WASHINGTON, Jan. 21 /PRNewswire/ -- The NASA-led Swift mission has detected and
imaged its first gamma-ray burst, likely the birth cry of a brand new black hole.
The bright and long burst occurred on January 17. It was in the midst of exploding, as Swift
autonomously turned to focus in less than 200 seconds. The satellite was fast enough to
capture an image of the event with its X-Ray Telescope (XRT), while gamma rays were still
being detected with the Burst Alert Telescope (BAT).
"This is the first time an X-ray telescope has imaged a gamma-ray burst, while it was
bursting," said Dr. Neil Gehrels, Swift's Principal Investigator at NASA's Goddard Space
Flight Center, Greenbelt, Md. "Most bursts are gone in about 10 seconds, and few last
upwards of a minute. Previous X-ray images have captured the burst afterglow, not the burst
itself."
Target Region
"This is the one that didn't get away," said Prof. John Nousek, Swift's Mission Operations
Director at Penn State University, State College, Pa. "And this is what Swift was built to do:
to detect these fleeting gamma-ray bursts and focus its telescopes on them autonomously
within about a minute. The most exciting thing is this mission is just revving up."
Swift has three main instruments. The BAT detects bursts and initiates the autonomous
slewing to bring the XRT and the Ultraviolet/Optical Telescope (UVOT) within focus of the
burst. In December the BAT started detecting bursts, including a remarkable triple detection
on December 19. Today's announcement marks the first BAT detection autonomously
followed by XRT detection, demonstrating the satellite is swiftly slewing as planned. The
UVOT is still being tested, and it was not collecting data when the burst was detected.
Scientists will need several weeks to fully understand this burst, GRB050117, so named for the
date of detection. Telescopes in orbit and on Earth will turn to the precise burst location
provided by Swift to observe the burst afterglow and the region surrounding the burst.
"We are frantically analyzing the XRT data to understand the X-ray emission seen during the
initial explosion and the very early afterglow," said Dr. David Burrows, the XRT lead at Penn
State. "This is a whole new ballgame. No one has ever imaged X-rays during the transition of
a gamma-ray burst from the brilliant flash to the fading embers."
When the UVOT is fully operational, both the XRT and UVOT will provide an in-depth
observation of the gamma-ray burst and its afterglow. The burst is gone in a flash, but
scientists can study the afterglow to learn about what caused the burst, much like a detective
hunts for clues at a crime scene.
The origin of gamma-ray bursts remains a mystery. At least some appear to originate in
massive star explosions. Others might be the result of merging black holes or neutron stars.
Any of these scenarios likely will result in the formation of a new black hole.
Several of these bursts occur daily somewhere in the visible universe. No prompt X-ray
emission (coincident with the gamma-ray burst) has been previously imaged, because it
usually takes hours to turn an X-ray telescope towards a burst. Scientists expect Swift to be
fully operational by February 1.
Swift, still in its checkout phase, is an international collaboration launched on November 20,
2004. It is a NASA mission in partnership with the Italian Space Agency and the Particle
Physics and Astronomy Research Council, United Kingdom.
The spacecraft was built in collaboration with national laboratories, universities and
international partners, including Penn State University; Los Alamos National Laboratory,
New Mexico; Sonoma State University, Rohnert Park, Calif.; Mullard Space Science
Laboratory in Dorking, Surrey, England; the University of Leicester, England; Brera
Observatory in Milan; and ASI Science Data Center in Frascati, Italy.
For more information about Swift on the Web, visit:
Nasa Swift Site
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