Scientists find source of mysterious ‘fast radio bursts’ being sent to Earth

Scientists have found the source of a number of intense radio blasts that have been detected on Earth.

The signals, known as “fast radio bursts”, are intense but very short: they last less than a second but contain more energy that the Sun puts out in a whole year.

They were first discovered in 2007 but have remained largely mysterious since, even as researchers have catalogued up to 1,000 of them in the years since. The extremity of the blasts have led to speculation that they are the result of everything from extraterrestrial technology to unknown physical phenomena.

But, in the new study, researchers tracked down the source of eight of those bursts to their exact locations. Five of them were found within spiral galaxies, placed along the their outstretched curvy tentacles.

That discovery not only helps the search for the location of the blasts, but their cause too – the discovery helps narrow down the possible explanations.

“We don’t know what causes FRBs, so it’s really important to use context when we have it,” said Northwestern’s Wen-fai Fong, a co-author of the study. “Because spiral arms are signs of stars being born, this was a surprise, offering a major clue that FRBs must correlate with star formation.”

The new research, conducted using the Hubble Space Telescope and by astronomers from a range of institutions, is accepted for publication in The Astrophysical Journal. An early version is published on ArXiv.org.

“Our results are new and exciting. This is the first high-resolution view of a population of FRBs, and Hubble reveals that five of them are localized near or on a galaxy’s spiral arms,” said Alexandra Mannings of the University of California, Santa Cruz, the study’s lead author.

“Most of the galaxies are massive, relatively young, and still forming stars. The imaging allows us to get a better idea of the overall host-galaxy properties, such as its mass and star-formation rate, as well as probe what’s happening right at the FRB position because Hubble has such great resolution.”

The study seems to rule out suggestions that they the bursts come from the deaths of the youngest and most massive stars. It also seems to indicate they are not coming from the merging of neutron stars, which are the crushed cores of stars that die in supernovae, since the galaxies they were spotted in are too young and such stars tend not to be found on a spiral galaxy’s arms.

It does however suggest that the primary theory about fast radio bursts or FRBs – that they are the result of outbursts from young magnetars, or neutron stars with very powerful magnetic fields – is correct.

“Owing to their strong magnetic fields, magnetars are quite unpredictable,” Fong said.

“In this case, the FRBs are thought to come from flares from a young magnetar. Massive stars go through stellar evolution and becomes neutron stars, some of which can be strongly magnetized, leading to flares and magnetic processes on their surfaces, which can emit radio light. Our study fits in with that picture and rules out either very young or very old progenitors for FRBs.”

It also helps strengthen the connection between FRBs and massive, star-forming galaxies. Previous studies were not able to rule out that the blasts were coming from dwarf galaxies that were hidden by a more masssive one – but the new study allowed researchers to rule out such hidden dwarf galaxies.