2012ApJ...759..128N

Recent numerical simulations suggest that Population III (Pop III) stars were born with masses not larger than ∼100 M_☉ and typically ∼40 M_☉. By self-consistently considering the jet generation and propagation in the envelope of these low-mass Pop III stars, we find that a Pop III blue supergiant star has the possibility of giving rise to a gamma-ray burst (GRB) even though it keeps a massive hydrogen envelope. We evaluate observational characteristics of Pop III GRBs and predict that Pop III GRBs have a duration of ∼10⁵ s in the observer frame and a peak luminosity of ∼5x10⁵⁰ erg/s. Assuming that the E_p-L_p(or E_p-E_γ, iso_) correlation holds for Pop III GRBs, we find that the spectrum peak energy falls at approximately a few keV (or ∼100 keV) in the observer frame. We discuss the detectability of Pop III GRBs by future satellite missions such as EXIST and Lobster. If the E_p-E_γ, iso_ correlation holds, we have the possibility to detect Pop III GRBs at z ∼ 9 as long-duration X-ray-rich GRBs by EXIST. Conversely, if the E_p-L_p correlation holds, we have the possibility to detect Pop III GRBs up to z ∼ 19 as long-duration X-ray flashes by Lobster.