Comparison between the distribution of cross-correlation values far away from the planet radial velocity (out-of-trail, red), a Gaussian distribution with the same mean and variance (dashed red line), and the distribution of the cross-correlation values near the planet radial velocities (in-trail, blue). The out-of-trail distribution follows the Gaussian distribution down to approximately 4σ. If the transmission signal of the planet were detected, both distributions would show significantly different means, as it is the case.