Evolution of energy flux (ø) during the lifetime of SNR for synchrotron emission and gamma-ray emission at specific energy ranges. Region 1, region 2, and region 3 denote the free wind, shocked wind, and shocked ISM region, respectively, which are distinguished by different colours. The brown shaded region around 3200 yr denotes the FS transition from the free wind to the shocked wind zone, and the blue shaded region around 20 000 yr denotes the interaction between FS and LBV shell.