Image: This artist’s concept shows the “naked-eye” GRB close up. Observations suggest material shot outward in a two-component jet (white and green beams). Credit: NASA/Swift/Mary Pat Hrybyk-Keith and John Jones.
Posted on 09/10/2008 4:42:43 PM PDT by LibWhacker
A massive gamma-ray burst detected last March, believed to be the brightest ever seen, turns out to have been aimed directly at the Earth. A narrow jet that drove material toward us at 99.99995 of the speed of light is revealed in the data, itself wrapped within a somewhat slower and wider jet. The best estimates are that an alignment like this occurs only once every ten years. Says Paul O’Brien (University of Leicester, and a member of the team working on the Swift satellite):
“We normally detect only the wide jet of a GRB as the inner jet is very narrow, equivalent to not much more than 1/100th the angular size of the full Moon. It seems that to see a very bright GRB the narrow jet has to be pointing precisely at the Earth. We would expect that to happen only about once per decade. On March 19th, we got lucky.”
It could be said that any information we get about GRBs is in a sense lucky, given how tricky are the constraints for observing them. And indeed, another GRB just degrees away from this one was already under observation when the big blast went off, making it hard to miss. But wherever the GRB, the Swift satellite is making it possible to gather data from it, finding the original explosion and quickly alerting optical telescopes on Earth — so that they can begin observing within minutes. In this case, the blast was so intense that it temporarily blinded Swift’s X-Ray Telescope and UltraViolet/Optical Telescope, and its visible light was quickly being examined by wide-field cameras in Chile.
Image: This artist’s concept shows the “naked-eye” GRB close up. Observations suggest material shot outward in a two-component jet (white and green beams). Credit: NASA/Swift/Mary Pat Hrybyk-Keith and John Jones.
All of this gives us the opportunity to study a GRB from gamma-ray to radio wavelengths, examining what happened to one massive star that exhausted its fuel. GRB 080319B seized the attention of the world when it became clear that the burst was actually bright enough to be visible to the unaided eye, cresting at a magnitude of 5.3 even though the star that spawned it was located over 7.5 billion light years away. The bright afterglow is the result of the gas jets muscling out from the collapsing stellar core, striking gas the star had previously shed and heating it.
The paper is Racusin et al., “GRB 080319B: A Naked-Eye Stellar Blast from the Distant Universe,” slated for publication in Nature tomorrow and available here.
Addendum: Interesting comment by Alex Filippenko (UC Berkeley) in a just arrived news release (not yet up on the Berkeley site): If the supernova that produced this GRB were located 6000 light years from us, the event would have appeared as bright as the Sun. Filippenko calls it “…the most powerful event ever seen in human existence.”
I wonder if it's related....
Gamma rays are photons. They travel at exactly the speed of light, not 99.99995% of the speed of light, or 99.99999995% of the speed of light.
IT'S A SIGNAL!!!
*Or was, roughly 7.5 billion years ago...
I think I saw her in bed with Kirk on a star trek episode!
But not the speed of light... asymptotic.
Hey, watch the insults!
:)
"Where's the Ka-Boom? There was supposed to be an Earth-shattering Ka-Boom!"
Your suspicions would be right, I can no longer find the one that is in color.
Barack Obama: “And, and, and the gamma....ray burst, er, that you know...or let me just say, er, er, that, that, you know, this this this ....burst, and like I’ve always said, er, er, is....not good...for this, er, er, you know, country.”
“Use the Force, Luke. Use the Force.”
A ping. At twice the speed of light.
(Now, how did they aim this death gamma ray gamma shooter 7.5 billion years ago to arrive now (7.5 billion years after they shot the death ray gamma shooter), when they couldn’t take an observation on where we are now then if they were where they were when they were 7.5 billion years ago to shoot the death gamma ray 7.5 billion years ago, because they wouldn’t know where we now until 7.5 billion years after they tried to spot us 15 billion years ago when neither of us was where we are now to shoot the death ray gamma shooter?.)
If it had been as close as the Andromeda Galaxy (1.5 million LT) it would have been more than one billion times as bright, somewhere between the Sun and the Moon.
Of course, one would expect these things to be distributed with a density inversely proportional to the square of the distance, or iow, the relative frequency of occurance is inversely proportional to the relative brightness. (Relative brightness goes as one-on-R-square, volume per unit range goes as R-square.)
If it had been on the further edge of the Milky Way, it would be as bright as the sun.
Dead people. They're leaving the cemetery and boogieing to the polls.
I was wondering if it might have come from the Neutral Zone.
That explains those hot flashes I had back in March.
LOL!
Good thing they didn’t turn on that Large Hadron Collider at the same time last March.....
Go into town and round up a posse! They’re shootin’ at us!
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