Top panels: curvature emissivity as a function of frequency ν for different γ (labelled) and for two values of the emission angle ψ, 0.125^∘ (left column) and 5^∘ (right column). We can see that at large ψ the emission at high frequencies is quenched, but that the emissivity at larger γ is always greater than the emissivity at lower γ. Bottom panels: the same, multiplied by the phase space factor γp, for the synchrotron case. Contrary to the curvature case, for large γ the emissivity can be smaller than the one at lower γ. A magnetic field B = 1 G was considered in calculations for comparison.