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Gamma-ray bursts are the most luminous explosions in the cosmos. Astronomers think most occur 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 at nearly the speed of light. Artist's rendering.Credit: NASA's Goddard Space Flight Center Theorists believe that GRB jets produce gamma rays by two processes involving shock waves. Shells of material within the jet move at different speeds and collide, generating internal shock waves that result in low-energy (million electron volt, or MeV) gamma rays. As the leading edge of the jet interacts with its environment, it generates an external shock wave that results in the production of high-energy (billion electron volt, or GeV) gamma rays. Artist's rendering.Credit: NASA's Goddard Space Flight Center This illustration shows the ingredients of the most common type of gamma-ray burst. The core of a massive star (left) has collapsed, forming a black hole that sends a jet moving through the collapsing star and out into space at near the speed of light. Radiation across the spectrum arises from hot ionized gas (plasma) in the vicinity of the newborn black hole, collisions among shells of fast-moving gas within the jet (internal shock waves), and from the leading edge of the jet as it sweeps up and interacts with its surroundings (external shock).Credit: NASA's Goddard Space Flight Center RAPTOR-T is one of several robotic observatories making up the the Rapid Telescopes for Optical Response (RAPTOR) project operated by Los Alamos National Laboratory. The instrument consists of four co-aligned 0.4-meter telescopes, each with a different color filter (the "T" stands for technicolor). RAPTOR-T is designed to detect color changes in the optical flash accompanying a gamma-ray burst, which can yield information on the explosion's dynamics, environment and distance.Credit: T. Vestrand, LANL This movie shows GRB 130427A as viewed by the RAPTOR telescopes located near Los Alamos, N.M, and on Mount Haleakala on the island of Maui, Hawaii. The movie opens with wide-field images acquired by a RAPTOR All-Sky Monitor, one of the three identical systems to first detect the burst's optical flash. The movie then switches to observations from RAPTOR-T, which autonomously turned toward the burst after receiving an alert from NASA's Swift. The telescope imaged the burst for 2 hours and captured simultaneous images in four different colors.Credit: T. Vestrand, LANL Better known as NuSTAR, the Nuclear Spectroscopic Telescope Array is the first orbiting observatory able to focus high-energy X-rays. The instrument consists of two co-aligned grazing incidence telescopes with advanced optics and detectors that extend its sensitivity to higher energies (3,000 to 79,000 electron volts) than previous X-ray missions.Credit: NASA/JPL-Caltech Instruments aboard three NASA missions and the ground-based RAPTOR telescope provide the most detailed multi-energy look at changing emissions of GRB 130427A. The early pulse of gamma rays detected by Fermi's GBM exhibits behaviors confounding all models that explain the emission based on colliding shells. Visible light measured by RAPTOR closely tracks the high-energy gamma rays detected by Fermi LAT, an unexpected relationship. Data from Swift's BAT, XRT and UVOT instruments, in concert with measurements from ground telescopes, capture the evolution of the GRB over weeks and show that it shares properties with much more distant bursts. Observations by NuSTAR and Fermi LAT challenge a 12-year-old prediction of how the emission components in a GRB spectrum should change with time. The ground-based measurements shown here come from the Faulkes Telescope North, located at Haleakala Observatory in Hawaii, the Liverpool Telescope on the island of La Palma, Spain, and the MITSuME Telescopes in Japan. For clarity, this chart omits error bars for all measurements.Credit: NASA's Goddard Space Flight Center This movie shows the jet associated with a gamma-ray burst as it emerges from a collapsing star and drives into space at nearly the speed of light. The frames are part of a high-resolution 3-D hydrodynamical simulation by Davide Lazzati at North Carolina State University and Brian Morsony at the University of Wisconsin, Madison, using the Pleiades supercomputer at NASA's Ames Research Center. The movie covers the first 8 seconds following the jet's emergence from the star.Credit: Davide Lazzati (NCSU) and Brian Morsony (Univ. of Wisconsin) NASA Swift's UVOT instrument captured the fading light of GRB 130427A using images acquired through its w1 and w2 filters, which correspond to energies of 4.7 and 6.1 electron volts, respectively. The movie begins about 6 minutes after the burst triggered Fermi's GBM instrument and lasts 10.3 days. Angular width of the movie is 100 arcseconds.Credit: NASA/Swift/S. Oates, UCL-MSSL This image illustrates the ingredients of the most common type of gamma-ray burst. The core of a massive star (left) has collapsed, forming a black