NASA Satellite Detects Explosion from Edge of Visible Universe
International telescopes also help locate most distant explosion ever detected
Scientists using NASA's Swift satellite and international ground-based telescopes have detected the most distant
explosion yet, a gamma-ray burst from the edge of the visible universe.
Gamma-ray bursts, the most luminous physical phenomenon in the universe, are flashes of gamma rays that last from
seconds to hours. They occur at apparently random positions in the sky several times each day.
The latest powerful burst, detected September 4, marks the death of a massive star and the birth of a black hole,
according to a September 12 NASA news release. It comes from an era soon after stars and galaxies first formed, about
500 million to 1 billion years after the Big Bang.
The Big Bang theory is the main scientific theory about the origin of the universe. According to the Big Bang, the
universe was created 10-20 billion years ago from a cosmic explosion that hurled matter in all directions.
"We designed Swift to look for faint bursts coming from the edge of the universe," said Swift principal investigator
Neil Gehrels of NASA Goddard Space Flight Center in Maryland.
"Now we've got one and it's fascinating,” he added. “For the first time we can learn about individual stars from near
the beginning of time. There are surely many more out there.”
Swift's international partners include the United Kingdom and Italy.
This burst comes from a lone star. Scientists say it is puzzling how a single star could have generated enough energy to
be seen across the universe. The science team has not yet determined the nature of the exploded star.
Detecting this burst confirms that large stars mingled with the oldest quasars. Quasars are super-massive black holes
containing the mass of billions of stars.
The detection also confirms that even-more-distant star explosions can be studied through combined observations of Swift
and a network of world-class telescopes. Swift detected the burst and relayed its coordinates in minutes to scientists
around the world.
Instruments involved in the work include the Southern Observatory for Astrophysical Research telescope in Chile, funded
by the United States and Brazil; and one of the twin Gemini Observatory telescopes in Chile funded by the U.S. National
Science Foundation, the United Kingdom, Canada, Chile, Australia, Argentina and Brazil.
A team led by Nobuyuki Kawai of the Tokyo Institute of Technology used the Subaru Observatory on Mauna Kea in Hawaii to
confirm the distance.
Information about the explosion is available at NASA’s Web site.
Text of the NASA press release follows:
(begin text)
NASA Goddard Space Flight Center
September 12, 2005
[Greenbelt, Maryland]
MOST DISTANT EXPLOSION DETECTED, SMASHES PREVIOUS RECORD
Scientists using NASA's Swift satellite and several ground-based telescopes have detected the most distant explosion
yet, a gamma-ray burst from the edge of the visible universe.
This powerful burst was detected September 4. It marks the death of a massive star and the birth of a black hole. It
comes from an era soon after stars and galaxies first formed, about 500 million to 1 billion years after the Big Bang.
"We designed Swift to look for faint bursts coming from the edge of the Universe," said Swift principal investigator Dr.
Neil Gehrels of NASA Goddard Space Flight Center in Greenbelt, Md. "Now we've got one and it's fascinating. For the
first time we can learn about individual stars from near the beginning of time. There are surely many more out there,"
he added.
Only one quasar has been discovered at a greater distance. Quasars are super-massive black holes containing the mass of
billions of stars. This burst comes from a lone star. Scientists say it is puzzling how a single star could have
generated so much energy as to be seen across the entire Universe. The science team has not yet determined the nature of
the exploded star. A detailed analysis is forthcoming.
Scientists measure cosmic distances via redshift, the extent to which light is "shifted" toward the red, or lower
energy, part of the electromagnetic spectrum during the light's long journey across the Universe. The greater the
distance, the higher the redshift. The September 4 burst, named GRB 050904, has a redshift of 6.29, which translates to
a distance of about 13 billion light-years from Earth. The Universe is thought to be 13.7 billion years old. The
previous most distant gamma-ray burst had a redshift of 4.5. The most distant quasar known is at a redshift of 6.4.
This burst was also very long, lasting more than 200 seconds, whereas most bursts last only about 10 seconds. The
detection of this burst confirms that massive stars mingled with the oldest quasars. The detection also confirms that
even more distant star explosions can be studied through combined observations of Swift and the network of world-class
telescopes.
"This is uncharted territory," said Dr. Daniel Reichart, University of North Carolina (UNC), Chapel Hill, who
spearheaded the distance measurement. "This burst smashes the old distance record by 500 million light-years. We are
finally starting to see the remnants of some of the oldest objects in the Universe," he added.
Swift detected the burst and relayed its coordinates within minutes to scientists around the world. Reichart's team
discovered the afterglow using the Southern Observatory for Astrophysical Research (SOAR) telescope atop Cerro Pachon,
Chile. Over the next several nights, the UNC team used SOAR and the Gemini South telescope, also on Cerro Pachon, to
calculate a redshift of greater than 6 using a light filtering technique. A team led by Nobuyuki Kawai of the Tokyo
Institute of Technology used the Subaru Observatory on Mauna Kea, Hawaii, to confirm the distance and fine-tune the
redshift measurement to 6.29, using a technique called spectroscopy.
"The earliest stars exploded eons ago, we know very little about them," said Josh Haislip, a UNC team member who
analyzed data from SOAR. "One of the best ways we can study them is by watching for their explosions. Swift can pinpoint
the location of the explosions, and telescopes such as SOAR can study the composition of the debris to understand where
and when these stars formed and what they were made of," he added.
The SOAR telescope is funded by the U.S. National Optical Astronomy Observatory, Tucson, Ariz., through the National
Science Foundation (NSF), Arlington, Va.; the Ministry of Science of Brazil; Michigan State University, East Lansing;
and UNC. The twin Gemini Observatory telescopes represent an international partnership funded in part by the NSF.
Goddard manages the Swift mission for NASA's Science Mission Directorate, Washington. Mission operations are conducted
by Penn State University, University Park. Swift's other national laboratories, universities and international partners
include the Los Alamos National Laboratory, N.M.; Sonoma State University, Rohnert Park, Calif.; the United Kingdom; and
Italy.