On April 27, a blast of light from a dying star in a distant galaxy became
the focus of astronomers around the world. The explosion, known as a gamma-ray
burst and designated GRB 130427A, tops the charts as one of the brightest ever
seen.
A trio of NASA satellites, working in concert with ground-based robotic
telescopes, captured never-before-seen details that challenge current
theoretical understandings of how gamma-ray bursts work.
Youtube Override:
This animation shows the most common type of
gamma-ray burst, thought to occur when a massive star collapses, forms a black
hole, and blasts particle jets outward at nearly the speed of light. Viewing
into a jet greatly boosts its apparent brightness. A Fermi image of GRB 130427A
ends the sequence.
Image Credit:
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"We expect to see an event like this only once or twice a century, so we're
fortunate it happened when we had the appropriate collection of sensitive space
telescopes with complementary capabilities available to see it," said Paul
Hertz, director of NASA's Astrophysics Division in Washington.
Gamma-ray bursts are the most luminous explosions in the cosmos, thought to
be triggered when the core of a massive star runs out of nuclear fuel, collapses
under its own weight, and forms a black hole. The black hole then drives jets of
particles that drill all the way through the collapsing star and erupt into
space at nearly the speed of light.
Gamma-rays are the most energetic form of light. Hot matter surrounding a new
black hole and internal shock waves produced by collisions within the jet are
thought to emit gamma-rays with energies in the million-electron-volt (MeV)
range, or roughly 500,000 times the energy of visible light. The most energetic
emission, with billion-electron-volt (GeV) gamma rays, is thought to arise when
the jet slams into its surroundings, forming an external shock wave.
The Gamma-ray Burst Monitor (GBM) aboard NASA's Fermi Gamma-ray Space
Telescope captured the initial wave of gamma rays from GRB 130427A shortly after
3:47 a.m. EDT April 27. In its first three seconds alone, the "monster burst"
proved brighter than almost any burst previously observed.
In the most common type of gamma-ray burst,
illustrated here, a dying massive star forms a black hole (left), which drives a
particle jet into space. Light across the spectrum arises from hot gas near the
black hole, collisions within the jet, and from the jet's interaction with its
surroundings.
Image Credit: NASA's Goddard Space Flight
Center
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"The spectacular results from Fermi GBM show that our widely accepted picture
of MeV gamma rays from internal shock waves is woefully inadequate," said Rob
Preece, a Fermi team member at the University of Alabama in Huntsville who led
the GBM study.
NASA's Swift Gamma-ray Burst Mission detected the burst almost simultaneously
with the GBM and quickly relayed its position to ground-based observatories.
Telescopes operated by Los Alamos National Laboratory in New Mexico as part
of the Rapid Telescopes for Optical Response (RAPTOR) Project quickly turned to
the spot. They detected an optical flash that peaked at magnitude 7 on the
astronomical brightness scale, easily visible through binoculars. It is the
second-brightest flash ever seen from a gamma-ray burst.
Just as the optical flash peaked, Fermi's Large Area Telescope (LAT) detected
a spike in GeV gamma-rays reaching 95 GeV, the most energetic light ever seen
from a burst. This relationship between a burst's optical light and its
high-energy gamma-rays defied expectations.
"We thought the visible light for these flashes came from internal shocks,
but this burst shows that it must come from the external shock, which produces
the most energetic gamma-rays," said Sylvia Zhu, a Fermi team member at the
University of Maryland in College Park.
The LAT detected GRB 130427A for about 20 hours, far longer than any previous
burst. For a gamma-ray burst, it was relatively nearby. Its light traveled 3.8
billion years before arriving at Earth, about one-third the travel time for
light from typical bursts.
"Detailed observations by Swift and ground-based telescopes clearly show that
GRB 130427A has properties more similar to typical distant bursts than to nearby
ones," said Gianpiero Tagliaferri, a Swift team member at Brera Observatory in
Merate, Italy.
These maps show the sky at energies above 100 MeV
as seen by Fermi's LAT instrument. Left: The sky during a 3-hour interval before
GRB 130427A. Right: A 3-hour map ending 30 minutes after the burst. GRB 130427A
was located in the constellation Leo, near its border with Ursa
Major.
Image Credit: NASA/DOE/Fermi LAT Collaboration
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This extraordinary event enabled NASA's newest X-ray observatory, the Nuclear
Spectroscopic Telescope Array (NuSTAR), to make a first-time detection of a
burst afterglow in high-energy, or "hard," X-rays after more than a day. Taken
together with Fermi LAT data, these observations challenge long-standing
predictions.
Swift's X-Ray Telescope took this 0.1-second
exposure of GRB 130427A at 3:50 a.m. EDT on April 27, just moments after Fermi
and Swift detected the outburst. The image is 6.5 arcminutes
across.
Image Credit: NASA/Swift/Stefan Immler
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RB 130427A is the subject of five papers published online Nov. 21. Four of
these, published by Science Express, highlight contributions by Fermi, Swift and
RAPTOR. The NuSTAR study is published in The Astrophysical Journal Letters.
NASA's Fermi Gamma-ray Space Telescope is an international and multi-agency
astrophysics and particle physics partnership managed by NASA's Goddard Space
Flight Center in Greenbelt, Md., and supported by the U.S. Department of
Energy's Office of Science. Goddard also manages NASA's Swift mission, which is
operated in collaboration with Pennsylvania State University in University Park,
Pa., and international partners. NASA's NuSTAR mission is led by the California
Institute of Technology and managed by NASA's Jet Propulsion Laboratory, both in
Pasadena, with contributions from international partners.
