Correlations V–Ap, B–Ap, BV–Ap, and BV² − Ap. In panels b) − d) we separated the data points characterized by v > 450 km s^-1 (circles), from those having v < 450 km s^-1 (black dots). The linear least squares fit parameters, the correlation coefficient R, and the applied time lag Δt are presented in the insets; in panels b) − d), the fit parameters are for the v > 450 km s^-1 data (bold line). Dashed lines are fits for the v < 450 km s^-1 data; dotted lines represent an estimate of the upper limit.