Figure 22.

A test of our pattern-speed determination algorithms using the Prometheus 8:7 wave in the inner A ring. (a) The RMS phase difference residuals as a function of pattern speed assuming the pattern has an m = 8, as expected for this wave. The dashed line marks the predicted pattern speed for this pattern, while the dotted line marks the pattern speed that gives the minimum variance (in this case, these two lines are almost on top of each other). (b) The residuals in the phase differences from this best-fit solution as a function of time difference between the pairs of observations. The scatter in these data likely represents residual geometrical uncertainties in the various profiles. Figure from Hedman & Nicholson [4].