Gamma ray bursts (GRBs) are the most violent and energetic explosions in the Universe. For the short period of time they are visible (generally less than Gamma-ray bursts are among the most energetic and explosive events in the universe. They are also short-lived, lasting from a few. The Neil Gehrels Swift Observatory is a space telescope that searches for gamma-ray bursts.
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GAMMA RAY BURSTS PDF
In the early s, military satellites monitored our planet for violations of the Gamma ray bursts Test Ban Treaty.
Rogue nuclear tests would show up as gamma ray flashes coming up from the ground.
While flashes were detected, they did not originate on Earth! Hundreds of bursts were recorded for decades but their nature remained a mystery.
Gamma-ray burst - Wikipedia
Because gamma gamma ray bursts are very difficult to focus, it was impossible to pinpoint their locations on the sky. Also, their ephemeral nature gamma ray bursts them maddeningly tricky to investigate.
By the time a telescope could be pointed in the direction of a flash, it was too late. Some researchers speculated they might be engineered by advanced civilizations!
This map shows the locations of all these on the sky. The fact that they are not confined to the plane of our galaxy tells astronomers that GRBs must be extragalactic in nature.
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The colors differentiate the brightness of the bursts. They were definitely not local.
GRBs in the Milky Way would have been seen mostly in the thin plane of our galaxy—the Compton X-Ray Observatory found that gamma ray bursts came from all over the sky. Astronomers realized they must be extragalactic. Better telescopes which quickly pinpointed the precise location of a GRB led to the detection of faint afterglows all across the electromagnetic spectrum.
In every case, the Gamma ray bursts came from the same direction as a very distant galaxy. These galaxies tended to be young, active stellar nurseries — the perfect place to build very massive stars. The afterglow light revealed gamma ray bursts lot more.
By measuring how much the light had been redshifted by the expansion of the universe, astronomers could estimate their gamma ray bursts. And they were most definitely not local. The light from GRBs had been traveling for over half the age of the universe—they were among the most distant objects ever seen.
But to be so far away and still be the brightest thing in the sky meant an unimaginable amount of energy had to be producing these flashes.
In fact, the amount of energy needed was equivalent to converting all the mass in the sun to pure radiation in a matter of seconds. Gamma ray bursts even a supernova can do that.
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You would need something even more powerful—a hypernova! An extraordinarly massive dying star can collapse its core into a black hole without triggering a supernova. With the sudden removal of the stellar core, the upper layers of the gamma ray bursts come crashing down to fill in the cavity.
If the star is spinning rapidly, the infalling material is whipped up into a swirling frenzy. A disk forms deep inside the star. In the ensuing vortex, superheated plasma gamma ray bursts ensnared by highly twisted magnetic fields.