Periodograms of the raw RVs (red) and of the residual RVs (blue) after removing the best GP plus 2-planet model to account for stellar signals and the 3.77 and 10.64-day planets present in the time series. The horizontal lines show from top to bottom the 0.1, 1 and 10% p-values used as a first guess to estimate signal significance. The non-white residuals suggest an imperfect model.