2013ApJ...770....8K

Metal-poor massive stars typically end their lives as blue supergiants (BSGs). Gamma-ray bursts (GRBs) from such progenitors could have an ultra-long duration of relativistic jets. For example, Population III (Pop III) GRBs at z ∼ 10-20 might be observable as X-ray-rich events with a typical duration of T₉₀∼ 10⁴(1 + z) s. The recent GRB111209A at z = 0.677 has an ultra-long duration of T₉₀∼ 2.5x10⁴ s and it has been suggested that its progenitor might have been a metal-poor BSG in the local universe. Here, we suggest that luminous UV/optical/infrared emission is associated with this new class of GRBs from metal-poor BSGs. Before the jet head breaks out of the progenitor envelope, the energy injected by the jet is stored in a hot plasma cocoon, which finally emerges and expands as a baryon-loaded fireball. We show that the photospheric emissions from the cocoon fireball could be intrinsically very bright (L_peak∼ 10⁴²-10⁴⁴ erg/s) in UV/optical bands (ε_peak ∼ 10 eV) with a typical duration of ∼100 days in the rest frame. Such cocoon emissions from Pop III GRBs might be detectable in infrared bands at ∼years after Pop III GRBs at up to z ∼ 15 by upcoming facilities such as the James Webb Space Telescope. We also suggest that GRB111209A might have been rebrightening in UV/optical bands up to an AB magnitude of ≲ 26. The cocoon emission from local metal-poor BSGs might have been observed previously as luminous supernovae without GRBs since they can be seen from the off-axis direction of the jet.