Scatter plots of C_p with MC propagation and expansion speeds for all the events listed in Table A.1. The top panel is the scatter plot between C_p (Eq. (10) and the MC propagation speed (⟨v⟩_MC). The correlation coefficient between C_p and ⟨v⟩_MC is r = 0.18, with p = 2 × 10⁻² (for BG1) and r = 0.15, with p = 5 × 10⁻² (for BG2). The equation of the fitted lines corresponding to BG1 and BG2 are y = 0.01x − 0.004 and y = 0.01x − 0.1, respectively. The middle panel is the scatter plot between C_p and the MC expansion speed (v_exp), only for events with v_exp >  0. The correlation coefficients are r = 0.25, with p = 2 × 10⁻³ for BG1 and r = 0.25, with p = 5 × 10⁻³ for BG2. The equation of the fitted lines are y = 0.05x + 4.5 and y = 0.05x + 3.26, for BG1 and BG2, respectively. The bottom panel is the scatter plot between C_p and v_exp/⟨v⟩_MC, only for events with v_exp >  0. The correlation coefficients are r = 0.23, with p = 6 × 10⁻³ (for BG1) and r = 0.22, with p = 10⁻³ (for BG2). The equation of the fitted lines are y = 25.3x + 4.30 (for BG1) and y = 25.78x + 3.02 (for BG2). The small p-values indicate a sufficiently high statistical confidence in estimating the r values for all three cases.