Related Links
›
Download additional graphics from NASA Goddard's Scientific Visualization Studio
› Papers on Science Express
› NuSTAR paper
› "NASA's Fermi, Swift See 'Shockingly Bright' Burst" (05.03.13)
› "NASA's Fermi Telescope Sees Most Extreme Gamma-ray Blast Yet" (02.19.09)
› "'Naked-Eye' Gamma-Ray Burst Was Aimed Squarely At Earth" (09.10.08)
› NASA's Fermi Gamma-ray Space Telescope
› NASA's Swift mission
› NASA's NuSTAR mission
› Papers on Science Express
› NuSTAR paper
› "NASA's Fermi, Swift See 'Shockingly Bright' Burst" (05.03.13)
› "NASA's Fermi Telescope Sees Most Extreme Gamma-ray Blast Yet" (02.19.09)
› "'Naked-Eye' Gamma-Ray Burst Was Aimed Squarely At Earth" (09.10.08)
› NASA's Fermi Gamma-ray Space Telescope
› NASA's Swift mission
› NASA's NuSTAR mission
Francis Reddy
NASA's Goddard Space Flight Center, Greenbelt, Md.
NASA's Goddard Space Flight Center, Greenbelt, Md.
NASA Missions Study 'Watershed' Cosmic Explosion in
Unparalleled Detail
On April 27, a blast of light from a dying star in a distant galaxy became
the focus of astronomers around the world. The explosion, known as a gamma-ray
burst and designated GRB 130427A, tops the charts as one of the brightest ever
seen.
A trio of NASA satellites, working in concert with ground-based robotic
telescopes, captured never-before-seen details that challenge current
theoretical understandings of how gamma-ray bursts work.
"We expect to see an event like this only once or twice a century, so we're
fortunate it happened when we had the appropriate collection of sensitive space
telescopes with complementary capabilities available to see it," said Paul
Hertz, director of NASA's Astrophysics Division in Washington.
Gamma-ray bursts are the most luminous explosions in the cosmos, thought to
be triggered when the core of a massive star runs out of nuclear fuel, collapses
under its own weight, and forms a black hole. The black hole then drives jets of
particles that drill all the way through the collapsing star and erupt into
space at nearly the speed of light.
Gamma-rays are the most energetic form of light. Hot matter surrounding a new
black hole and internal shock waves produced by collisions within the jet are
thought to emit gamma-rays with energies in the million-electron-volt (MeV)
range, or roughly 500,000 times the energy of visible light. The most energetic
emission, with billion-electron-volt (GeV) gamma rays, is thought to arise when
the jet slams into its surroundings, forming an external shock wave.
The Gamma-ray Burst Monitor (GBM) aboard NASA's Fermi Gamma-ray Space
Telescope captured the initial wave of gamma rays from GRB 130427A shortly after
3:47 a.m. EDT April 27. In its first three seconds alone, the "monster burst"
proved brighter than almost any burst previously observed.
"The spectacular results from Fermi GBM show that our widely accepted picture
of MeV gamma rays from internal shock waves is woefully inadequate," said Rob
Preece, a Fermi team member at the University of Alabama in Huntsville who led
the GBM study.
NASA's Swift Gamma-ray Burst Mission detected the burst almost simultaneously
with the GBM and quickly relayed its position to ground-based observatories.
Telescopes operated by Los Alamos National Laboratory in New Mexico as part
of the Rapid Telescopes for Optical Response (RAPTOR) Project quickly turned to
the spot. They detected an optical flash that peaked at magnitude 7 on the
astronomical brightness scale, easily visible through binoculars. It is the
second-brightest flash ever seen from a gamma-ray burst.
Just as the optical flash peaked, Fermi's Large Area Telescope (LAT) detected
a spike in GeV gamma-rays reaching 95 GeV, the most energetic light ever seen
from a burst. This relationship between a burst's optical light and its
high-energy gamma-rays defied expectations.
"We thought the visible light for these flashes came from internal shocks,
but this burst shows that it must come from the external shock, which produces
the most energetic gamma-rays," said Sylvia Zhu, a Fermi team member at the
University of Maryland in College Park.
The LAT detected GRB 130427A for about 20 hours, far longer than any previous
burst. For a gamma-ray burst, it was relatively nearby. Its light traveled 3.8
billion years before arriving at Earth, about one-third the travel time for
light from typical bursts.
"Detailed observations by Swift and ground-based telescopes clearly show that
GRB 130427A has properties more similar to typical distant bursts than to nearby
ones," said Gianpiero Tagliaferri, a Swift team member at Brera Observatory in
Merate, Italy.
This extraordinary event enabled NASA's newest X-ray observatory, the Nuclear
Spectroscopic Telescope Array (NuSTAR), to make a first-time detection of a
burst afterglow in high-energy, or "hard," X-rays after more than a day. Taken
together with Fermi LAT data, these observations challenge long-standing
predictions.
GRB 130427A is the subject of five papers published online Nov. 21. Four of
these, published by Science Express, highlight contributions by Fermi, Swift and
RAPTOR. The NuSTAR study is published in The Astrophysical Journal Letters.
NASA's Fermi Gamma-ray Space Telescope is an international and multi-agency
astrophysics and particle physics partnership managed by NASA's Goddard Space
Flight Center in Greenbelt, Md., and supported by the U.S. Department of
Energy's Office of Science. Goddard also manages NASA's Swift mission, which is
operated in collaboration with Pennsylvania State University in University Park,
Pa., and international partners. NASA's NuSTAR mission is led by the California
Institute of Technology and managed by NASA's Jet Propulsion Laboratory, both in
Pasadena, with contributions from international partners.
For images and video related to this release, visit:
For more information about Fermi, visit:
For more information on Swift, visit:
For more information about NuSTAR, visit:
NASA
Guillermo Gonzalo Sánchez Achutegui
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