Astronomers have detected a radio signal from the Milky Way. The signal obtained is called a fast radio burst, which lasts for milliseconds and comes from deep in space.
The signal was traced back to a Milky Way magnetar (SGR 1935+2154), a type of neutron star with an extremely strong magnetic field. The magnetar suddenly lit up, sending out a gargantuan millisecond-long burst of bright radio waves, picked up by astronomers on April 28.
It is not the first time that satellites have received radio signals from space. The first FRBs were identified over a decade ago. Theories of their sources include cataclysmic events, particularly when two neutron stars collide or a black hole collapses.
However, these assumptions were rejected when another FRB was detected. Scientists say a black hole can only collapse once, suggesting that the source could be something else.
“Something like this has never been seen before,” Caltech astronomer Shrinivas Kulkarni told ScienceAlert.
Fast radio bursts are one of the most fascinating mysteries in the cosmos. In recent years, an international group of scientists has come together to solve the mystery of FRBs. The collaboration led to the discovery of more FRBs, with researchers using the results to familiarize themselves with more of their locations across the universe.
For example, earlier this year, a group of experts traced an FRB back to a strange V-shaped star-forming region in a vast spiral galaxy half a billion light-years away.
Explanations range from supernovae to extraterrestrials (which, sorry, is extremely unlikely). But one possibility that has caught steam is that FRBs are produced by magnetars.
These neutron stars are already thought to produce starquakes and giant magnetar flares. The recently detected signal was so strong that some radio telescopes could not quantify it.
The STARE2 survey, a project started by Caltech graduate student Christopher Bochenek, is designed exactly for the detection of local FRBs. It received the signal loud and clear, with a fluence of over a million jansky milliseconds. Typically, we receive extragalactic FRBs a few tens of milliseconds jansky.
“If the same signal came from a nearby galaxy, like one of the nearby typical FRB galaxies, it would look like an FRB to us”, Christopher told. The detection was reported on The Astronomer’s Telegram.
It’s even more exciting that the star in question is 30,000 light-years away, which could be considered ‘nearby’ in terms of space.
So far, other researchers studying FRBs have welcomed the findings. Jason W. T. Hessels, a Senior Scientist at ASTRON, Netherlands Institute for Radio Astronomy, described the discovery as a “breakthrough’ for the field.
“We now have direct evidence that a known Galactic magnetar has produced a radio burst that is getting close to as bright as some known extragalactic FRB sources,” he said in an email. “It’s basically guaranteed that some FRB sources must be, by analogy, bursting magnetars, but a key question remains: are they all bursting magnetars, or do FRBs come from a variety of different origins?”