Same as Fig. 2 except with the x-axis rescaled as L_X/L_crit and the y-axis rescaled as E_cyc/E_∗. The values of E_∗ and L_crit used for each source are listed in Table 2. The solid curves associated with each group of data represent the theoretical predictions for the variation of the CRSF energy E_cyc as a function of L_X for each source, computed using Eq. (58), with the emission height h evaluated using Eq. (40) for the supercritical sources and Eq. (51) for the subcritical sources.