Wavelet analysis results of detrended light curves obtained from slit 1 AIA 171 Å time-distance map for locations L1 (left) and L3 (right) (location given in Fig. 4). Top panel: variation of obtained detrended intensity with time. Bottom left panel: corresponding wavelet spectrum (high power density in blue). Bottom right panel: global wavelet power spectrum. The dashed lines indicate the maximum period detectable from wavelet analysis due to cone-of-influence, whereas the dotted line indicates 99% confidence level curve. Periods P1 and P2 of the first two global power peaks are printed at the top right. On the time axis, the time starts at 7:30 UT.