25 March 2008 case. Top: typical time series of the relative intensity at a fixed slit position. The approximate window size of the equivalent weighted running average to obtain the background is 22 min (left) and 96 min (right). Bottom colored panels: wavelet power spectrum. The hatched area is below the 95% confidence-level line, and the related data are not reliable. The time-integrated total power (normalized) versus time in minutes is shown to the right of the colored panels. Note that the maximum power peak occurs at a period of  ~16 min (left) and  ~64 min (right).