hole that sends a jet moving through the collapsing star and out into space at near the speed of light. Radiation across the spectrum arises from hot ionized gas (plasma) in the vicinity of the newborn black hole, collisions among shells of fast-moving gas within the jet (internal shock waves), and from the leading edge of the jet as it sweeps up and interacts with its surroundings (external shock).UnlabeledCredit: NASA's Goddard Space Flight Center NASA's Fermi Gamma-ray Space Telescope. Click here and here for spacecraft animations. NASA's Swift satellite. Click here for spacecraft animations On Thursday, Nov. 21, 2013, NASA held a media teleconference to discuss new findings related to a brilliant gamma-ray burst detected on April 27. Audio of the teleconference is available for download here.Related feature story: www.nasa.gov/content/goddard/nasa-sees-watershed-cosmic-blast-in-unique-detail/.Audio of Sylvia Zhu interview for a Science Podcast. Briefing Speakers Introduction: Paul Hertz, NASA Astrophysics Division Director, NASA Headquarters, Washington, D.C.Charles Dermer, astrophysicist, Naval Research Laboratory, Washington, D.C.Thomas Vestrand, astrophysicist, Los Alamos National Laboratory, Los Alamos, N.M.Chryssa Kouveliotou, astrophysicist, NASA’s Marshall Space Flight Center, Huntsville, Ala. Presenter 1: Charles Dermer Presenter 2: Thomas Vestrand Presenter 3: Chryssa Kouveliotou Additional Media For More InformationSee [http://www.nasa.gov/topics/universe/features/shocking-burst.html](http://www.nasa.gov/topics/universe/features/shocking-burst.html) Related pages

The Fermi LAT 60-month image, constructed from front-converting gamma rays with energies greater than 1 GeV. The most prominent feature is the bright band of diffuse glow along the map's center, which marks the central plane of our Milky Way galaxy. The gamma rays are mostly produced when energetic particles accelerated in the shock waves of supernova remnants collide with gas atoms and even light between the stars. Hammer projection. Image credit: NASA/DOE/Fermi LAT Collaboration The Fermi LAT 60-month image, constructed from front-converting gamma rays with energies greater than 1 GeV. The most prominent feature is the bright band of diffuse glow along the map's center, which marks the central plane of our Milky Way galaxy. The gamma rays are mostly produced when energetic particles accelerated in the shock waves of supernova remnants collide with gas atoms and even light between the stars. Equidistant cylindrical projection. Image credit: NASA/DOE/Fermi LAT Collaboration This plot overlays the locations of three reference planes on the Fermi sky map: the celestial equator (the plane of Earth's equator projected onto the sky), the ecliptic (the annual apparent path of the sun around the sky as well as the plane of Earth's orbit), and the galactic equator, which marks the central plane of our Milky Way galaxy.Image credit: NASA/DOE/Fermi LAT Collaboration ConstellationsThis plot overlays the boundaries of traditional constellations on the Fermi sky map. The area of each constellation is labeled with its three-letter abbreviation.Image credit: NASA/DOE/Fermi LAT Collaboration PulsarsThis plot identifies selected pulsars detected by Fermi's LAT. A pulsar is a type of rapidly rotating neutron star that emits electromagnetic energy at periodic intervals. A neutron star is the closest thing to a black hole that astronomers can observe directly, crushing half a million times more mass than Earth into a sphere no larger than a city. Its matter is so compressed that even a teaspoonful weighs as much as a mountain. One pulsar shines especially bright for Fermi. Called Vela, it spins 11 times a second and is the brightest persistent source of gamma rays the LAT sees. Image credit: NASA/DOE/Fermi LAT Collaboration 2PSC PulsarsThis plot locates all 117 pulsars in the Fermi LAT Two-year Point Source Catalog.. Active GalaxiesThis plot identifies selected active galaxies detected by Fermi's LAT. An active galaxy is one whose central region exhibits strong emissions at many different wavelengths. What powers these emissions is a well-fed black hole millions of times more massive than our sun. Some of the infalling gas becomes diverted into a pair of oppositely directed particle jets streaming outward at nearly the speed of light. Famous members of this class include NGC 1275 (the bright radio source Perseus A); M87, which sports a jet that can be seen in visible light; and Centaurus A (NGC 5128), whose jet has been operating long enough to form two lobes of radio- and gamma-ray-emitting gas, each up to a million light-years long. Image credit: NASA/DOE/Fermi LAT Collaboration BlazarsThis plot highlights the most extreme type of active galaxy: blazars. They are the most common objects detected by Fermi's LAT, making up 57 percent of the total sources in the second Fermi catalog.. Like all active galaxies, blazars are powered by matter falling toward a central supermassive black hole. Some of the