Power-law index Γ vs. flux in (ASM-cts s⁻¹). The best-fit line is given by the function Γ = (0.965 ± 0.002) + (0.015 ± 0.001) × ((ASM-cts s⁻¹) − 5.0). This function is valid for 35-day phases up to 0.16. The low Γ value measured in February 2019 (cycle 494, see Table 2) was not included in this fit because the observation took place at a 35-day phase of 0.202, at which a lower value is expected (see text). The Pearson linear correlation coefficient is 0.53.