Oscillating positions (‘+’) after removing the background trend and its best-fitting result, shown in cyan (a). They are taken from the coronal loop at AIA 171 Å, as shown in Fig. 3. The magenta curve shows the HXR flux measured by ASO-S/HXI at 20–80 keV during 16:56–17:15 UT. Local light curve integrated over the flare region (indicated by the gold box in Fig. 2) in psaabands of AIA 1700 Å (black), 1600 Å (green), 171 Å (red), and 211 Å (orange), respectively (b). The Arabic and English numbers, as well as the dashed vertical lines outline these oscillating peaks.