2016ApJ...823...83M

Supermassive black holes observed at high redshift z\gtrsim 6 could grow from direct collapse black holes (DCBHs) with masses ∼{10}^{5}{M}_☉ , which result from the collapse of supermassive stars (SMSs). If a relativistic jet is launched from a DCBH, then it can break out of the collapsing SMS and produce a gamma-ray burst (GRB). Although most GRB jets are off-axis from our line of sight, we show that the energy injected from the jet into a cocoon is huge ∼{10}^{55-56} erg , so that the cocoon fireball is observed as an ultra-luminous supernova of ∼{10}^{{45–46} erg {s}}{-1} for ∼5000[(1+z)/16] days . They will be detectable by future telescopes with near-infrared bands, such as Euclid, WFIRST, WISH, and JWST up to z∼20 and \lesssim 10 events per year, providing direct evidence of the DCBH scenario.