Chinese scientists at the Institute of High Energy Physics (IHEP) under the Chinese Academy of Sciences (CAS) have discovered a gamma ray burst with an energy of up to 37 million electron volts from an exceptionally bright gamma-ray burst, Interesting Engineering reported on July 25. This represents the highest energy spectral line emitted by celestial bodies in the universe.
This explosion is approximately 2.4 billion light-years away from us.
The explosion, named GRB 221009A, originated from the constellation Sagittarius, around 2.4 billion light-years away. Despite this vast distance, it was so bright that it “temporarily blinded” some cosmic observation equipment and disrupted the atmosphere of our blue planet, according to research published in the Astrophysical Journal Letters on March 29.
This event immediately attracted the attention of the international astrophysics community. They estimate that such a fierce and brilliant event occurs only once in a millennium, making it a rare opportunity to study the origins and evolution of gamma-ray bursts (GRBs).
GRBs are believed to be the most powerful explosions in the universe after the Big Bang. They originate from extremely massive star explosions or supernovae, when a giant star runs out of fuel and collapses into a neutron star or black hole.
Simulation of the gamma-ray burst GRB 221009A. (Video: NASA/Swift/Cruz deWilde).
The Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences, along with scientists from over 30 organizations from the United States, Italy, France, and Germany, accurately measured the prompt emission and afterglow of this unprecedented explosion using the Insight-HXMT and GECAM-C space telescopes.
Researchers from IHEP, the Yunnan Observatory under CAS, Hebei Normal University, and Guizhou Normal University conducted a thorough analysis of observational data from two gamma-ray detectors in space: GECAM-C and Fermi/GBM. GECAM-C, funded by CAS, accurately measured the low-energy spectral range of this GRB, while Fermi/GBM monitored the high-energy range where the gamma-ray burst occurred. Notably, the gamma-ray burst was so bright that the Fermi/GBM detector lost data, complicating data analysis. GECAM-C did not encounter such issues due to its equipment design. Thus, GECAM-C data was used to calibrate the Fermi/GBM data.
After conducting a thorough analysis of the two data sources, accounting for equipment effects and modeling, the research team obtained the spectrum of the GRB. They also identified a series of gamma-ray emissions from the burst, including emissions with energies of 37 million electron volts. According to IHEP, this discovery highlights the unique aspects of GRB physics and their relativistic jets (huge streams of matter propelled to nearly the speed of light and extremely hot).
Prompt emission refers to the initial phase with the strongest intensity of gamma-ray emissions, typically lasting a few seconds, and can be used to pinpoint the location of the explosion, while afterglow refers to the longer-lasting, less intense emission that follows the prompt emission.
Simulation of the brightest gamma-ray burst GRB 221009A reaching Earth. (Photo: Global Times).
The research team discovered that within one minute, the GRB 221009A explosion released energy equivalent to that of 10,000 suns over their billion-year lifetimes through nuclear fusion reactions.
According to the lead author of the study, Xiong Shaolin at IHEP, investigator for the GECAM-C project, the measurements of GRB 221009A broke the previous brightness record of gamma-ray bursts by 50 times.
Since the discovery of GRBs in 1967, scientists have identified nearly 10,000 such events, caused by the collapse of massive stars or the collision of high-density celestial bodies, such as black holes and neutron stars.
“What makes GRB 221009A special is that it is not only extremely bright, but the explosion also emitted a very narrow beam of radiation directed straight towards Earth, allowing us to witness its afterglow”, Xiong noted.
Zhang Shuangnan, the principal investigator of the Insight-HXMT project and a researcher at IHEP, added that if an explosion like GRB 221009A were to occur within the Milky Way and its beams of radiation were directed toward Earth, it would be catastrophic.
“The global scientific community is fortunate to have captured this powerful event. The next time we witness a similar gamma-ray burst, humanity may have evolved into an interstellar civilization”, emphasized Zhang Bin, an astrophysics professor from the University of Nevada, USA.
