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:
“They shall beat their swords into plowshares, and their spears into pruninghooks: nation shall not lift up sword against nation, neither shall they learn war any more.”
—Bible: Hebrew Isaiah, 2:4.
The words reappear in Micah 4:3, and the reverse injunction is made in Joel 3:10 (”Beat your plowshares into swords ...”)
“Vice, in its true light, is so deformed, that it shocks us at first sight; and would hardly ever seduce us, if it did not at first wear the mask of some virtue.”
—Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)
“The convent, which belongs to the West as it does to the East, to antiquity as it does to the present time, to Buddhism and Muhammadanism as it does to Christianity, is one of the optical devices whereby man gains a glimpse of infinity.”
—Victor Hugo (1802–1885)
“Here lies a man who was killed by lightning;
He died when his prospects seemed to be brightening.
He might have cut a flash in this world of trouble,
But the flash cut him, and he lies in the stubble.”
—Anonymous. From Booth, Epigrams Ancient and Modern (1863)