Intensity fluctuations in diffuse and bright point regions. The two left panels show the zoomed-in FOV covering the diffuse region (panel i) and bright point (panel ii) outlined by the cyan and orange boxes in Fig. 1b, respectively. Each image is the same time-averaged and normalized figure as shown in Fig. 1b, except the intensity range shown is further limited to the minimum and maximum for each zoomed-in FOV. Within the regions of interest, four smaller sub-fields a to d are outlined. Each of these boxes has the same area. The spatially averaged relative (left y-axis) and absolute (right y-axis) intensities for the respective sub-fields are plotted as a function of time on the right in panels a–d. The vertical bars shown in each of these panels represent the maximum error for each time series (see Appendix A).