News tagged with gamma ray burst
Neutrinos put cosmic ray theory on ice
(Phys.org) -- A telescope buried beneath the South Pole has failed to find any neutrinos accompanying exploding fireballs in space, undermining a leading theory of how cosmic rays are born.
Apr 20, 2012 |
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Where do the highest-energy cosmic rays come from? Not from gamma-ray bursts, says IceCube study
The IceCube neutrino telescope encompasses a cubic kilometer of clear Antarctic ice under the South Pole, a volume seeded with an array of 5,160 sensitive digital optical modules (DOMs) that precisely track ...
Apr 18, 2012 |
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Gamma-ray bursts' highest power side unveiled by Fermi telescope
(PhysOrg.com) -- Detectable for only a few seconds but possessing enormous energy, gamma-ray bursts are difficult to capture because their energy does not penetrate the Earth's atmosphere. Now, thanks to an orbiting telescope, ...
Feb 19, 2012 |
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Astrophysics and extinctions: News about planet-threatening events
Space is a violent place. If a star explodes or black holes collide anywhere in our part of the Milky Way, they'd give off colossal blasts of lethal gamma-rays, X-rays and cosmic rays and it's perfectly reasonable to expect ...
Space & Earth / Space Exploration
Oct 07, 2011 |
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Fermi's latest gamma-ray census highlights cosmic mysteries
(PhysOrg.com) -- Every three hours, NASA's Fermi Gamma-ray Space Telescope scans the entire sky and deepens its portrait of the high-energy universe. Every year, the satellite's scientists reanalyze all of ...
Sep 09, 2011 |
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Unusual gamma-ray flash may have come from star being eaten by massive black hole
A bright flash of gamma rays observed March 28 by the Swift satellite may have been the death rattle of a star falling into a massive black hole and being ripped apart, according to a team of astronomers led ...
Jun 16, 2011 |
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Bright sparks among 'Asia's Nobel Prize' winners
Two scientists who are probing the brightest flashes in the universe were Tuesday named among the winners of the Shaw Prize, the $1 million award known as the Nobel Prize of the east.
Jun 07, 2011 |
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New candidate for most distant object in universe
(PhysOrg.com) -- A gamma-ray burst detected by NASA's Swift satellite in April 2009 has been newly unveiled as a candidate for the most distant object in the universe. At an estimated distance of 13.14 billion ...
May 25, 2011 |
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Small bangs and white holes
Most gamma-ray bursts come in two flavors. Firstly, there are long duration bursts which form in dense star-forming regions and are associated with supernovae – which would understandably generate a sustained ...
May 23, 2011 |
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IceCube researchers come up empty on first neutrino test
(PhysOrg.com) -- Physicist Nathan Whitehorn and a team of researchers with the IceCube collaboration have failed to come up with evidence to prove that neutrinos come from, or are caused by, gamma ray bursts, ...
Apr 15, 2011 |
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The engine that powers short gamma-ray bursts
(PhysOrg.com) -- These explosions have been puzzling scientists for years: those brief flashes of gamma light can in fact release more energy in a fraction of a second than what our entire galaxy releases ...
Apr 08, 2011 |
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Breakthrough study confirms cause of short gamma-ray bursts
A new supercomputer simulation shows the collision of two neutron stars can naturally produce the magnetic structures thought to power the high-speed particle jets associated with short gamma-ray bursts (GRBs). ...
Apr 07, 2011 |
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Swift, Hubble, Chandra telescopes join forces to observe unprecedented explosion
(PhysOrg.com) -- NASA's Swift, Hubble Space Telescope and Chandra X-ray Observatory have teamed up to study one of the most puzzling cosmic blasts yet observed. More than a week later, high-energy radiation ...
Apr 07, 2011 |
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Rare observation of cosmic explosion
Gamma ray bursts, which are the most powerful bursts of radiation in the universe, have now been observed in direct connection with an exploding giant star - a supernova. Researchers from the Niels Bohr Institute ...
Mar 10, 2011 |
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Light dawns on dark gamma-ray bursts (w/ Video)
(PhysOrg.com) -- Gamma-ray bursts are among the most energetic events in the Universe, but some appear curiously faint in visible light. The biggest study to date of these so-called dark gamma-ray bursts, ...
Dec 16, 2010 |
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Gamma-ray burst
Gamma-ray bursts (GRBs) are flashes of gamma rays associated with extremely energetic explosions in distant galaxies. They are the most luminous electromagnetic events occurring in the universe. Bursts can last from milliseconds to nearly an hour, although a typical burst lasts a few seconds. The initial burst is usually followed by a longer-lived "afterglow" emitting at longer wavelengths (X-ray, ultraviolet, optical, infrared, and radio).
Most observed GRBs are believed to be a narrow beam of intense radiation released during a supernova event, as a rapidly rotating, high-mass star collapses to form a black hole. A subclass of GRBs (the "short" bursts) appear to originate from a different process, possibly the merger of binary neutron stars.
The sources of most GRBs are billions of light years away from Earth, implying that the explosions are both extremely energetic (a typical burst releases as much energy in a few seconds as the Sun will in its entire 10 billion year lifetime) and extremely rare (a few per galaxy per million years). All observed GRBs have originated from outside the Milky Way galaxy, although a related class of phenomena, soft gamma repeater flares, are associated with magnetars within the Milky Way. It has been hypothesized that a gamma-ray burst in the Milky Way could cause a mass extinction on Earth.
GRBs were first detected in 1967 by the Vela satellites, a series of satellites designed to detect covert nuclear weapons tests. Hundreds of theoretical models were proposed to explain these bursts in the years following their discovery, such as collisions between comets and neutron stars. Little information was available to verify these models until the 1997 detection of the first X-ray and optical afterglows and direct measurement of their redshifts using optical spectroscopy. These discoveries, and subsequent studies of the galaxies and supernovae associated with the bursts, clarified the distance and luminosity of GRBs, definitively placing them in distant galaxies and connecting long GRBs with the deaths of massive stars.
For more information about Gamma-ray burst, read the full article at
Wikipedia.
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