Correlations between L(t) and S_r, S_X, and S_γ. The solid lines represent the best linear fits (from left to right): log S_r = (1.78 ± 0.20)log L(t)−(36.89 ± 7.60), log S_X = (1.89 ± 0.32)log L(t)−(37.79 ± 12.42), and log S_γ = (0.71 ± 0.17)log L(t) + (5.89 ± 6.59); the correlation coefficients r = 0.91, 0.82, and 0.71; and the probability of the null hypothesis P_null = 1.24 × 10^-7,2.57 × 10^-5, and 9.05 × 10^-4, respectively. The dashed lines are the 2σ confidence bands for the sample.