Fast radio bursts (FRBs) are millisecond cosmic bursts that each produce an energy equivalent to the Sun’s annual output.

More than 15 years after the first discovery of electromagnetic radio wave pulses from outer space, their perplexing nature continues to surprise scientists – and recently published research only deepens the mystery surrounding them.

Published in Nature, unexpected new observations of a series of fast cosmic radio bursts by an international team of scientists – including UNLV astrophysicist Bing Zhang – challenge the prevailing understanding of the physical nature and central driver of FRBs. uri.

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 of Peking University and Weiwei Zhu of the National Astronomical Observatories of China, along with Zhang, detected 1,863 bursts in 82 hours over 54 days from a source active fast radio burst called FRB 20201124A.

The origin of the fast radio wave bursts remains unknown

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

Observations of a fast radio burst in our Milky Way galaxy suggest that it originated from a magnetar, which is a dense, city-sized neutron star with an incredibly strong magnetic field.

On the other hand, the origin of very distant cosmological fast radio bursts remains unknown. And the latest observations are making scientists question what they thought they knew about them.

What makes the latest observations surprising to scientists are the erratic, short-lived variations in the so-called “Faraday rotation measure,” which represents the magnetic field strength and particle density in the vicinity of the FRB source.

The variations rose and fell during the first 36 days of observation and stopped abruptly during the last 18 days before the source died out.

The observations puzzled astronomers

“Such an environment is not directly expected for an isolated magnetar. Something else could be in the vicinity of the FRB engine, possibly a binary companion,” Zhang added, according to the report

To observe the FRB’s host galaxy, the team also used the 10m Keck telescopes located at Mauna Kea in Hawaii. Young magnetars are thought to reside in the active star-forming regions of a star-forming galaxy, but the optical image of the host galaxy shows that—unexpectedly—the host galaxy is a metal-rich spiral galaxy, such as Our Milky Way. The FRB location is in a region where there is no significant star formation activity.

“This location is not consistent with a young central magnetic engine formed during an extreme outburst, such as a long gamma-ray burst or a superluminous supernova, the widely speculated progenitors of active FRB engines,” Dong said.

The study was published in the journal naturally.

Leave A Reply