Latest Gamma-ray burst Stories

2009-11-02 14:05:00

Nearby galaxies undergoing a furious pace of star formation also emit lots of gamma rays, say astronomers using NASA's Fermi Gamma-ray Space Telescope. Two so-called "starburst" galaxies, plus a satellite of our own Milky Way galaxy, represent a new category of gamma-ray-emitting objects detected both by Fermi and ground-based observatories. "Starburst galaxies have not been accessible in gamma rays before," said Fermi team member Seth Digel, a physicist at SLAC National Accelerator...

2009-10-29 07:53:16

VLA sees most distant object in universe, gets key physics data Astronomers using the National Science Foundation's Very Large Array (VLA) radio telescope have gained tantalizing insights into the nature of the most distant object ever observed in the Universe -- a gigantic stellar explosion known as a Gamma Ray Burst (GRB). The explosion was detected on April 23 by NASA's Swift satellite, and scientists soon realized that it was more than 13 billion light-years from Earth. It represents an...

2009-10-28 13:25:00

During its first year of operations, NASA's Fermi Gamma Ray Space Telescope mapped the extreme sky with unprecedented resolution and sensitivity. It captured more than 1,000 discrete sources of gamma rays -- the highest-energy form of light. Capping these achievements was a measurement that provided rare experimental evidence about the very structure of space and time, unified as space-time in Einstein's theories. "Physicists would like to replace Einstein's vision of gravity -- as expressed...

2009-09-18 09:55:00

Black holes are invading stars, providing a radical explanation to bright flashes in the universe that are one of the biggest mysteries in astronomy today. The flashes, known as gamma ray bursts, are beams of high energy radiation "“ similar to the radiation emitted by explosions of nuclear weapons "“ produced by jets of plasma from massive dying stars. The orthodox model for this cosmic jet engine involves plasma being heated by neutrinos in a disk of matter that forms around a...

2009-09-09 11:45:00

Scientists at the Naval Research Laboratory (NRL) Space Science Division and a team of international researchers have positively identified cosmic sources of gamma-ray emissions through the discovery of 16 pulsating neutron stars. Using the Large Area Telescope (LAT), the primary instrument on NASA's Fermi Gamma-ray Space Telescope satellite, the discoveries were made by conducting blind frequency searches on the sparse photon data provided by the LAT. The photons had energies between 20...

2009-08-12 12:42:02

The stellar explosions known as type 1a supernovae have long been used as "standard candles," their uniform brightness giving astronomers a way to measure cosmic distances and the expansion of the universe. But a new study published this week in Nature reveals sources of variability in type 1a supernovae that will have to be taken into account if astronomers are to use them for more precise measurements in the future.The discovery of dark energy, a mysterious force that is accelerating the...

2009-07-02 13:35:00

High-resolution radio, gamma-ray observations reveal site of relativistic particle acceleration in galaxy M 87An international collaboration of 390 scientists reports the discovery of an outburst of very-high-energy (VHE) gamma radiation from the giant radio galaxy Messier 87 (M 87), accompanied by a strong rise of the radio flux measured from the direct vicinity of its super-massive black hole.The combined results give first experimental evidence that particles are accelerated to extremely...

2009-06-08 11:25:00

Gamma-ray bursts, with their ability to pierce through gas and dust to shine brightly across the universe, are revealing areas of intense star formation and stellar death where astronomers have been unable to look - the dusty corners of otherwise dust-free galaxies.The conclusion comes from a survey of "dark" gamma-ray bursts - bright in gamma- and X-ray emissions, but with little or no visible light - reported today (Monday, June 8) at a meeting of the American Astronomical Society in...

2009-05-25 08:55:00

ESO's Very Large Telescope "” Europe's flagship facility for ground-based astronomy "” has been equipped with the first of its second generation instruments: X-shooter. It can record the entire spectrum of a celestial object in one shot "” from the ultraviolet to the near-infrared "” with high sensitivity. This unique new instrument will be particularly useful for the study of distant exploding objects called gamma-ray bursts. "X-shooter offers a capability that is...

2009-05-04 11:05:00

Since its launch last June, NASA's Fermi Gamma-ray Space Telescope has discovered a new class of pulsars, probed gamma-ray bursts and watched flaring jets in galaxies billions of light-years away. Today at the American Physical Society meeting in Denver, Colo., Fermi scientists revealed new details about high-energy particles implicated in a nearby cosmic mystery. "Fermi's Large Area Telescope is a state-of-the-art gamma-ray detector, but it's also a terrific tool for investigating the...

Latest Gamma-ray burst Reference Libraries

2004-10-19 04:45:43

Gamma-Ray Astronomy -- Gamma-ray astronomy is the astronomical study of gamma rays. Long before experiments could detect gamma rays emitted by cosmic sources, scientists had known that the universe should be producing these photons. Work by Feenberg and Primakoff in 1948, Hayakawa and Hutchinson in 1952, and, especially, Morrison in 1958 had led scientists to believe that a number of different processes which were occurring in the universe would result in gamma-ray emission. These...

2004-10-19 04:45:41

Hypernova -- A hypernova is a theoretical type of supernova produced when exceptionally large stars collapse at the end of their lifespan. In a hypernova, the core of the star collapses directly into a black hole and two extremely energetic jets of plasma are emitted from its rotational poles at nearly light speed. These jets emit intense gamma rays, and are a candidate explanation for gamma ray bursts. Theorists have come up with several plausible explanations for hypernovae. It may...

2004-10-19 04:45:41

Gamma-Ray Burst -- In astronomy, Gamma-ray bursters (GRBs) are flashes of gamma rays that last from seconds to hours, the longer ones being followed by several days of X-ray afterglow. They occur at random positions in the sky several times each day. They are now believed to result from tremendous explosions in far away galaxies, during the creation of a black hole from a dying star or two colliding neutron stars. The black hole, surrounded by a rotating disk of matter falling into it,...

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