fr en es pt
astronomy
 
 
 
 
        rss astronoo

Gamma-ray burst

Mystery of gamma ray bursts

 Automatic translationAutomatic translation Category: universe
Updated June 01, 2013

In the Universe, the cosmic events of a power considerable release incalculable energy.
These cosmic events are not uncommon, however. Imagine that the whole mass of the Sun, within a few seconds, is converted into pure energy (E = MC2).
So the high-energy radiation, cross the entire galaxy.
This is the kind of cosmic events that U.S. scientists have discovered by accident in 1967 while trying to detect any traces of nuclear explosions, from the Russian.
The U.S. military satellites of the "Project Vela" the first orbit in 1963, were responsible for monitoring the implementation of the Treaty on the prohibition of atmospheric nuclear tests. It was here that the first gamma-ray bursts were observed.
These cosmic phenomena are of short duration, a few seconds, and difficult to observe because they leave little time to orient precisely the ground and space telescopes, the most sensitive.
These are as mysterious cosmic hot flashes that occur anywhere in the distant sky, with no real source said. They are distributed randomly on the celestial sphere. When the astronomers were able to observe the location of the source, all visible traces had disappeared.
Gamma-ray bursts were so elusive that few astronomers guiding their research on this puzzle. Some thought that these bursts came from neutron stars, located in our galaxy.
We see our galaxy by the slice, these flashes should be received by the slice, as they were distributed in all directions of the cosmos.

 

These flashes could only come from other galaxies, what power it had these puffs to reach us?
Unimaginable power, billions of billions times that of the Sun and that is what was a problem for scientists because these flashes were more distant, they should be more powerful.
Explosions also had to have huge side effects, like, leave a trace, a light volatile.
Scientists detect this light was essential for understanding the late gamma-ray bursts from the bottom of the cosmos. But to capture that light had to be delayed pointing telescopes, very quickly to the gamma source assumed.
February 28, 1997, with Italian-Dutch satellite BeppoSAX, equipped with a gamma radiation detector, which scientists observe, for the first time, an afterglow in other wavelengths of radiation that gamma.
Since 2004, the SWIFT telescope, allows rapid scoring of the two instruments and optical imaging X.
With SWIFT, scientists can observe the afterglow of the burst in the first minutes after the gamma flash.
SWIFT, the NASA satellite designed specifically to explain these phenomena. But another mystery was solved.
What is the celestial body that can generate a titanic force in the origin of gamma ray bursts?
It seems that GRBs are related to final stages of stellar evolution and black holes.
These are extremely powerful cosmic phenomena, probably the most powerful of the universe after the Big Bang itself.

 gamma ray bursts

Image: Gamma ray bursts, these bursts are mysterious cosmic flashes that appear as anywhere in the distant sky, with no real source said. They are distributed randomly on the celestial sphere. It seems that GRBs are related to final step of hypernovae and black holes. But even the lack of a black hole to generate these powerful bursts of gamma rays is observed. To emit as much energy must be more that the black hole rotates very fast on himself. This large electric motor with a power absolutely insane then produces jets of energy intense bursts of gamma rays visible from Earth. Image of the documentary 'the end of a star'

SWIFT Gamma-Ray Explorer

    

SWIFT is a space telescope, launched on a low Earth orbit, November 20, 2004 at 5:16:00 p.m. UTC, by a Delta 2 rocket.
The purpose of SWIFT is to study gamma-ray bursts. Gamma-ray bursts, these brief but intense explosion, occurring about once a day in the universe. These are real hot burning of gamma radiation coming from all directions of the sky and last from a few milliseconds to a few hundred seconds. Scientists wonder if these are births of black holes, stellar explosions, collisions of neutron stars, dislocations of stars by a supermassive black hole, or is it another exotic phenomenon that causes these explosions?
Since 2004, scientists have with SWIFT, a dedicated tool to answer these questions and solve the mystery of gamma ray bursts. A few seconds after detection of a gamma burst, SWIFT is able to relay its location cosmic stations around the world, allowing both ground-based telescopes and space telescopes to observe the burst afterglow. The artificial satellite discovered a SWIFT GRB (Gamma Ray Bursts-), which occurred when the Universe was only in his only 640 million years. It is most likely a hypernova produced by the formation of a black hole in the heart of a giant star of several tens of times the mass of the Sun.

