Astronomers have found only the second example of a highly active, repeating Fast Radio Burst (FRB) with a compact source of weaker but persistent radio emission between bursts.
Astronomers have found only the second example of a highly active, repeating Fast Radio Burst (FRB) with a compact source of weaker but persistent radio emission between bursts. The discovery raises new questions about the nature of these mysterious objects and also about their usefulness as tools for studying the nature of intergalactic space. The scientists used the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) and other telescopes to study the object, first discovered in 2019.
The object, called FRB 190520, was found by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in China. A burst from the object occurred on May 20, 2019, and was found in data from that telescope in November of that year. Follow-up observations with FAST showed that, unlike many other FRBs, it emits frequent, repeating bursts of radio waves.
Observations with the VLA in 2020 pinpointed the object’s location, and that allowed visible-light observations with the Subaru telescope in Hawaii to show that it is in the outskirts of a dwarf galaxy nearly 3 billion light-years from Earth. The VLA observations also found that the object constantly emits weaker radio waves between bursts.
“These characteristics make this one look a lot like the very first FRB whose position was determined — also by the VLA — back in 2016,” said Casey Law, of Caltech. That development was a major breakthrough, providing the first information about the environment and distance of an FRB. However, its combination of repeating bursts and persistent radio emission between bursts, coming from a compact region, set the 2016 object, called FRB 121102, apart from all other known FRBs, until now.
Read more at National Radio Astronomy Observatory
Image: Artist's conception of a neutron star with an ultra-strong magnetic field, called a magnetar, emitting radio waves (red). Magnetars are a leading candidate for what generates Fast Radio Bursts. (Credit: Bill Saxton, NRAO/AUI/NSF)