Relation between ν_c, z and L_iso fit with the X-ray data of the bursts in our sample, represented by colored circles. The straight blue line represents the best-fit line from the linear fit, while the blue-shaded area shows the 3σ_sc scatter region of the relation. The relation has been extrapolated to higher energies, where GBM short GRB data are represented with green squares. GRB 211211A data are taken from Mei et al. (2025) and are represented with yellow stars.