Swift detection of a gamma-ray burst

For the first time, a telescope has directly detected X rays from a gamma-ray burst, the most powerful type of explosion in the universe. Gamma-ray bursts, which may be generated by the sudden collapse of extremely massive stars, also are the likely birth cries of black holes.

CAUGHT IN THE ACT. Artist’s depiction of the Swift spacecraft with a gamma-ray burst in the background. NASA

The Swift spacecraft, launched by NASA late last November to study gamma-ray bursts and their afterglows, recorded the X rays on Jan. 17, during a relatively long-lived burst dubbed GRB050117. Three minutes and 12 seconds after Swift’s gamma-ray telescope found the burst, the craft automatically turned its X-ray telescope to the same point in the sky.

Previous X-ray images had captured a burst’s afterglow, but not the burst itself, notes Swift principal investigator Neil Gehrels of NASA’s Goddard Space Flight Center in Greenbelt, Md. The new images are the first to track the transition of a gamma-ray burst from its brilliant, initial flash to its slowly fading afterglow, which can last for weeks. Swift’s third instrument, a combination ultraviolet- and visible-light detector, has just completed final testing and wasn’t yet recording data when the burst erupted.

Other telescopes, both in space and on the ground, are now studying the burst’s afterglow and the region surrounding the burst.

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