GLS power of the X-ray flux time series. The solid black line corresponds to the GLS power computed from the X-ray fluxes of set III defined in Sect. 2.3.2, the dashed green line corresponds to set I, and the dashed red line corresponds to setII. The solid cyan line shows the power of the GLS for the TIGRE S_MWO measurements, which are observed in about the same time interval as the X-ray data. The dashed red line shows the 1% FAP level for the X-ray GLSs.