Record-breaking X-ray blast briefly blinds space observatory

Jul 14, 2010 by Barbara K. Kennedy
Record-breaking X-ray blast briefly blinds space observatory
The brightest gamma-ray burst ever seen in X-rays temporarily blinded Swift's X-ray Telescope on 21 June 2010. This image merges the X-rays (red to yellow) with the same view from Swift's Ultraviolet/Optical Telescope, which showed nothing extraordinary. (The image is 5 arcminutes across.) Credit: NASA/Swift/Stefan Immler

A blast of the brightest X-rays ever detected from beyond our Milky Way galaxy's neighborhood temporarily blinded the X-ray eye on NASA's Swift space observatory earlier this summer, astronomers now report. The X-rays traveled through space for 5-billion years before slamming into and overwhelming Swift's X-ray Telescope on 21 June. The blindingly bright blast came from a gamma-ray burst, a violent eruption of energy from the explosion of a massive star morphing into a new black hole.

"This is by far the brightest light source ever seen in X-ray wavelengths at cosmological distances," said David Burrows, senior scientist and professor of astronomy and astrophysics at Penn State University and the lead scientist for Swift's X-ray Telescope (XRT).

Although the was designed specifically to study gamma-ray bursts, the instrument was not designed to handle an X-ray blast this bright. "The intensity of these X-rays was unexpected and unprecedented" said Neil Gehrels, Swift's principal investigator at NASA's Goddard Space Flight Center. He said the burst, named GRB 100621A, is the brightest X-ray source that Swift has detected since the observatory began X-ray observation in early 2005. "Just when we were beginning to think that we had seen everything that gamma-ray bursts could throw at us, this burst came along to challenge our assumptions about how powerful their X-ray emissions can be," Gehrels said.

"The burst was so bright when it first erupted that our data-analysis software shut down," said Phil Evans, a postdoctoral research assistant at the University of Leicester in the United Kingdom who wrote parts of Swift's X-ray-analysis software. "So many photons were bombarding the detector each second that it just couldn't count them quickly enough. It was like trying to use a rain gauge and a bucket to measure the flow rate of a tsunami."

The software soon resumed capturing the evolution of the burst over time, and Evans recovered the data that Swift had detected during the software's brief shutdown. The scientists then were able to measure the blast's X-ray brightness at 143,000 X-ray photons per second during its fleeting period of greatest brightness, which is more that 140 times brighter than the brightest continuous X-ray source in the sky -- a neutron star that is more than 500,000 times closer to Earth than the gamma-ray burst, and that sends a 'mere' 10,000 photons per second streaming toward Swift's telescopes.

Gamma-ray bursts typically begin with a bright flash of high-energy gamma-rays and X-rays, then fade away like a fireworks display, sometimes leaving behind a disappearing afterglow in less-energetic wavelengths, including optical and ultraviolet. Surprisingly, although the energy from this burst was the brightest ever in X-rays, it was merely ordinary in optical and ultraviolet wavelengths.

The Swift scientists were able to estimate the overall brightness of GRB 100621A by sampling the photons at some distance from its overexposed center -- a standard correction technique. Scientists who study the Sun use a similar approach to observe the Sun's corona by blocking out its much-brighter center. "With this burst, we had to sample the photons twice as far from the center as we ever had to go before," Burrows said. "The correction factor for the X-rays from GRB 100621A was 168 times larger than for a typical gamma-ray burst and 5 times larger than for the brightest burst we previously had seen. We never thought we'd see anything this bright."

Automated analysis of the Swift XRT data is performed at the University of Leicester in the United Kingdom, which has been studying X-rays from outer space for the past half century. Evans was the first to see the processed data from the burst's initial blast. "When I first saw the strange data from this burst, I knew that I had discovered something extraordinary," he said. "It was an indescribable feeling when I realized, at that moment, that I was the only person in the whole universe who knew that this extraordinary event had occurred. Now, after our analysis of the data, we know that this burst is one for the record books."

