Significance of the cross-correlation detection. Right panel: difference between the aligned CCF distributions “in-trail” (red-line) and “out-of-trail” (black-line) for the derived K_P. The two distributions are normalized and the error bars correspond to the square-root of the bin occurrences. The in-trail distribution is centered to higher values than the out-of-trail distribution with a 5.3 σ confidence level. Left panel: results of the Welch t-test performed for the same range of v_rest and K_P as before.