Gamma-ray spectra of EIC emission for a burst with GRB 090902B-like afterglow parameters, at T = 10 ^2.6 s (thin) and T = 10 ^3.6 s (thick). For comparison, synchrotron and SSC emission from the standard afterglow component are also shown. The source redshift is set to z = 1. Relevant parameters for the late jet are L ^b _LP| _{T′ a} = 1.02 × 10 ⁵⁰ erg s ⁻¹, T′ _a = 10 ³ s, E′ ^b = 0.1 keV, α _fl = 0, and α _st = 2. Relevant parameters for the standard afterglow component are , _ef = 0.15, _Bf = 0.058, n = 5.8 × 10 ⁻⁴ cm ⁻³, and p = 2.22. The attenuation by pair creation both inside and outside the source is taken into account.