GLS periodograms of the SOPHIE and HARPS-N RV data. For each panel, the horizontal lines show the theoretical 10% (short-dashed line), 1% (long-dashed line), and 0.1% (dot-dashed line) false alarm probability levels. The vertical dashed lines mark the orbital frequencies of the transiting planet (f_b = 0.0547 d⁻¹) and of the signals detected in the RVs at 5.46 and 60 d. Panel a: Combined RV data corrected for an instrumental offset. Panel b: RV residuals following the subtraction of the signal of the transiting planet TOI-2141 b.