NASA urmareste cea mai puternica si indelungata explozie cosmica observata pana in prezent, care are loc intr-o galaxie indepartata.
Pentru a putea observa puternica explozie, NASA a a mobilizat mai multe telescoape, printre care si telescopul orbital Hubble, iar astronomii au spus ca nu au vazut niciodata o explozie de o intensitate luminoasa atat de variabila si de o durata atat de lunga.
Potrivit specialistilor, in general, puternicele emisii de radiatii gamma ce rezulta din explozia unei supernove nu dureaza mai mult de cateva ore.
"Cunoastem obiecte din galaxia noastra ce pot produce explozii in lant sau repetate, insa acestea ar fi de milioane de ori mai slabe decat explozia pe care o observam acum.
Este cu adevarat extraordinar", a sustinut Andrew Fruchter, astronom la Space Telescope Science Institute din Baltimore, citat de Hotnews.ro.
Fenomenul cosmis a fost semnalat pentru prima data in 28 martie, sursa acestei explozii fiind localizata in constelatia Dragonului, in centrul unei galaxii situate la 3,8 miliarde de ani lumina de Pamant.
Explozie cosmică de o putere şi durată ce nu a fost niciodată observată până în prezent / FOTO: spacetelescope.org
Cercetatorii sunt de parere ca este vorba despre explozia unei stele ce a trecut prea aproape de o gaura neagra din centrul galaxiei. Forta gravitationala imensa exercitata de aceasta gaura neagra a prins probabil o stea supermasiva care este in prezent consumata treptat.
This mosaic image illustrates how NASA's Swift satellite, Hubble Space Telescope, and Chandra X-ray Observatory teamed up to study one of the most puzzling series of cosmic blasts ever observed.
On March 28, 2011, Swift's Burst Alert Telescope discovered the source of rapid gamma-ray and X-ray emissions flaring up in the direction
of the constellation Draco.
It was cataloged as GRB 110328A. (The orange starburst pattern is an artifact of Swift's imaging system.)
Hubble's high resolution was used to pinpoint the source of the explosions at the center of a dwarf galaxy, which lies 3.8 billion light-years away from Earth.
These observations were made on April 4.
On April 4, a Chandra X-ray image located the X-ray source 10 times more precisely than Swift did. The data show that the source lies at the center of the galaxy Hubble imaged.
These combined data support the hypothesis that the extraordinary and unusual blasts likely arose when a star wandered too close to its galaxy's central black hole. Intense tidal forces tore the star apart, and the infalling gas continues to stream toward the hole. According to this model, the spinning black hole formed an outflowing jet along its rotational axis. A powerful blast of X-rays and gamma rays is seen when the jet is pointed in our direction.
A Cosmic Mystery NASA/Swift/Stefan Immler
A mystery is unfolding out there in the cosmos, and NASA’s Swift, Hubble Space Telescope, and Chandra X-Ray Observatory are teaming up to solve the case. But while researchers have pieced together some of the pieces of the puzzle over the last week, the huge, high-energy blast continues to brighten and fade, making it the brightest, longest-lasting such burst of energy researchers have ever seen.
It all started when Swift’s Burst Alert Telescope picked up a powerful gamma-ray burst on March 28, at which point it notified scientists the world over. Astronomers sometimes see gamma-ray bursts like this when a star dies, but these bursts generally last a few hours or less.
The plot thickened when the burst didn’t fade away. Dozens of telescopes turned toward the enigma, and it was concluded that the source of the gamma-ray burst is at the center of a galaxy some 3.8 billion light-years away. The burst was still repeating itself, brightening and fading over and over. There are objects in our own galaxy known to produce such repetitive bursts, but at a fraction of the intensity.
However, the gamma-ray burst’s location at the center of a galaxy does point toward one likely suspect: a black hole.
So astronomers now have a theory. It’s quite possible that a star was minding its own business when it wandered too close to the galaxy’s central black hole. The intense forces generated by the black hole began to tear the star apart, causing infalling gas to begin streaming into it in a particle jet. This spawned an outflowing jet along the black hole’s rotational axis, and that jet is pointed directly at us from billions of light years away.[NASA]
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