Explore further: How baryon acoustic oscillation reveals the expansion of the universe

More information: NASA's "Geeked on Goddard" blog has a related story about the GRB 100621A burst at geeked.gsfc.nasa.gov/?p=1417

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User comments : 12

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LariAnn
4.2 / 5 (11) Jul 14, 2010
"It was an indescribable feeling when I realized, at that moment, that I was the only person in the whole universe who knew that this extraordinary event had occurred."
Really? With so much space and time between us and the event, the odds are very good that someone else in the universe besides Evans knew about this, especially if they were close enough to it for damaging effects to manifest on their world, observatory, or spacecraft!
Sonhouse
4.5 / 5 (8) Jul 14, 2010
It might be a stretch to say 'I am the only person in the UNIVERSE who knew about this'. Since this event was at cosmological distances, it had to have swept through millions of galaxies on its way to Earth. I think it safe to say somewhere in those galaxies lies a civilization who also received that burst. That said, it is a heck of a discovery! Good work!
SteveL
4.2 / 5 (6) Jul 14, 2010
"The X-rays traveled through space for 5-billion years before slamming into and overwhelming Swift's X-ray Telescope on 21 June."

"It was an indescribable feeling when I realized, at that moment, that I was the only person in the whole universe who knew that this extraordinary event had occurred"

The only person within 10 billion light years (5 billion in just our direction). What an incredible waste of space. So lonely...

Ugh, eating lunch and posting - I was too slow. Seems several of us caught that.
jselin
4.8 / 5 (4) Jul 14, 2010
"It was an indescribable feeling when I realized, at that moment, that I was the only person in the whole universe who knew that this extraordinary event had occurred."

I'd have to disagree... the "locals" 5 billion years ago when this thing went off were probably quite aware a nearby star exploded. That is, if you believe life is abundant.

EDIT: Haha, wow too slow I guess. I like that 4 of us were all typing the same basic thing!
Ravenrant
1.8 / 5 (5) Jul 14, 2010
Actually his statement is correct, there probably wasn't anyone else who was alive at that time that knew about it.
frajo
3.4 / 5 (5) Jul 14, 2010
there probably wasn't anyone else who was alive at that time that knew about it.
How do you calculate this probability?
omatumr
2.1 / 5 (7) Jul 14, 2010
More important would be information on the energy source for the blast.

The US Department of Energy should know, or at least have some ideas.

The largest known sources of nuclear are:
Neutron Repulsion > Fusion > Fission
Journal of Fusion Energy 20 (2001) 197-201

With kind regards,
Oliver K. Manuel
Former NASA Principal
Investigator for Apollo
Ethelred
3.7 / 5 (7) Jul 15, 2010
Neutron Repulsion > Fusion > Fission


Nonexistent things can't be greater than Fusion or Fission or for that matter a lighter.

And a few you failed to mention. Matter anti-Matter, core collapse super-nova, stellar collisions, Neutron Star collisions. Oh yes how about a neutron star colliding with a black hole.

Ethelred
Hesperos
not rated yet Jul 15, 2010
Ok, a jet was pointed at the Solar System. Is that such a big deal? It could be if the source were 5 million instead of 5 billion light years away.
omatumr
3 / 5 (4) Jul 15, 2010
Please see the related news story and comments on PhysOrg, "Unravelling the Mystery of Massive Star Birth: All Stars are Born the Same Way"

With kind regards,
Oliver K. Manuel
Ethelred
4 / 5 (4) Jul 16, 2010
Please notice the total lack of any sign of a neutron star in that article.

How about you figure out just how often an iron atom is supposed to decay your hypothesis? Then see how big a stack of iron would be needed to see a decay in a reasonable length of time. Then compare it the experiment in India. Do the math first before you look please.

Ethelred
Modernmystic
1 / 5 (1) Jul 27, 2010
Didn't Luke blow that thing up?