SKA precursor telescope ASKAP discovers 20 new fast radio bursts

News
by Cassandra Cavallaro on 11 October 2018
Researchers using the Australian Square Kilometre Array Pathfinder (ASKAP) telescope have nearly doubled the known number of ‘fast radio bursts’ – powerful flashes of radio waves from deep space.
ASKAP
An artist’s impression of fast radio bursts in the sky above the SKA precursor ASKAP. This “fly’s eye” configuration allows the telescope to see much more of the sky at one time. (Credit: OzGrav, Swinburne University of Technology)

The team’s discoveries include the closest and brightest fast radio bursts ever detected. Their findings were reported yesterday in the journal Nature.

Fast radio bursts come from all over the sky and last for just milliseconds. Scientists don’t know what causes them but it must involve incredible energy – equivalent to the amount released by the Sun in 80 years.

ASKAP is operated by CSIRO at the Murchison Radio-astronomy Observatory (MRO), a remote site in outback Western Australia which will also be home to the SKA’s low-frequency telescope.

“We’ve found 20 fast radio bursts in a year, almost doubling the number detected worldwide since they were discovered in 2007,” said lead author Dr Ryan Shannon, from Swinburne University of Technology and the OzGrav ARC Centre of Excellence.

“Using the new technology of 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.”

Co-author Dr Jean-Pierre Macquart, from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR), said bursts travel for billions of years and occasionally pass through clouds of gas.

“Each time this happens, the different wavelengths that make up a burst are slowed by different amounts. Eventually, the burst reaches Earth with its spread of wavelengths arriving at the telescope at slightly different times, like swimmers at a finish line,” he said.

“Timing the arrival of the different wavelengths tells us how much material the burst has travelled through on its journey. 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.”

The boom in the discovery rate is partly down to ASKAP’s extremely wide field of view: at 30 square degrees, it’s 100 times larger than the full Moon.

The antennas can also operate in a “fly’s eye” configuration, with each pointing in a different direction to observe an even wider patch of sky: 240 square degrees all at once.

“This discovery by ASKAP is very impressive,” said SKA Organisation Project Scientist Evan Keane. “Looking forward to the SKA, we don’t really know how many fast radio bursts we’ll find until we have a look, as it’s going into the unknown. But extrapolating up from these rates, using our sensible assumptions, we’re looking at hourly detections.

“Considering we spent a decade trying to find a few dozen of these, it’s a very exciting time for radio astronomers working in this area.”