A lot of us would be skeptical if we were told there are objects in the galaxy that give out more powerful energy than the sun – millions of times over. In actual fact, there exist such powerful bursts of energy in our universe, and they’re called Fast Radio Bursts. They are incredibly bright flashes of energy, lasting no more than a second, giving out more than 100 million times more power than the sun.
Scientists first discovered fast radio bursts in 2007. Since then, astronomers have observed with rapt interest these energies make their way throughout the universe. However, their origin was unknown. Scientists couldn’t make out what object produced such an extreme flash of radio waves.
That search for the holy grail of astrophysical mystery seems to be over, as scientists, for the first time, can tell precisely where FRBs are coming from. Through the collaborative efforts of astronomers from world-leading institutions, FRBs were detected in our galaxy for the first time. And now, we can trace precisely the source of these radio pulses.
Astronomers from MIT, McGill University, the University of British Columbia, the University of Toronto, the Perimeter Institute for Theoretical Physics can conclude that FRBs come from a magnetar – a type of neutron star with a very powerful magnetic field.
Kiyoshi Masui, an assistant professor of physics at MIT and lead author of the study, said this is the first time scientists can authoritatively pinpoint the origin of fast radio bursts to a single astrophysical object, using direct observational proofs, MIT scientists report.
Their study, which was published in the journal Nature was led by McGill University, featuring collaborations from over 50 researchers from top universities in the US and Europe. It is interesting to note that all authors on the study belong to the Canadian Hydrogen Intensity Mapping Experiment (CHIME).
This latest discovery was made using the CHIME radio telescope stationed at the Dominion Radio Astrophysical Observatory in British Columbia. CHIME is a piece of complex equipment made of four large reflectors. These reflectors beam their searchlight on incoming radio waves over a thousand antennas. The antennas continuously monitor the sky for incoming radio waves.
This constant tracking was an ongoing project until April 2020, when these astronomers got lucky. There was a burst of activity in the X-ray band of the spectrum from a magnetar in our Milky Way. The magnetar could be found towards the galaxy’s center and 30,000 light-years away from Earth. This magnetar was quite ordinary and just like everyone else found in our galaxy. It was quickly labeled SGR 1935+2154, signifying its coordinates in the sky.
This magnetar was put in the spotlight, with astronomer gearing up for what it had to offer. Their expectations were not dashed when soon after, CHIME picked up a magnetar burst in the X-ray band, which pointed to a fast radio burst. After drawing up coordinates to locate the FRB source, astronomers pinpointed its source to SGR 1935+2154.
When astronomers calculated the magnetar’s brightness, it was 3,000 times brighter than any other magnetar radio signal yet observed in our galaxy.
The next question for scientists to consider was how this magnetar produced fast radio bursts. A lot of theories have been put forward, although none is conclusively acceptable. One of these theories proposes that magnetars generate radio waves by randomly interacting with a magnetic field, similar to how radio waves are generated on Earth.
Radio waves are often produced through synchrotron radiation, whereby a gas of randomly moving high-energy electrons interact with a magnetic field, thereby emitting energy at radio frequencies.
Since this discovery of the fast radio burst-producing magnetar, there have been reports by other scientists of subsequent radio bursts by this same magnetar, although not in the same initial intensity.
The Five Hundred Meter Aperture Spherical Telescope (FAST) in China, which is thought to be extremely sensitive, detected multiple X-ray bursts from the magnetar. However, it did not spot the FRB itself.