(ORDO NEWS) — In September 2021, NASA’s Neil Gerrel Swift Observatory noticed a powerful explosion – a gamma-ray burst (GRB) that occurred in the early universe.
The object now known as GRB210905A looks the same as it did when the universe was young, as it took 12.8 billion years for its light to reach Earth.
As the intense light from the gamma-ray burst fades quickly, as does its afterglow, astronomers rushed to capture what was left with a few instruments at the very large telescope at the European Southern Observatory in Chile and a few more instruments.
How does a gamma ray “live”
Gamma radiation comes from certain types of particle collisions and from the nuclear decay of radioactive substances (which is one of the reasons why nuclear waste is so infamously dangerous).
Astronomers believe that flashes of these powerful electromagnetic rays appear in the darkness of space at least once a day, but they do not linger for long.
While gamma-ray bursts are visible, astronomers carefully measure how much light the flash emits at different wavelengths.
Like all light sources in space, as the wavelengths of light are stretched out in the void, the GRB signal shifts towards the red end of the spectrum.
The amount of signal change, called redshift, reflects how far away the source is, with very distant signals often becoming infrared light.
How do we capture such outbreaks
While the human eye can’t see infrared light, an instrument like the X-Shooter can, and that’s how the researchers figured out the object’s distance and the length of time it took for its light to reach Earth.
Such distant objects are usually difficult to observe because they are often faint, but gamma-ray bursts such as GRB210905A are extremely bright and can be detected if caught and photographed fairly quickly.
Gamma-ray flashes at this distance are rare events… but they are only a small part of a larger population that future proposed missions promise to detect, said team leader Andrea Rossi.
The nature of gamma ray bursts
So where do these mysterious bursts of light come from? The researchers believe that the GRB received its light shock from material being pulled in by the black hole’s giant gravity.
The scientists ruled out the possibility that the signal came from a magnetar – a very compact, dead core of a massive star with enormous magnetic energy – because GRB210905A had too much energy for the magnetar to handle.
The more information about gamma-ray bursts is revealed, the more can be learned about what the universe was like when it was young.
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