Accurate Detection of the Brightest Gamma Ray Burst by "Wisdom Eye" and "Polar Eye"
2023-03-30
At 2:00 a.m. on March 29, Beijing time, the Institute of High Energy Physics of the Chinese Academy of Sciences (hereinafter referred to as the "Institute") and more than 40 scientific research institutions around the world jointly released the research results of GRB221009A, the brightest gamma ray burst (hereinafter referred to as the "gamma ray burst") so far. GRB221009A was produced by the collapse and explosion of a massive stellar core, with its "birthplace" located in the depths of the universe 2.4 billion light years from Earth. Due to its extreme brightness and relatively close proximity to the Earth, high-energy astrophysicists have defined it as a historic event that occurs once in a thousand years. The "Insight HXMT" satellite and the "Polar Eye" space telescope (GECAM-C) led by the Institute of High Energy have successfully measured the instantaneous radiation and early afterglow of the gamma storm with the highest international accuracy in the hard X-ray and soft gamma energy bands. Gamma bursts are the most violent explosive phenomena after the Big Bang, including two types: a core collapse explosion that occurs in a massive star, usually lasting longer than 2 seconds; The other type occurs when two extremely dense celestial bodies (neutron stars, black holes, etc.) merge and explode, usually lasting less than 2 seconds, and simultaneously emit gravitational waves. These two types of celestial explosions can produce an extremely dense object such as a black hole or neutron star, which engulfs surrounding matter through extremely strong gravity and ejects matter from both poles at a speed close to the speed of light, forming a pair of opposing jets. Processes such as shock waves or magnetic reconnection within the jet accelerate charged particles to produce gamma ray radiation, known as transient radiation. The interaction between the jet and the surrounding interstellar medium can also generate radiation, known as afterglow. Only when the jet is precisely aimed at the Earth will humans have a chance to detect these radiation. Based on accurate observation data from the Polar Space Telescope, scientists have found that GRB221009A has increased the brightness record of gamma storms by 50 times. One of the corresponding authors of the paper Xiong Shaolin, a researcher at the Institute of High Energy, said, "Assuming that a gamma storm radiates almost the same amount of gamma rays in all directions, then based on the data we detected, we can calculate the total energy of all gamma rays emitted by the gamma storm in all directions, that is, isotropic energy. It is also found to have broken records, exceeding 10 to the 55th power grid, equivalent to releasing all energy of 8 solar masses in one minute!" The joint observation results of "Polar Eyes" also provide a new perspective for in-depth understanding of this extreme cosmic explosion phenomenon - one of the corresponding authors of the article Professor Zhang Bing from the University of Nevada, Las Vegas, USA, said, "It can be speculated that the inflection of the afterglow of the gamma storm from slow decay to fast decay occurred very early, which means that the jet generating gamma rays is very narrow, and is one of the narrowest gamma storm jets detected by humans." The research team believes that this may be one of the reasons why the gamma storm appears extremely bright. This work was completed by an international cooperation team led by the Key Laboratory of Particle Astrophysics of the Chinese Academy of Sciences, with members from more than 30 research institutions in China, the United States, Italy, France, Germany, etc. The person in charge of the Institute of High Energy introduced that in addition to space observation, the Institute of High Energy led the construction of high altitude cosmic ray observation
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Source:GMW.cn
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