Astronomers deduce the origins of a fast radio burst based on 2,000 burst observations

Astronomers observed nearly 2,000 bursts from a fast radio burst (FRB) called FRB 20201124A, a press statement reveals. Using a computer model to analyze the bursts, they found that they might have originated from a complex magnetized site.

The new findings, published in the journals Nature and Nature Communications, could help the global astronomical community to better understand these types of sites and how they may produce FRBs. Their work could help to map out and better understand one of the great mysteries of astronomy.

Investigating a fast radio burst

Fast radio bursts are pulses of radio-frequency electromagnetic radiation. Several hundred FRBs have been found since the first one was discovered in 2007. The nature of the phenomena is shrouded in mystery, leading some to speculate they may originate from intelligent extraterrestrial civilizations.

Recently, observations of a Galactic fast radio burst from inside the Milky Way suggested some of the phenomena originate from magnetars, a type of neutron star with an incredibly powerful magnetic field. However, the origin of cosmological FRBs, which are observed at a massive distance from Earth, remains unknown.

In the Nature paper, astronomer Kejia Lee and a team detailed how they used the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in China to observe FRB 20201124A. They detected 1,863 bursts over the course of 82 hours spread out over 54 days. According to the scientists, the high rate of bursts makes their target one of the most active FRBs observed to date.

The researchers observed irregular, short-time variation of magnetic field strength of separate bursts during the first 36 days of monitoring the FRB. After that point, they noted a constant Faraday rotation measure — used to measure magnetic field strength.

Their findings provide evidence of a complex magnetized region of space located within an astronomical unit (the distance between the Earth and the Sun) of the FRB source. The team of astronomers also noted a few important observations regarding the region of the Milky Way-sized, metal-rich galaxy where the FRB is located. They pointed out that the region has a low stellar density and that it would be unusual for a young magnetar — formed during the explosion of a star — to be located in that region.

New targets for future observations

In the separate Nature Communications paper, Fayin Wang and colleagues present a physical model that explains the observed characteristics of the FRB.

Based on the findings from their model, they suggest the bursts come from a binary system featuring a magnetar and a star that's larger and rotates faster than the Sun.

They suggest future FRB detection efforts should seek out similar binary systems. Put together, both papers shed new light on the mysterious origin of FRBs. It's part of a massive collective effort aimed at mapping and better understanding the intricacies of our vast, expansive universe.