FRBs are the brightest astronomical transient data of a millisecond in radio bands of unknown origin. Less than five percent of what has ever been found has been observed to recur and only a few are persistently active. Using the Five Hundred Meter Global Radio Telescope (FAST), also known as the China Sky Eye, an international team of astronomers from the National Academy of Astronomical Observatories under the Chinese Academy of Sciences (NAOC) discovered and spotted an active 20190520B in a metal-poor dwarf galaxy nearly three billion light-years from Earth. Subsequently, telescopes including the Very Large Array, the Palomar Telescope, the Keck Telescope, the Subaru Telescope, and the Canada-France-Hawaii Telescope continued their observations, respectively, to confirm FRB 20190520B. The scientists said that the FRB 20190520B appears to be in an intricate plasma environment that resembles that of an ultra-bright supernova, suggesting that it may be a “newborn”. It is the second example of a highly active FRB with repetitive explosions and persistent radio emission between explosions coming from a solid area, following the discovery of the first FRB 20121102A repeater in 2016, according to a study published Wednesday in the journal Nature. The differences between the two FRBs and all the others imply the possibility that there are two different types of FRBs, the researchers said. Candidates for FRB sources are now the ultra-dense neutron stars that remain after the explosion of a huge star called a supernova, or neutron stars with extremely strong magnetic fields, called magnets. The astronomers said that there may be either two different mechanisms or that the objects that produce them act differently at different stages of their evolution. “We further assume that FRB 20121102A and FRB 20190520B represent the initial stage of an evolving FRB population,” Li Di’s co-correspondent with the NAOC said. “A coherent picture of the origins and evolution of FRBs is likely to emerge in just a few years,” Lee said. Located in a naturally deep and round karst cavity in southwest China’s Guizhou Province, FAST officially launched in January 2020 and officially opened to the world on March 31, 2021. It is believed to be the most sensitive radio telescope in the world.
