‘No way, that can’t be right’: Possible answer to strange fast radio bursts

10 Jan 2018

Image: Falkovskyi/Shutterstock

A team of astrophysicists has found a possible origin for mysterious fast radio bursts, but it came as a complete shock.

One of 2017’s perplexing astronomical mysteries involved the discovery of at least 15 fast radio bursts (FRBs) – bright pulses of radio emission with no known origin. This resulted in speculation that they might be attempted contact from extraterrestrials.

While this is very unlikely to be the case, a team of researchers in the US has found what it believes to be the ‘extreme’ source of the bursts, offering potential clues as to what might be causing them.

In a paper published to Nature, the team revealed that the only known repeating FRB source is in an environment among the most highly magnetised regions of space ever observed.

Until now, such extremes had only been observed around supermassive black holes, but the immensely magnetised region could also be the result of a combination of other extreme astrophysical circumstances.

“I had to read my email a few times to really digest it. I kept thinking, ‘No way, that can’t be right,’” said Victoria Kaspi, director of the Canadian Institute for Advanced Research’s gravity and extreme universe programme.

“We found something that is clearly in an extreme place, and the extreme location may create a phenomenon that is one of the biggest astrophysical mysteries of recent times.”

FRB 121102 has been noted as being particularly unusual because it is the only known repeating burster and the first FRB to be pinpointed in the sky.

While located at a distance of 3bn light years away, the researchers were able to catch a glimpse inside its environment by examining the polarisation of its radio emission in detail, through a phenomenon known as the Faraday effect.

The leading hypothesis

The team’s leading hypothesis of how this particular region of space could be so extreme is that it contains a black hole 10m to 100m times the size of our sun.

As a neutron star nears the supermassive black hole, it produces huge magnetic fields, or even shoots out hot, ionising gas.

Other possibilities include a ultra-highly magnetised wind nebula, created by winds from a pulsar; or it could be caused by the remnants of an ultra-highly magnetised supernova, powered by a young neutron star.

“If you have an extreme object in an extreme environment, is that just a coincidence?” Kaspi asked.

“FRBs have these huge explosions in radio waves and we don’t know why that occurs. Maybe this is a clue to the mechanism that produces these explosions.”

Colm Gorey was a senior journalist with Silicon Republic