Variation of L_median (in erg s⁻¹) with z for small redshifts and comparison with simulated and observed data. F_th is in units of erg cm⁻² s⁻¹. The plots in the panel a correspond to F_th = 2 × 10⁻⁸. The plots in panel b correspond to F_th = 1 × 10⁻⁷. The values of the spectral index α are marked on each curve. The orange dots are for simulated data. The larger dots correspond to the observed data for long, short, and ultralong GRBs (Goldstein et al. 2017; Cano et al. 2017; Michałowski et al. 2018; Gehrels et al. 2006; D’Avanzo et al. 2014; Demianski et al. 2017). The green dots are for short GRBs with monotonic afterglow, magenta dots for long GRBs with unavailable afterglow data, and the yellow dots correspond to ultralong GRBs with monotonic afterglow data.