Fast radio bursts (FRBs) are brief flashes of radio waves from distant galaxies that are probably emitted by neutron stars. Some FRBs repeat, which enables follow-up observations to constrain their local environments. Now, astronomers have observed more than a hundred bursts from the source of FRB 20190520B, of which 13 were bright enough to measure the polarization; the fluctuating polarization properties indicate that the magnetic field close to the FRB 20190520B source was highly variable, twice reversing direction.
“Our findings bring us closer to solving the enigma of FRBs and help us to uncover new insights into some of the most extreme environments in the Universe,” said Dr. Shi Dai, an astronomer at Western Sydney University, the National Astronomical Observatories at the Chinese Academy of Sciences and CSIRO.
“We know that FRBs originate from sources in distant galaxies. This makes FRBs unique tools to probe a range of astrophysics, such as missing matter in between galaxies, the expansion of the Universe, and astrophysics in dense and highly magnetised environments.”
Dr. Dai and colleagues observed the repeating FRB 20190520B over a 17-month period using CSIRO’s Parkes radio telescope and the Green Bank Telescope.
They found that the source of FRB 20190520B is surrounded by dense plasma that is not only highly magnetised but also highly turbulent, with the direction of the magnetic field changing twice during this period — a phenomenon never observed before.
“FRB 20190520B is one of a rare class of FRBs found to repeat,” Dr. Dai said.
“First discovered by the FAST telescope, FRB 20190520B is not only active but more importantly can be detected over a wide radio frequency window, which enables us to use the most advanced radio instruments, such as Parkes and its ultra-wideband receiver, to carry out detailed studies.”
Over the course of the study, the astronomers detected more than 100 bursts from FRB 20190520B, and successfully…
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