In a paper published in Nature, astronomers have reported a fast radio burst (FRB) whose characteristics are different from almost all other FRBs previously detected, except one.
FRBs are bright flashes of light that appear for a few milliseconds and then vanish. Since the first FRB was discovered in 2007, 140 more were discovered until June 2021, according to a post on the MIT website. “Their origins are unknown, and their appearance is unpredictable,” MIT said.
The new study in Nature describes FRB 20190520B, first discovered in 2019. What makes it different is that unlike many other FRBs, it emits frequent, repeating bursts of radio waves. And between bursts, it constantly emits weaker radio waves. “Here we report the detection and localization of the repeating FRB 190520B, which is co-located with a compact, persistent radio source and associated with a dwarf host galaxy of high specific-star-formation…,” the paper said.
Only one FRB has been previously observed to behave this way. Called FRB 121102, that was discovered in 2012.
Calling the behaviour strange, the US National Radio Astronomy Observatory (NRAO) said on its website that 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.
“These characteristics make this one look a lot like the very first FRB whose position was determined — also by the VLA — back in 2016. Now we have two like this, and that brings up some important questions,” NRAO quoted researcher Casey Law of Caltech, ands one of the paper’s authors, as saying.
The astronomers have suggested that there may be two different mechanisms producing FRBs, or that the objects producing them may act differently at different stages. Among the candidates for the sources of FRBs are the superdense neutron stars left over after a supernova, or magnetars (neutron stars with ultra-strong magnetic fields).