Peak luminosity versus FWHM_min for the Swift/BAT sample split into nine redshift bins with constant logarithmic space in luminosity distance; blue dots correspond to Type-I GRBs, and red ones correspond to Type-II GRBs. Dashed cyan lines correspond to 90% and 50% detection efficiency (vertical bar). Gold dashed lines represent loci of constant isotropic-equivalent released energy (in erg) of each individual peak, approximately calculated as E_iso = L_p FWHM_min.