Thermal and non-thermal emission from a variable outflow – magnetic reconnection framework. In each panel we show a sequence of thermal (red) and non-thermal (blue), spectra (the source redshift is z = 1). The Lorentz factor distribution adopted for the calculation of the thermal emission is the same as in Fig. 2 (left panel) or the same but with Γ divided by 2 (right panel). The thermal emission is computed using the formalism developed in Sect. 2.2, using five values of ϵ_th: 0.01, 0.03, 0.10, 0.30, and 0.5. The non-thermal spectrum is simply parametrised by a Band function, with the peak energy being given by the Amati relation (see text) and using five values of the efficiency of the magnetic reconnection, f_rec = f_Nth(1 + σ)/σ: 0.01, 0.03, 0.10, 0.30, and 0.5. In all cases, the isotropic magnetic power at the photosphere is fixed to σĖ_iso/(1 + σ) = 10⁵³   erg  s^-1. Finally, the magnetisation σ at large distance is either σ = 1 (solid lines) or 10 (dashed lines).