Long Duration X-Ray Flash and X-Ray Rich Gamma Ray Burst from Low Mass Population III Star

TL;DR

This paper predicts that low-mass Population III stars can produce long-duration, X-ray rich gamma-ray bursts with specific observational signatures, and discusses their detectability by future space missions at high redshifts.

Contribution

It demonstrates that low-mass Pop III stars can generate observable GRBs with unique durations and spectra, expanding the understanding of early universe high-energy phenomena.

Findings

Pop III GRBs have durations of ~10^5 seconds.

Peak luminosity of Pop III GRBs is ~5 x 10^{50} erg/sec.

Detectability of Pop III GRBs depends on spectral correlations and redshift.

Abstract

Recent numerical simulations suggest that Population III (Pop III) stars were born with masses not larger than $\sim 100 M_{\odot}$ but typically $\sim 40M_{\odot}$. 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 super giant star has the possibility to raise a gamma-ray burst (GRB) even though it keeps a massive hydrogen envelope. We evaluate observational characters of Pop III GRBs and predict that Pop III GRBs have the duration of $\sim 10^5$ sec in the observer frame and the peak luminosity of $\sim 5 \times 10^{50} {\rm erg} {\rm sec}^{-1}$. Assuming that the $E_p-L_p$ (or $E_p-E_{\gamma, \rm iso}$) correlation holds for Pop III GRBs, we find that the spectrum peak energy falls $\sim$ a few keV (or $\sim 100$ keV) in the observer frame. We discuss the detectability of Pop III GRBs by future satellite missions such as EXIST and Lobster. If the $E_p-E_{\gamma, \rm iso}$ correlation holds, we have the possibility to detect Pop III GRBs at $z \sim 9$ as long duration X-ray rich GRBs by EXIST. On the other hand, if the $E_p-L_p$ correlation holds, we have the possibility to detect Pop III GRBs up to $z \sim 19$ as long duration X-ray flashes by Lobster.