20 new deep-space radio signals detected by Outback telescopes
Fast radio bursts (FRBs) are one of the most intriguing celestial mysteries out there at the moment. These incredibly powerful radio signals last mere milliseconds, making it difficult to track what they are and where they're coming from, but a huge radio telescope array spread across the Australian Outback is helping figure it out. Astronomers have now announced the discovery of 20 new FRBs in a bit over a year, including the brightest and closest events yet seen.
The first FRB was spotted in 2007 as an anomaly in old data, but it wasn't until 2015 that the first one was directly witnessed live. Almost 30 of them had been detected by early 2017, when a CSIRO radio telescope in Western Australia began searching for them. And with the team now announcing the first big batch of results, it sounds like that hunt has been a successful one.
"We've found 20 fast radio bursts in a year, almost doubling the number detected worldwide since they were discovered in 2007," says Ryan Shannon, lead author of a study describing the new finds. "Using the new technology of the Australia Square Kilometre Array Pathfinder (ASKAP), we've also proved that fast radio bursts are coming from the other side of the universe rather than from our own galactic neighbourhood."
Among this new batch of events, the team observed the most powerful FRB to date, as well as the nearest, which is estimated to be just 425 million light-years away. That might not sound particularly close, but it's a cosmic stone's throw considering most others are at distances of several billion light-years.
The gone-in-a-flash durations of FRBs make it hard for astronomers to pinpoint exactly where in the sky they're coming from, but there are other ways to figure that out. As the signal travels those billions of light-years, it passes through huge amounts of dust, gas and other matter, which slows down certain wavelengths more than others. Measuring those delays can tell us plenty.
"Timing the arrival of the different wavelengths tells us how much material the burst has traveled through on its journey," says Jean-Pierre Macquart, co-author of the study. "And because we've shown that fast radio bursts come from far away, we can use them to detect all the missing matter located in the space between galaxies – which is a really exciting discovery."
This big batch of data shows how successful ASKAP has been in its first 20-odd months of operation, but this is just the beginning. The P in that acronym stands for Pathfinder, meaning this is just the precursor to a much bigger project known as the Square Kilometre Array (SKA). Set to be built across both Australia and South Africa, this telescope would be able to image much bigger swathes of sky and hopefully catch more FRBs in the act.
The research was published in the journal Nature, and the team describes the work in the video below.