This gamma-ray burst is likely to be the brightest burst to hit Earth since the dawn of human civilization.
BOAT GRB and its host galaxy were detected almost edge-to-edge by the Hubble Space Telescope's Wide Field Camera 3 as a strip of light extending to the upper right of the explosion. Images taken on November 8 and December 4, 2022, one and two months after the explosion, are included in this composition.
Researchers say the extragalactic explosion that occurred last October was 70 times brighter than astronomers had seen before. Its light shot toward the inner solar system.
On October 9, 2022, radiation from the explosion, known as GRB 221009A, passed over Earth in a gamma-ray burst (GRB). He left the gamma-ray detectors on several space telescopes with very satisfying information, earning him the nickname BOAT, meaning "the brightest of all time".
For several months after the explosion, astronomers studied the BOAT with multiple instruments to better identify it. And these attempts have only served to further the mythology of the BOAT.
It's just a massive explosion, that's all. The 20th meeting of the High Energy Astrophysics Division of the American Astronomical Society was held in Hawaii on Tuesday, March 28, and Eric Burns, assistant professor of physics and astronomy at Louisiana State University, spoke at a press conference here.
Burns continued: “The BOAT is an event that occurs once every 10.000 years. Therefore, there is a chance that this gamma-ray burst may be the brightest burst to hit Earth since the beginning of human civilization.
The most powerful explosions in the universe are GRBs. They produce more energy in a few seconds than the Sun has produced in its 10 billion years of existence.
Short GRBs, which can last two seconds or less, and long GRBs, which can last for minutes, are two different types that astronomers distinguish. Collisions between neutron stars, superdense stellar remnants, and other objects likely produce the short variety, according to astronomers. On the other hand, most long GRBs are produced by black holes, which are formed when massive stars collapse and die.
“So the center collapses and a black hole is formed. According to Burns, the black hole feeds jets traveling at just below the speed of light.
Burns continued: “As these jets fade, they release their energy as rapid emission of gamma-ray bursts.” The energy accumulated in this star then fuels a supernova explosion. This is followed by what is known as afterglow.
A supernova is expected near the location of BOAT, which is approximately 1,9 billion light-years from Earth. This is because BOAT is a long GRB. But they have yet to discover one, despite using additional instruments and NASA's James Webb and Hubble space telescopes to explore the region.
"If it's there, it's very weak," said Andrew Levan, professor of astronomy at Radboud University in the Netherlands, in a NASA statement Tuesday. It is also possible that the star did not explode, but completely disintegrated inside the black hole, although we would like to continue the search.
Most GRB jets do not sweep the Earth as they are typically quite narrow. However, although intense, these astrophysical events are frequent enough to occur frequently. According to Burns, astronomers have cataloged about 12.000 GRBs so far using information from instruments such as the Russian Konus satellite vehicle and NASA's Fermi Gamma-ray Space Telescope.
He directed a study of GRB records that fully demonstrated BOAT's reliability in brightness. And other research has shown that the extreme brightness is not caused by extremely high-energy jets.
At a press conference Tuesday, Kate Alexander, professor of astronomy at the University of Arizona, said that when we compare the energy in this jet, it is quite similar to the energy of the jets we've seen in previous GRBs.
Then why was it so bright? He loved it. “It turned out that all the energy of this jet is concentrated at a relatively small angle. Therefore, every particle moving in this jet was focused in a very, very narrow beam that was directed towards Earth.
The BOAT's jet was like the stronger spray you get when you use a restrictive nozzle, and by comparison the effect was like a garden hose.
The components of a long gamma-ray burst, the most typical type, are shown in this image. The core of a massive star collapsed (left), creating a black hole that spewed particles into space at nearly the speed of light. Radiation in the spectrum is produced by the hot, ionized gas near the developing black hole, by collisions between rapidly moving gas shells inside the jet, and by the leading edge of the jet as it swept and interacted with its surroundings. (external shock).
A few months ago, the source region had shifted behind the Sun as viewed from Earth, forcing astronomers to delay some of their BOAT observations. But this region is starting to resurface, and researchers are prepared.
Levan said during Tuesday's teleconference that "more observations will be made in the coming weeks and months, including Hubble and Webb."
He and several other academics are particularly interested in finding out whether BOAT produced a supernova.
“Watch this space for what we hope is a more definitive answer,” Levan said in the statement.
These and other BOAT findings are published by the researchers in a special issue of The Astrophysical Journal Letters.
source: space.com
Günceleme: 29/03/2023 20:55