Comparison between the gamma-ray lightcurves obtained with the simplified prescription (solid curve) and the more detailed treatment (dashed curve; stars indicate the points where the luminosity was computed). We consider i = 60° and ζ_eq = 10⁻² for L_j = 10⁴³ and 10⁴⁴ erg s⁻¹, and i = 0° and ζ_eq = 10⁻⁶ for L_j = 10⁴⁶ erg s⁻¹. The vertical ticks indicate the moment the SN reaches 1 kpc (for L_j = 10⁴³ erg s⁻¹ this takes place at t_obs ∼ 1.8 × 10⁴ yr, hence it is not shown in the plot).