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April 10, 2003 Press Contact: Steve Koppes
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Astrophysicists scurry to make follow-up observations of ‘nearby’ cosmic explosion

The birth cry of a black hole has startled University of Chicago astrophysicists and their colleagues who operate a NASA satellite that searches for gamma-ray bursts, the most powerful explosions in the universe.

Now the Chicago astrophysicists are rushing to make follow-up observations of the event with the Astrophysical Research Consortium 3.5-meter telescope at the Apache Point Observatory in New Mexico. They also are drowning in information provided by amateur astronomers.

“This event is so bright that hundreds of amateur astronomers have been observing it, recording their data and providing it to us,” said Don Lamb Jr., the Louis Block Professor in Astronomy & Astrophysics at the University of Chicago and Mission Scientist for the HETE-2 mission. “We can’t keep up with it.”

Gamma-ray bursts signal the birth of black holes, which are objects so dense that no light can escape their gravitational pull. The burst detected by NASA’s High Energy Transient Explorer-2 satellite on the morning of March 29 was one of the brightest and closest every reliably documented, Lamb said.

“This could nail the connection between gamma-ray bursts and core-collapse supernovae,” he said. This type of supernova, or exploding star, results in the formation of a black hole.

The data suggest that the supernova explosion was very non-spherical, which supports new ideas about how core collapse supernovae happen. “This is absolutely going to change everything,” Lamb said.

The burst, designated GRB 030329, lasted for more than 30 seconds. Only two other gamma-ray bursts have shined more brightly in the 30 years since the phenomenon was discovered, Lamb said. Even its afterglow shined more than 10,000 times brighter than its host galaxy two hours after the burst occurred.

The explosion occurred approximately 2 billion light years from Earth, too distant to pose a threat, but two and a half times closer than the next-closest burst for which scientists have reliable measurements.

HETE-2 is pinpointing the positions on the sky of 25 gamma-ray bursts annually. “The chance of a burst this near and this bright happening is one in a few thousand,” Lamb said. “We likely won’t see anything like this again.”

Collaborating with Lamb on HETE-2 are the University of Chicago’s Carlo Graziani, Senior Research Associate in Astronomy & Astrophysics, and Timothy Donaghy, a graduate student in Physics. Collaborating with him on the follow-up observations are Donald York, the Horace B. Horton Professor in Astronomy & Astrophysics at the University of Chicago, and John Barentine and Russet McMillan, Observing Specialists at Apache Point Observatory.
Last modified at 02:42 PM CST on Friday, September 23, 2005.

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