SIMBAD references

The physical origins of gamma-ray burst (GRB) prompt emission (photosphere or synchrotron) are still subject to debate, after more than five decades. Here, we find that many of the observed characteristics of 15 long GRBs, which have the highest prompt emission efficiency ϵ_γ (ϵ_γ ≳ 80%), strongly support photosphere (thermal) emission origin, in the following ways: (1) the relation between E_p and E_iso is almost ${E}_{{\rm{p}}}\propto {({E}_{\mathrm{iso}})}^{1/4}$ and the dispersion is quite small; (2) the simple power-law shape of the X-ray afterglow light curves and the presence of significant reverse shock signals in the optical afterglow light curves; (3) the best fits using the cutoff power-law model for time-integrated spectra; and (4) the consistent efficiency from observations (with E_iso/E_k) and the predictions from the photosphere emission model (with η/Γ). We then further investigate the characteristics of the long GRBs for two distinguished samples (ϵ_γ ≳ 50% and ϵ_γ ≲ 50%). It is found that the different distributions for E_p and E_iso, and the similar observed efficiency (from the X-ray afterglow) and theoretically predicted efficiency (from the prompt emission or the optical afterglow), follow the predictions of the photosphere emission model well. Also, based on the same efficiency, we derive an excellent correlation of ${\rm{\Gamma }}\propto {E}_{\mathrm{iso}}^{1/8}{E}_{{\rm{p}}}^{1/2}/{\left({T}_{90}\right)}^{1/4}$ to estimate Γ. Finally, we show that different distributions for E_p and E_iso, and the consistent efficiency, exist for short GRBs. We also give a natural explanation of the extended emission (ϵ_γ ≲ 50%) and the main pulse (ϵ_γ ≳ 50%).