Fast Radio Bursts Come from Within the Milky Way, Astronomers Say

Fast radio bursts aren't exotic chirps of energy as astronomers once believed, rather they come from within the Milky Way, Harvard-Smithsonian Center for Astrophysics astronomers have said.

Fast radio bursts are brief, bright flashes of energy. Only six of these FRBs have been recorded so far.

In July this year, a team of researchers reported detecting these FRBs. At that time, Swinburne University of Technology in Melbourne researcher Matthew Bailes had said that the radio bursts might be coming from magnetic neutron stars, known as 'magnetars.'

Researchers analyzing these FRBs found that these pulses came to Earth after passing through a large column of electrons. Astronomers had hypothesized that if these electrons are spread across the vast intergalactic space, then the pulses must've travelled billions of light years to reach earth. Therefore, these pulses should have come from high-energy events.

Since, gamma-ray bursts don't produce radio frequencies; astronomers looked at other cosmic events such as a neutron star collapsing into a black hole, according to a news release.

Avi Loeb of the Harvard-Smithsonian Center for Astrophysics (CfA) and his colleagues reasoned that the FRBs might be coming from our local universe as electrons in stellar corona could cause the same effect.

Young stars with low mass and contact binaries with mass of the sun can produce these radio bursts. Contact binaries are binary star systems in which two stars orbit so closely that they touch each other or share a gaseous envelope.

Loeb and team tested their theory by looking at the sky using the telescopes at Tel-Aviv University's Wise Observatory, in Israel. They searched the locations of the radio bursts to look for star systems.

The team found contact binary system, which had two "Sun-like stars orbiting each other every 7.8 hours." Researchers used statistics to rule out the idea that the contact binary was in the FRB location by coincidence. These stars are located 2,600 light-years from earth. 

"Whenever we find a new class of sources, we debate whether they are close or far away," said Loeb.

When Gamma-ray bursts were discovered (in the 1960s), astronomers had believed that they were from our own galaxy. Only later did they realize that these GRBs were coming from billions of light years away.

"Here we have exactly the opposite," explained Loeb.

The study was reported in the journal Monthly Notices of the Royal Astronomical Society.