By the end of this day, somewhere in the visible
universe a new black hole will have formed. Gamma-ray bursts
(GRBs), the most distant and powerful explosions known, are
likely the birth cries of these new black holes.
NASA’s Swift mission is dedicated to studying the gamma-ray
burst/black hole connection. The Swift spacecraft, an
international collaboration, is scheduled to lift off in
November aboard a Delta II rocket from Cape Canaveral Air
Force Station, Fla.
“Swift caps off a 30-year hunt to understand the nature of
gamma-ray bursts, flashes of light that burn as brightly as a
billion billion suns,” said Dr. Anne Kinney, Director of the
Universe Division, NASA Headquarters, Washington. “Swift is
fine-tuned to quickly locate these bursts and study them in
several different wavelengths before they disappear forever.
Swift is a little satellite with a big appetite,” she said.
Gamma-ray bursts are fleeting events, lasting only a few
milliseconds to a few minutes, never to appear in the same
spot again. They occur from our vantage point about once a
day. Some bursts appear to be from massive star explosions
that form black holes.
The Swift observatory comprises three telescopes, which work
in tandem to provide rapid identification and multi-
wavelength follow-up of GRBs and their afterglows. Within 20
to 75 seconds of a detected GRB, the observatory will rotate
autonomously, so the onboard X-ray and optical telescopes can
view the burst. The afterglows will be monitored over their
durations, and the data will be rapidly released to the
public.
The afterglow phenomenon follows the initial gamma-ray flash
in most bursts. It can linger in X-ray light, optical light
and radio waves for hours to weeks, providing great detail.
The crucial link here, however, is having a precise location
to direct other telescopes. Swift is the first satellite to
provide this capability with both great precision and speed.
“We expect to detect and analyze over 100 gamma-ray bursts a
year,” said Dr. Neil Gehrels, Swift’s Principal Investigator
at NASA’s Goddard Space Flight Center (GSFC) in Greenbelt,
Md. “Swift will lead to a windfall of discovery on these most
powerful explosions in the universe.”
While the link between some bursts and massive star
explosions appears firm, other bursts may signal the merger
of neutron stars or black holes orbiting each other in exotic
binary star systems. Swift will determine whether there are
different classes of gamma-ray bursts associated with a
particular origin scenario. Swift will be fast enough to
identify afterglows from short bursts, if they exist.
Afterglows have only been seen for bursts lasting longer than
two seconds.
“Some bursts likely originate from the farthest reaches, and
hence earliest epoch, of the universe,” said Swift Mission
Director John Nousek. He is a professor of astronomy and
astrophysics at Penn State’s University Park, Pa., campus.
“They act like beacons shining through everything along their
paths, including the gas between and within galaxies along
the line of sight,” he said.
Swift notifies the community, which includes museums, general
public, and scientists at world-class observatories, via the
GSFC-maintained Gamma-ray Burst Coordinates Network (GCN). A
network of dedicated ground-based robotic telescopes
distributed around the world awaits Swift-GCN alerts. The
Swift Mission Operations Center, located at Penn State’s
University Park campus, controls the Swift observatory and
provides continuous burst information.
Swift, a medium-class explorer mission, is managed by GSFC.
Swift is a NASA mission with participation of the Italian
Space Agency and the Particle Physics and Astronomy Research
Council in the United Kingdom. It was built in collaboration
with national laboratories, universities and international
partners, including Penn State University; Los Alamos
National Laboratory in New Mexico; Sonoma State University,
Rohnert Park, Calif.; Mullard Space Science Laboratory in
Dorking, Surrey, England; the University of Leicester,
England and the Brera Observatory in Milan, Italy.
More information about Swift is available on the Internet at:
