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Above some frequency this flat spectral component should break to an optically thin spectrum ( α ~ -0.6 ) corresponding to the point at which the entire jet becomes transparent ; i.e. emission at the break frequency arises primarily from the ` base ' of the jet . The diffuse emission around these jets provides direct evidence of the interaction between the relativistic flows and the surrounding medium . Further , we proposed limits on emissions outside the bands of operation . Regardless of the attenuation levels shown above , we will not require emissions outside the frequency range of operation to be attenuated below the general radiated emission limits in Section 15.209 of our rules . A brightening of the X-ray emission at the north pole was associated with the impact of two comet fragments ( near the south pole ) . Fluorescence emission by the specimen ( primarily red wavelengths ) , which results from the green light excitation , is gathered by the objective and passes through the dichromatic mirror and barrier filter ( light above cut-off in Figure 2 ( c ) ) .