Background-subtracted EPIC/pn light curve of GJ 745 B (black) and light curve of the background (green), both with a bin size of 800 s (see Sect. 4.2.1). We also show the quiescent rate with its standard deviation (red dashed line and shade, respectively) that we adopted for the calculation of the flare energy as explained in Sect. 4.2.2. The light curve is shorter than the nominal exposure time due to high and variable background at the end of the observation.