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:
“During the late war [the American Revolution] I had an infallible rule for deciding what [Great Britain] would do on every occasion. It was, to consider what they ought to do, and to take the reverse of that as what they would assuredly do, and I can say with truth that I was never deceived.”
—Thomas Jefferson (1743–1826)
“Slavery is founded on the selfishness of man’s nature—opposition to it on his love of justice. These principles are in eternal antagonism; and when brought into collision so fiercely as slavery extension brings them, shocks and throes and convulsions must ceaselessly follow.”
—Abraham Lincoln (1809–1865)
“People who have realized that this is a dream imagine that it is easy to wake up, and are angry with those who continue sleeping, not considering that the whole world that environs them does not permit them to wake. Life proceeds as a series of optical illusions, artificial needs and imaginary sensations.”
—Alexander Herzen (1812–1870)
“We cannot know how much we learn
From those who never will return,
Until a flash of unforeseen
Remembrance falls on what has been.”
—Edwin Arlington Robinson (1869–1935)