Top panel: the light curve of ﹩0.1\lt \ {E}_{\gamma }\ \lt 500\,\mathrm{GeV}﹩ γ-rays from NGC 1275 from 2008 August 4 to 2017 March 5, with 3 day (blue) binning. Middle panels: sub intervals covering F1 (left) and F2 (right). F1 is shown with 8 hr (blue) and 12 hr (red) time intervals and F2 with 3 hr (blue) and 6 hr (red) bins. The red dashed lines show the fit of F1 and F2 with Equation (1). Lower panels: the plot of Npred/﹩\sqrt{\mathrm{Npred}}﹩ vs. Flux/﹩{\rm{\Delta }}\mathrm{Flux}﹩ for 8 hr (left) and 3 hr (right) bins.