Fig. 5: Simulated Δχ² distribution.

Δχ² is the statistical difference in the goodness-of-fit between the models Band and Band+Gaussian. The Panels a, b, c, d, and e show the probability distribution function (PDF) of Δχ² values obtained from 1 × 10⁷ simulations for time intervals 8 − 30 s, 8 − 21 s, 11 − 24 s, 14 − 27 s, 17 − 30 s, respectively. The red dashed line represents the observed Δχ² value. The p-\({{{\rm{value}}}}_{{{\rm{sim}}}}\) is the chance probability value obtained from 1.00 × 10⁷ simulations. If after N simulations no Δχ² value exceeds the actual fitting result, we report p-\({{{\rm{value}}}}_{{{\rm{sim}}}}\, < 1/N\). Source data are provided as a Source Data file.