 

The collapse of the heart of the star and its explosion then produces an intense and focused beam of gamma rays by chance directed toward the instruments of SWIFT. This explosion observed in 2009, is the most distant ever observed by scientists. His light has been traveling for 13.1 billion years to reach us. GRB 090423 lasted only 10 seconds but its light has since been observed in many wavelengths, including those of the infrared as in the picture below cons. This event provides an overview of the first moments of the universe and shows that there were already hyper massive stars. The last record redshift, and therefore seniority, was held by the gamma-ray burst of September 2008. It is older than 190 million years. By observing gamma ray bursts can be discovered when the first stars of the universe are on.

Image: The gamma-ray burst GRB 090423 was discovered by SWIFT, April 23, 2009. Just a few degrees of the star η Leonis (constellation Leo) is in 2009, the astronomical event identified, the farthest of the Earth (13.1 billion years). The residual light is observed, as shown in the circle, in the infrared range. credit: Gemini Observatory/NSF/AURA/D.Fox, A. Cucchiara (Penn State Univ.) et E. Berger (Harvard Univ.)

 gamma-ray burst at the beginning of the universe

Burst of gamma rays, GRB 130427A

    

GRB 090423, the gamma-ray burst of 23 April 2009, lasted only 10 seconds, and its light has traveled for 13.1 billion years to reach us. But the gamma burst GRB 130427A April 27, 2013, broke another record. This cosmic dying star explosion, lasted several hours. Gamma-ray bursts are the brightest explosions in the universe and among these hot GRB 130427 is the brightest gamma-ray burst ever seen. It is also the longest duration, Fermi could observe for about 20 hours, a record for this kind of event. The flash traveled for 3.8 billion years before reaching our telescopes. A massive star core short nuclear fuel, collapsed under its own weight and formed a black hole. The black hole triggered jets of particles that have crossed all star and blast into space at nearly the speed of light. This is how we can summarize the gamma-ray burst in April 2013.
The satellite Fermi Large Area Telescope (LAT ), which tracks the sources of gamma rays was miraculously pointed in the right direction at the right time and space telescopes capable of observing were available. The rapid response telescopes operated by the Los Alamos National Laboratory in New Mexico quickly turned to the optical flash that peaked at magnitude 7 on the scale of astronomical brightness, easily visible with binoculars. Gamma-ray Burst Monitor (GBM) on board gamma-ray telescope NASA has captured photon energy giant (95 GeV), which is absolutely huge for a photon.

 

Compared the energy of a photon of visible light is about 2 eV. In the first three seconds of the explosion, the monstrous burst proved to be the most important ever observed. GRB 130427A was the subject of five articles published online on November 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.

nota: The gamma rays are photons of very high energy (beyond 100 keV) sufficient to remove an electron from its orbit. Gamma rays are the most energetic form of light. They have a very short wavelength, less than 5 pico meters, and can be produced by nuclear disintegration, especially in the breasts of massive stars at the end of life. They were discovered by the French chemist Paul Villard (1860-1934).

Image: The gamma flash recorded by Fermi Large Area Telescope (LAT) after the gamma burst GRB 130427A. In the first three seconds of the explosion, the monstrous burst proved to be the most important ever observed. (NASA/DOE/Fermi-LAT collaboration).

 Bouffée de Rayons gamma, GRB 130427A
 
           
Size of the universe
Size of the universe...
 
           
 
1997 © Astronoo.com − Astronomy, Astrophysics, Evolution and Earth science.
Contact    Mentions légales
gravitational lenses
Illusions created by
gravitational lenses...
 
cosmics rays
Cosmic rays and
mutation of species...
 
The hellish journey photon...
The hellish journey of the photon...
 
Recombination in cosmology
Recombination in cosmology...
 
Monocerotis V838, Explosion live image viewed by Hubble
Explosion live image
viewed by Hubble...