infalling material becomes diverted into oppositely directed particle jets that travel outward near the speed of light. What distinguishes blazars is that the galaxy happens to be oriented so that we're looking directly into the jet, which accounts for their intensity and rapid changes in brightness. Some blazars were originally detected in visible light and mistaken for variable stars. The term blazar was coined in 1978 by combining the name of one of these objects (BL Lacertae) with quasar, a word for another class of active galaxy that exhibits less extreme behavior. Image credit: NASA/DOE/Fermi LAT Collaboration Normal galaxiesThis plot highlights a selection of bright normal galaxies detected by Fermi's LAT. M31 (the Andromeda galaxy) and the Large and Small Magellanic Clouds, two of the Milky Way's many small satellites, qualify as normal galaxies. Astronomers classify M82 and NGC 253 as "starburst" galaxies because they host an unusually high rate of star formation, as well as explosive stellar deaths (supernovae).Image credit: NASA/DOE/Fermi LAT Collaboration Supernova remnantsThis plot shows selected supernova remnants detected by Fermi's LAT. A supernova remnant is the expanding shell of debris caused by the explosion of a star, which creates a nebula that radiates gamma rays, radio waves, X-rays, and light for thousands of years. Cassiopeia A and Tycho, with ages less than 500 years, are among the galaxy's youngest and appear only as point sources in the map. Fermi's LAT can make out extended structure in remnants like W44, IC 443 (the Jellyfish Nebula) and the Cygnus Loop, which are more than 5,000 years old. Image credit: NASA/DOE/Fermi LAT Collaboration HMBs and globular clustersThis plot shows high-mass binary systems and globular star clusters detected by Fermi's LAT. Few pairings in astronomy are as peculiar as high-mass binaries, where a hot blue-white star many times the sun's mass and temperature is joined by a compact companion no bigger than Earth — and likely much smaller. Depending on the system, this companion may be a burned-out star known as a white dwarf, a city-sized remnant called a neutron star (also known as a pulsar) or, most exotically, a black hole. One of the high-mass binaries plotted here, 1FGL J1018.6-5856, was discovered by the Fermi team.Globular clusters are dense, roughly spherical groupings of tens of thousands of old stars. Astronomers have identified about 150 globular clusters in our galaxy, and the three plotted here — NGC 6266, Terzan 5, and 47 Tucanae — are bright sources for Fermi's LAT. Their brightness at these energies is likely due to the combined gamma-ray glow of many unresolved millisecond pulsars. Image credit: NASA/DOE/Fermi LAT Collaboration Fermi's portrait of the sky at energies beyond 1 GeV has steadily deepened with the accumulation of more data. This animation compares views of a 20-degree-wide region in the constellation Virgo after the LAT's first and fifth year of operations. Many additional strong sources (yellow, red) appear in the latest image. Most are black-hole-powered galaxies called blazars. In both images, the brightest source is the blazar 3C 279. The view is centered at R.A. 13h 00m, Dec. -2d 00m. Image credit: NASA/DOE/Fermi LAT Collaboration This image identifies several blazars and one pulsar (PSR J1312+00) in a 20-degree-wide patch in the constellation Virgo. The view is centered at R.A. 13h 00m, Dec. -2d 00m. The LAT image is a five-year exposure of gamma rays with energies greater than 1 billion electron volts (GeV). Brighter colors indicate brighter gamma-ray sources. Image credit: NASA/DOE/Fermi LAT Collaboration Fermi LAT one-year exposure of a 20-degree-wide region in the constellation Virgo. Brighter colors indicate brighter gamma-ray sources. Image credit: NASA/DOE/Fermi LAT Collaboration Fermi LAT five-year exposure of a 20-degree-wide region in the constellation Virgo. Brighter colors indicate brighter gamma-ray sources. Image credit: NASA/DOE/Fermi LAT Collaboration This all-sky view shows how the sky appears at energies greater than 1 billion electron volts (GeV) according to five years of data from NASA's Fermi Gamma-ray Space Telescope. (For comparison, the energy of visible light is between 2 and 3 electron volts.) The image contains 60 months of data from Fermi's Large Area Telescope; for better angular resolution, the map shows only gamma rays converted at the front of the instrument's tracker. Brighter colors indicate brighter gamma-ray sources. The map is shown in galactic coordinates, which places the midplane of our galaxy along the center. The five-year Fermi map is available in multiple resolutions below, along with additional plots containing reference information and identifying some of the brightest sources. For More InformationSee [http://www.nasa.gov/content/goddard/nasas-fermi-celebrates-five-years-in-space-enters-extended-mission/](http://www.nasa.gov/content/goddard/nasas-fermi-celebrates-five-years-in-space-enters-extended-mission/) Related pages