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.
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
"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.
Francis Reddy | EurekAlert!
Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State
What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy