Nanjing Univ, Dept Astron, Nanjing 210093, Peoples R China
; Chinese Acad Sci, Inst High Energy Phys, Lab Cosm Ray & High Energy Astrophys, Beijing 100039, Peoples R China
Conventional dynamic model of gamma-ray burst remnants is found to be incorrect for adiabatic blastwaves during the non-relativistic phase. A new model is derived, which is shown to be correct for both radiative and adiabatic blastwaves during both ultra-relativistic and non-relativistic phases. Our model also takes the evolution of the radiative efficiency into account. The importance of the transition from the ultra-relativistic phase to the non-relativistic phase is stressed.