Top panel: synchrotron and IC SEDs for the compression phase φ_obs = 0, 30, and 90°, and χ_B = 10^-3. The thin lines represent the emission without taking into account gamma-ray absorption due to electron-positron pair creation, i.e. the production SED. Middle panel: the same as for the top panel but for χ_B = 1. Bottom panel: a comparison between the SEDs of the compression and disruption phases.