supernovae could directly probe the primordial IMF
for the first time, unveiling the properties of the first galaxies, early
chemical enrichment and reionization, and the seeds of supermassive black
holes. Growing evidence that some Pop III stars were less massive than 100
solar masses may complicate prospects for their detection, because even though
they would have been more plentiful they would have died as core-collapse
supernovae, with far less luminosity than pair-instability explosions. This
picture greatly improves if the SN shock collides with a dense circumstellar
shell ejected during a prior violent LBV type eruption. Such collisions can
turn even dim SNe into extremely bright ones whose luminosities can rival those
of pair-instability SNe. We present simulations of Pop III Type IIn SN light
curves and spectra performed with the Los Alamos RAGE and SPECTRUM codes.
Taking into account Lyman-alpha absorption in the early universe and
cosmological redshifting, we find that 40 solar mass Pop III Type IIn SNe will
be visible out to z ~ 20 with JWST and out to z ~ 7 with WFIRST. Thus, even low
mass Pop III SNe can be used to probe the primeval universe.
