Strong Extragalactic Radio Burst Poses a Mystery

Sometimes, what seems like a remarkable scientific discovery turns out to be an error in the data. And other times, it leads to a Nobel Prize. A new research paper in the new edition of the journal Science epitomizes that uncertainty.

Astronomers report seeing an extremely bright, extremely powerful radio burst from far outside of our galaxy. They can't recall seeing anything like it before — and they have no idea what caused it.

The story begins in 2001, when astronomers pointed the Parkes radio telescope in Australia at the Small Magellanic Cloud. The cloud is really a galaxy about 200,000 light years away. The astronomers were looking for pulsars, spinning neutron stars that pour out rhythmic bursts of energy.

After the survey was over, Duncan Lorimer of West Virginia University got hold of the data from the telescope. Just for fun, he started analyzing the data a different way, by screening out signals from relative close-in objects like the pulsars in the Magellanic cloud, and focusing instead on objects much farther away — as far as a billion light years away.

Lorimer asked an undergraduate, David Narkevic, to help him. This past winter, on one of their weekly meetings, Narkevic showed him a graph of data collected on August 24, 2001.

"When he showed me this, you know, it looks, it looks quite interesting," Lorimer said. "And I said, 'Yeah, you bet,' it's very interesting, we've never seen anything like this before."

The graph showed an extremely strong radio signal lasting approximately five thousandths of a second.

"So, we got very excited when we saw that," Lorimer said. "It is so bright, it jumps off the page."

Lorimer scoured the data for any other bursts from the same spot, but there were none. He checked to see if any other telescopes spotted something in that part of the sky at the same time as his radio pulse. Again, nothing.

So he is stuck with one remarkable event. But he predicts that a search through previous radio telescope surveys will turn up more.

"There should be a number of them also present in other archival surveys. And we're currently in the process of looking for those events," Lorimer said.

When asked about the case, Lorimer admits to uncertainty. Still, he said he hopes that "when the results are in-house, that it'll get people thinking about new types of phenomena."

And they have started to do just that. Brad Schaefer is an astronomer at Louisiana State University.

"This could be just a version of something we've already thought of," Schaefer said. "Or it could be something completely new that no one has any idea of what it could be, yet."

Schaefer says this is the kind of thing astronomers live for.

"It could be due to a black hole-neutron star collision," he said. "Or perhaps a neutron star-neutron star collision. Or perhaps even a black hole-black hole collision, far off in a distant galaxy. Well, a billion light years away."

While Schaefer may call the report "a wonderful event," others warn that it is not confirmed, and urge caution in studying it.

Donald Lamb, the director of the Center for Astrophysical Thermonuclear Flashes at the University of Chicago, says with only one event, the question lingers if the phenomenon really exists, or if it's just some hiccup in the equipment.

But if Lorimer's data is accurate, Lamb says, it is a real puzzle.

"I think it's so crazy an event it's going to take some time and some head-scratching to come up with an explanation of it," Lamb said.

Asked if he had a favorite speculation about the phenomenon, Lamb said, "I wish I did. If I would be, I might not be talking to you on the phone, I might be busily writing a paper."

The person who winds up writing that paper could be in line for a Nobel Prize. Or maybe not.

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