Thermal Components in Gamma-ray Bursts. II. Constraining the Hybrid Jet Model

Understand

In explaining the physical origin of the jet composition of gamma-ray bursts (GRBs), a more general picture, i.e.

• the hybrid jet model (which introduced another magnetization parameter $\sigma_{0}$ on the basis of the traditional fireball model), has been well studied in Gao \& Zhang.
• However, it still has not yet been applied to a large GRB sample.
• Here, we first employ the "top-down" approach of Gao \& Zhang to diagnose the photosphere properties at the central engine to see how the hybrid model can account for the observed data as well, through applying a {\it Fermi} GRB sample (eight bursts) with the detected photosphere component, as presented in Li (our Paper I).