MIT scientists and others arriving on the scene of a gamma-ray burst witnessed the death of a gigantic star and the birth of something monstrous in its place, possibly a brand-new, spinning black hole.
The observation, featured in the March 20 issue of Nature, is the most detailed of any gamma-ray burst to date and provides confirmation of the "collapsar model," in which the core of a supermassive star is thought to collapse into a black hole. The observation was made by NASA's High-Energy Transient Explorer (HETE), built by MIT; ground-based robotic telescopes and fast-acting researchers around the globe.
"If a gamma-ray burst is the birth cry of a black hole, then the HETE satellite has just allowed us into the delivery room," said Derek Fox of the California Institute of Technology, lead author of the Nature paper.
Gamma-ray bursts are as bright as a million trillion suns. The mysterious bursts are common, yet random and fleeting, lasting from a few milliseconds to 100 seconds.
HETE localized a gamma-ray burst named GRB021004 on Oct. 4, 2002 and notified observers worldwide within seconds. Fox pinpointed the afterglow, caused by shock waves from the explosion, from a telescope on Mt. Palomar, near San Diego. Then scientists and more than 50 telescopes in California, across the Pacific, Australia, Asia and Europe zoomed in on the spot in time to witness a new phenomenon: the ongoing energizing of the burst afterglow for more than half an hour after the event.
"Gamma-ray bursts must be many times more times powerful than we previously thought," said George Ricker, senior research scientist in MIT's Center for Space Research and principal investigator for HETE. "The gamma-ray portion of the burst is perhaps just the tip of the iceberg."
The HETE spacecraft, on an extended mission until 2004, was built by MIT under the NASA Explorer Program. The HETE program is a collaboration among MIT; NASA; Los Alamos National Laboratory, New Mexico; France's Centre National d'Etudes Spatiales (CNES), Centre d'Etude Spatiale des Rayonnements (CESR), and Ecole Nationale Superieure del'Aeronautique et de l'Espace (Sup'Aero); and Japan's Institute of Physical and Chemical Research (RIKEN). The science team includes members from the University of California (Berkeley and Santa Cruz) and the University of Chicago, as well as from Brazil, India and Italy.
At MIT, the HETE team includes Ricker, Geoffrey Crew, John Doty, Roland Vanderspek, Joel Villasenor, Nat Butler, Allyn Dullighan, Glen Monnelly, Gregory Prigozhin, Steve Kissel, Alan Levine, Francois Martel, Fred Miller; at Los Alamos National Laboratory, team members are Edward E. Fenimore, Mark Galassi, and Tanya Tavenner; at the University of California at Berkeley, team members are Kevin Hurley and J. Garrett Jernigan; at the University of California at Santa Cruz, Stanford E. Woosley; at the University of Chicago, team members are Don Lamb, Carlo Graziani, and Tim Donaghy; and NASA project scientist at Goddard Space Flight Center in Greenbelt, Md., is Thomas L. Cline.
