What could be responsible for emitting these bizarre and repeated radio signals?
Astronomers at McGill University have detected short repeating bursts of radio waves from a mysterious source that is located well beyond the edge of our own Milky Way galaxy. Their finding indicates that these bursts of radio waves must have been emitted by a very powerful source that is capable of producing multiple bursts within a minute. Fast radio bursts (FRBs) are nothing new to astronomers, as FRBs have been detected numerous times in the past, but normally they occur as once-off events.
Paul Scholz, a PhD student at McGill University, was filtering through old results during 2015 from previous observations performed at the Arecibo Radio telescope in Puerto Rico, which is currently the world’s largest radio telescope, when he made a surprising discovery.
The Arecibo Observatory in Puerto Rico, the world's largest radio telescope. Credit: NAIC - Arecibo Observatory.
Some of the data he had gather was run through a supercomputer at the McGill High Performance Computing Centre, where it was discovered that earlier FRBs, detected in 2012, exhibited similar properties to the FRBs detected in 2015.
That the signal had repeated itself was surprising and “very exciting,” Paul Scholz stated in a media release. “I knew immediately that the discovery would be extremely important in the study of FRBs.”
Scientist have long been puzzled by FRBs, which were first reported nearly a decade ago, but with the new findings from McGill, it’s clear that FRBs would have at least an alternative origin to those that occur as one-off events.
Astronomers currently speculate that the FRB pulses come from a distant galaxy, based on measurements of an effect known as plasma dispersion. Astronomers can distinguish pulses traveling through space from man-made interference by the influence of interstellar electrons on the pulses omitted. Interstellar electrons cause radio waves to move slower through space and therefore the waves are detected at lower radio frequencies. Since the latest discovery of repeated FRBs has three times more than the maximum dispersion that astronomers would expect from a radio wave originating our Milky Way, it must be coming from somewhere beyond.
With our current understanding, the most likely cause of repeated FRBs could be due to an extragalactic neutron star, Although, in a study published last week, a different research team suggested that FRBs are generated by a cataclysmic event such as short Gamma ray bursts and cannot generate repeated bursts of radio waves. This discrepancy between the studies could be resolved if we discover that there are multiple sources of FRBs.
The findings were published yesterday (March 2) in the journal of Nature.