Astronomers Discover Source of Radio Wave Bursts

Astronomers Discover Source of Radio Wave Bursts
Comet Neowise is viewed in the early morning sky from Mississippi Mills, Ontario on July 18, 2020. (Sean Kilpatrick/The Canadian Press)
Andrew Chen

Something in space has been releasing fleeting blasts of radio waves, and scientists have finally unraveled this decade-old astronomical mystery.

The outbursts of energy, known as fast radio bursts (FRBs), are millisecond-duration radio pulses which were first identified in 2007 from archived data recorded at the Parkes Observatory in New South Wales, Australia, in July 2001.
But what caused the FRBs have been a puzzle to astrophysicists—until researchers from three teams of international astronomers, including a group of Canadian scientists, concluded on a likely source: magnetars.
“Magnetars are highly magnetized young neutron stars that occasionally produce enormous bursts and fares of X-rays and γ-rays,” said a group of Canadian astronomers.
A neutron star is born from the core of a massive star that collapses after it runs out of fuel. An ordinary neutron star has a magnetic field that is a trillion times that of the Earth’s magnetic field.

But a magnetar’s magnetic field is 1,000 times more powerful than a neutron star.

On April 28, 2020, FRBs from a known magnetar—SGR 1935+2154—were captured by the Canadian Hydrogen Intensity Mapping Experiment (CHIME), a radio telescope in Dominion Radio Astrophysical Observatory in British Columbia.

Following the announcement of the CHIME team, scientists from a NASA-funded project said they also detected the FRBs, using the Survey for Transient Astronomical Radio Emission 2 (STARE2) telescope (pdf).

What is special about this new FRB—coded FRB 200428—is that it came from a mere 30,000 light-years away.

“FRBs ... are generally millions to billions of light-years away from us. But this thing is in our galaxy and much closer to us,” Canadian astrophysicist Paul Scholz told CBC News. “Compared to [other] FRBs, it’s in our backyard, so we can study it in much more detail.”
Chinese astronomers supported this discovery with their own observations (pdf) from the Aperture Spherical Telescope (FAST) in Guizhou.

Magnetars are only one of the many models used in the study of FRB sources. What scientists want to know next is how magnetic energy is released as radio waves.

“All this technology that we have comes out of our understanding of the universe, of physics,” said Scholz. “And through understanding them, we will have a better understanding of how the universe works, how physics works.”