Sensitivity map showing the detection significance (σ) of the multidimensional GP approach as a function of period and semi-amplitude K of injected planets. The colour map indicates the detection significance computed from the periodogram of the residuals. The 5σ detection contours are shown for the serial GP (dotted grey line), the composite or semi-shared GP (dashed grey line), and the multidimensional GP (solid grey line). Known planets are marked with yellow symbols. The vertical orange lines indicate the stellar rotation period and its first harmonic. The 16-day signal is recovered with a detection significance of 4.05σ using the multidimensional GP, 1.10σ using the composite GP and 0σ with the serial GP.