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A gamma ray burst about 2.4 billion light years away is being called “the
BOAT” – the brightest of all time – and is so powerful it has even affected
Earth’s atmosphere.
Astronomers have spotted what may be the most powerful explosion ever seen.
The gamma ray burst, called GRB221009A, was spotted on 9 October, and even
its afterglow is brighter than most objects in the sky.
This type of gamma ray burst (GRB) is thought to occur when a massive star
explodes in a supernova, leaving behind a black hole. The explosion creates
an extraordinary jet of light which makes up the GRB itself, and then the
supernova causes a dimmer afterglow. This particular GRB appears so bright
partially because it is about 2.4 billion light years away from Earth,
making it one of the closest GRBs ever spotted in addition to being the
brightest.
“If we look at all of the gamma ray bursts that have been detected, this one
stands apart,” says Jillian Rastinejad at Northwestern University in
Illinois. “Informally, we’ve been calling it the BOAT – the brightest of all
time.” She and her colleagues calculated that a GRB this bright is expected
to occur only once every thousand years or so.
We don’t know exactly how powerful this burst is, though, despite the fact
that many telescopes around the world are looking at it. That is partially
because it is so bright that it saturates the detectors of gamma-ray
telescopes, so all they see are completely white pixels with no detail, says
Andrew Levan at Radboud University in the Netherlands, one of Rastinejad’s
colleagues. “If you had gamma-ray eyes, you’d be blinded,” he says. Current
estimates put the energy of the GRB between 10^54 and 10^55 ergs, he says –
in contrast, the total energy released by the sun throughout its lifetime is
expected to be about 10^51 ergs.
GRB221009A is so bright that it is affecting Earth, even from billions of
light years away. Naval radio transmitters recorded a strange disturbance in
the upper atmosphere, which seems to have been caused by the powerful light
from the GRB slamming into it. Detectors that search for high-energy photons
– particles of light – have also seen extraordinary particles with energies
far higher than anything produced at the Large Hadron Collider.
This has made a splash among astronomers. “It seems like pretty much every
telescope in the world is starting to look at it,” says Rastinejad. But to
learn more about the supernova itself and its home galaxy, they will have to
wait until the bright jet fades, which could take months. Once that occurs,
we should have a better idea of why this GRB was so extraordinarily bright.
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Space & Astrophysics