11.10.2018
An artist's impression of the Australian SKA Pathfinder (ASKAP) radio telescope observing Fast Radio Bursts.
Astronomers are getting new insights into the nature of mysterious phenomena known as Fast Radio Bursts (FRBs), thanks to discoveries made by researchers using a powerful radio telescope called the Australia Square Kilometre Array Pathfinder (ASKAP).
FRBs are intense bursts of radio emissions emanating from beyond the Milky Way, only a few milliseconds in duration. Since the first one was reported in 2007, only 34 have been found.
Now, however, a team headed by Ryan Shannon from Swinburne University of Technology in Australia, reveals in the journal Nature that in the past year it has picked up 20 new ones, almost doubling the total.
The finds confirm that the origin of FRBs is indeed a very long way away.
“Using the new technology of the Australia Square Kilometre Array Pathfinder, we’ve also proved that fast radio bursts are coming from the other side of the universe rather than from our own galactic neighbourhood,” he says.
At present, what causes FRBs is a matter of speculation, but researchers known that the short-lived pulses are immensely powerful, with each one containing energy equivalent to the total emitted by the sun over 80 years.
Co-author Jean-Pierre Macquart, from the International Centre for Radio Astronomy Research (ICRAR), based in Western Australia, says that the bursts travel for billions of years.
Occasionally they pass through clouds of gas, which alters their composition in a way that allows astronomers to deduce important information about their journey.
“Each time this happens, the different wavelengths that make up a burst are slowed by different amounts,” explains Macquart.
“Eventually, the burst reaches Earth with its spread of wavelengths arriving at the telescope at slightly different times, like swimmers at a finish line. 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 new FRB bonanza was made possible by the innovative engineering and operation of ASKAP, which was completed in 2012. The facility is comprises 36 antennas, all working in unison as a single radio telescope.
“The telescope has a whopping field of view of 30 square degrees, 100 times larger than the full Moon,” says Kieth Bannister of Australia’s principal science research organisation, the CSIRO.
“And, by using the telescope’s dish antennas in a radical way, with each pointing at a different part of the sky, we observed 240 square degrees all at once — about a thousand times the area of the full moon.”