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.”
The Emperor Ming: Klytus, I’m bored. What play thing can you offer me today?
Klytus: An obscure body in the S-K System, your majesty. The inhabitants refer to it as the planet Earth.
Klytus: Most effective, Your Majesty. Will you destroy this Earth?
The Emperor Ming: Later. I like to play with things a while before annihilation.
Munson: Dr. Zarkov! There’s no sun! It’s 8:24 in the morning, and there’s no sun!
Doctor Hans Zarkov: What do you find? The moon out of orbit?
Munson: By more than 12 degrees. This must be some sort of mistake.
Doctor Hans Zarkov: No, it’s no mistake... IT’S AN ATTACK! I’ve been right all these years!
That’s correct. But they’re not talking about the gamma rays in that sentence. They’re talking about “material;” i.e., physical matter. The gamma rays arrived here in March. The matter is still 3,750 light years away and headed this way at 99.99995% the speed of light. Never fear, however, by the time it arrives, the Earth will have moved on. I doubt it would hurt us even if we were still here, being just another attenuated blast of cosmic rays originating in deep space, which we are bombarded with every day.
I think your interociter needs a tuneup.
No doubt a blast from a Q-36 Illudium Space Modulator.
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As I understand it - these gamma ray bursts have a nasty reaction when they encounter botox.
Nancy Pelosi was last seen lining her house with lead.
Nice pic. I hate it when that happens!
So BushCheney shot at us 3 billion years before our solar system even existed and scored a direct hit! Sounds like Cheney’s targeting has improved . . . or deteriorated . . . or improved . . . . Oh, heck, maybe it was a gamma ray shotgun and there are a bunch of fried lawyers in nearby galaxies.
Nahhh, she liked him but he didn’t like her. She was sort of, you know....crazy!
susie
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