Spectra, in the ν–νL_ν representation, produced by a power law distribution of particles accounting for a luminosity of 10⁴³ erg s⁻¹ at 1 GHz. The adopted slope is n = 2.5. The solid lines show spectra produced by protons; the dashed lines represent the spectra produced by leptons. The different slopes are due to the different a value, controlling the amount of collimation of the radiation, and not to a differentslope of the electron distribution. The top panel gives examples for ρ = 10⁶ cm. The bottom panel shows examples for ρ = 10⁷ cm. Parameters, listed in Table 1, were found to minimize the required total energy. N₀ indicated in units of cm⁻³ and ρ in cm.