Reverse Shocks and The Optical Flash
There can be "reverse shocks", which propagate back into the shocked matter once it begins to encounter the interstellar medium. The twice-shocked material can produce a bright optical/UV flash, which has been seen in a few GRBs, though it appears not to be a common phenomenon.
Read more about this topic: Gamma-ray Burst Emission Mechanisms
Famous quotes containing the words reverse, shocks, optical and/or flash:
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