An international team of astronomers recently observed more than 1,650 rapid radio bursts (FRBs) detected from a source in deep space, representing the largest set – by far – of mysterious phenomena on record.
More than a decade after the discovery of FRBs, astronomers are still bewildered by the origins of the millisecond cosmic explosions that each produce energy equivalent to the sun’s annual output.
In a study published in the Oct. 13 issue of the journal Nature, scientists – including UNLV astrophysicist Bing Zhang – report the discovery of a total of 1,652 independent FRBs from one source during 47 days in 2019. The source, dubbed FRB 121102, was observed using the Five Hundred Meter Aperture Spherical Telescope (FAST) in China, and represents more FRBs in an event than all previously reported events combined.
“This was the first time that an FRB source has been studied in such detail,” said Zhang, one of the study’s corresponding authors. “The large set of gusts has helped our team better understand the characteristic energy and energy distribution of FRBs, which sheds new light on the engine that powers these mysterious phenomena.”
Since FRBs were first discovered in 2007, astronomers around the world have turned to powerful radio telescopes like FAST to trace bursts and search for clues to their origin and production. The source that powers most FRBs are widely believed to be magnetars, incredibly dense, city-sized neutron stars that have the strongest magnetic fields in the universe. And while scientists gain clarity on what produces FRBs, the exact location where they occur is still a mystery.
A mystery that the recent results may be starting to unravel.
According to Zhang, there are two original active models of FRBs. One could be that they originate in magnetospheres, or in the strong magnetic field of a magnetar. Another theory is that FRBs form from relativistic shocks outside the magnetosphere traveling at the speed of light.
“These results pose great challenges to the latter model,” explains Zhang. “The bursts are too frequent and – given that this episode alone represents 3.8% of the energy available from a magnetar – it is too much energy for the second model to work.”
The bursts were measured by FAST over a total of 59.5 hours over 47 days from August 29 to October 29, 2019.
âDuring its most active phase, FRB 121102 consisted of 122 bursts measured over a one hour period, the highest repetition rate ever seen for an FRB,â said Pei Wang, one of the lead authors. from the article from the Chinese Academy’s National Astronomical Observatories. of Science (NAOC).
Researchers expect FAST to continue to systematically investigate large numbers of repetitive FRBs in the future.
âAs the largest antenna in the world, the sensitivity of FAST proves to be conducive to revealing the intricacies of cosmic transients, including FRBs,â said Di Li, principal investigator of the study at NAOC.
The study includes more than 30 co-authors from 16 institutions in four countries and is part of a long-standing collaboration between institutions. In addition to UNLV and NAOC, collaborating institutions include Guizhou Normal University, Cornell University, Max Planck Institute for Radio Astronomy, University of West Virginia, CSIRO Astronomy and Space Science, University of California at Berkeley and Nanjing University.
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