Mean of absolute running-difference XRT images, normalised by the average XRT image (Eq. (1)). Each image in the series is taken 3 min apart from the previous and the next. The blue contours are the supergranular lanes, from the 4-h averaged MDI flow field. The green and red contours (respectively) are the magnetic field strength at −10 G/+ 10 G from the 4 h-averaged MDI magnetogram. The white rectangle is the FOV of SOT (Fig. 6). The smaller white rectangle encompass the X-ray transients.