A Shell Collision Scenario for EP251222b/GRB 251222A: Connecting Prompt Emission and Double-Peaked Afterglow
The study models GRB 251223A as a collision between two shells: a faster, narrower shell catching up to a slower, wider one. By fitting multi-wavelength afterglow data, the model yields Lorentz factors of ~293 and ~228 for the merged core and outer component. This collision scenario successfully reproduces the observed double-peaked afterglow morphology.