Possible prompt emission of a GRB 170817A-like jet compared to archival SGRB data. The bottom and right-hand panels show respectively the isotropic-equivalent energy E_iso(θ_v) and the rest-frame SED peak photon energy E_p(θ_v) as functions of the viewing angle θ_v (red solid lines) for the best-fit jet structure of Ghirlanda et al. (2019), along with their uncertainty regions (1σ – orange; 2σ – yellow). In the top-left panel, the red solid line shows the corresponding track and uncertainty regions on the (E_iso, E_p) plane. The plots are joined to ease the determination of the viewing angle that corresponds to a given point on the (E_iso, E_p) track. The blue cross shows the observed properties of GRB 170817A, while black crosses show the SGRBs from our sample (Sect. 4.1). Cyan circles mark bursts which belong to the Type I Gold Sample in Z09, while green squares mark bursts that have f_NC ≥ 0.5 in the analysis of B13.