First panel: periodogram of the simulated time series before correction (all points except for a 4 month gap), for a σ₀ of 10 cm/s. From second to fifth panel: same after correction using method 1 and the set of lines S₁, respectively for a σ₀ of 10 cm/s, 20 cm/s, 50 cm/s, and 1 m/s. The horizontal lines show the false alarm probability (fap) at 1% (dashed lines) and 10% (solid lines).