Recently, a group of scientists managed to record star explosion largest in the universe. This event is the most energetic radiation and the longest gamma-ray burst of the gamma-ray burst (GRB).
Gamma rays in the universe are associated with the collapse of fast-rotating massive stars into black holes. They are categorized into two distinct phases: a chaotic initial phase that lasts for tens of seconds and an afterglow phase that fades smoothly.
Using a special observatory in Namibia, scientists watched the GRB phenomenon. The event, dubbed GRB 190829A, is one of the closest gamma-ray bursts observed so far, with a distance of about a billion light years.
According to the research team, explosion it likely marks the moment when a large star dies in a supernova explosion and begins its transition into a black hole.
The Fermi and Swift telescopes detected the event on August 29, 2019 in the constellation Eridanus. Scientists then immediately caught the remnants of the explosion when it was spotted by the HESS telescope.
“We were able to determine the spectrum of GRB 190829A to an energy of 3.3 tera-electronvolts, about a trillion times more energetic than a photon of visible light,” said one of the researchers, Edna Ruiz-Velasco of the Max Planck Institute for Nuclear Physics in Heidelberg.
“That’s what’s so remarkable about these gamma-ray bursts. They occur in our cosmic backyard where very high-energy photons are not absorbed in collisions with the backlight on their way to Earth, as happens at greater distances in the cosmos.” he explained.
After following the afterglow for more than three days, scientists discovered surprising similarities between the X-ray emission and the very high-energy gamma-ray emission from the remnants of the explosion.
Another researcher, Sylvia Zhu of the DESY Science Communication Lab, said established theories assume that a separate mechanism must produce two emission components: the X-ray component comes from ultra-fast electrons reflected in the strong magnetic field of the Sun.
“This synchrotron process is very similar to how particle accelerators on Earth produce bright X-rays for scientific investigations,” he said.
Existing theory suggests that electrons in gamma-ray bursts collide with synchrotron photons and increase them to gamma-ray energy in a process called Compton self-synchronization.
But observations of GRB 190829A’s light now show that both components, X-rays and gamma rays, fade in synchrony. Also, the gamma-ray spectrum matches the extrapolation of the X-ray spectrum. This means that the very high energy X-rays and gamma rays in this glow are produced by the same mechanism.
This finding is very meaningful for scientists because it opens the opportunity to be able to detect explosion future gamma rays. Next-generation instruments such as the Cherenkov Telescope Array currently under construction in the Chilean Andes and on the Canary Island of La Palma, hold great promise for doing so.