/Astronomers Unveil New – and Puzzling – Features of Mysterious Fast Radio Bursts

Astronomers Unveil New – and Puzzling – Features of Mysterious Fast Radio Bursts

Key idea:  New study by international team of scientists reveals an evolving, magnetized environment and surprising source location for deep-space fast radio bursts – observations that defy current understanding.

Original author and publication date: Tony Allen (University of Nevada, Las Vegas) – September 21, 2022

Futurizonte Editor’s Note: One day, perhaps soon, we will receive an unmistakable intelligent signal from space. Will we be intelligent enough to recognize it?

From the article:   

Fast radio bursts (FRBs) are millisecond-long cosmic explosions that each produce the energy equivalent to the sun’s annual output. More than 15 years after the deep-space pulses of electromagnetic radio waves were first discovered, their perplexing nature continues to surprise scientists – and newly published research only deepens the mystery surrounding them.

In the Sept. 21 issue of the journal Nature, unexpected new observations from a series of cosmic radio bursts by an international team of scientists – including UNLV astrophysicist Bing Zhang – challenge the prevailing understanding of the physical nature and central engine of FRBs.

The cosmic FRB observations were made in late spring 2021 using the massive Five-hundred-meter Aperture Spherical radio Telescope (FAST) in China. The team, led by Heng Xu, Kejia Lee, Subo Dong from Peking University, and Weiwei Zhu from the National Astronomical Observatories of China, along with Zhang, detected 1,863 bursts in 82 hours over 54 days from an active fast radio burst source called FRB 20201124A.

“This is the largest sample of FRB data with polarization information from one single source”, said Lee.

Recent observations of a fast radio burst from our Milky Way galaxy suggest that it originated from a magnetar, which is a dense, city-sized neutron star with an incredibly powerful magnetic field. The origin of very distant cosmological fast radio bursts, on the other hand, remains unknown. And the latest observations leave scientists questioning what they thought they knew about them.

“These observations brought us back to the drawing board,” said Zhang, who also serves as founding director of UNLV’s Nevada Center for Astrophysics. “It is clear that FRBs are more mysterious than what we have imagined. More multi-wavelength observational campaigns are needed to further unveil the nature of these objects.”

What makes the latest observations surprising to scientists is the irregular, short-time variations of the so-called “Faraday rotation measure”, essentially the strength of the magnetic field and density of particles in the vicinity of the FRB source. The variations went up and down during the first 36 days of observation and suddenly stopped during the last 18 days before the source quenched.

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