Fig. 4: Ratio of the prompt emission radius, RE and the photospheric radius, Rph versus total isotropic energy Eiso.
From: A wind environment and Lorentz factors of tens explain gamma-ray bursts X-ray plateau
Purple, black and blue points represent GRBs in the three different classes I, II, III respectively (see Supplementary Tables 1–3). The errors correspond to a significance of one sigma. The low luminous GRBs with lowest Lorentz factor (GRBs 060614, 060729, 100418A and 171205A) are marked by their names. For these GRBs we consider ϵB = 0.1, leading to typical initial jet Lorentz factor Γi ≈ 10 and ratio RE/Rph ~ 5 − 25, but for GRB 100418A, which is marginally consistent with RE/Rph ~ 1. For all other GRBs, we assume ϵB = 10−3 when making this plot, and a variability time \({{\Delta }}{t}_{\min }\) taken from Refs. 43, 44, except for GRB 060714, where Δt = 5 s is assumed based on data from the Swift-BAT light-curve. We point out that a higher value of ϵB increases this ratio. The vertical green lines associated to each GRB illustrate the possible ratios of RE/Rph obtained for magnetization in the range 10−3≤ϵB≤0.7. The horizontal red line indicates RE/Rph = 1. It shows that in all cases, sufficiently high value of ϵB within the examined range leads to RE > Rph. The source data to reproduce this figure are provided as a Source Data file.
