Distribution of count rates obtained from the background-subtracted EPIC light curve (Fig. 4), binned with a time resolution of 50 s. A potential “transition” threshold between high and low modes is indicated by a dashed orange line. Negative count rates can occur in bins where the source signal is very low or absent and the background dominates, as a result of the background subtraction. The upper panels display the Kernel Density Estimation curve, providing a smoothed representation of the count rate distribution.