Astronomers identify black hole at galaxy’s centre as source of radio bursts afterglow

Radio telescopes used by the CSIRO in Australia and the Japan National Astronomical Observatory in Hawaii helped find the location of fast radio bursts (FRB). New data discovered the source of the FRBs.

Harvard-Smithsonian Center for Astrophysics astronomers Peter William and Edo Berger say the afterglow from the FRBs originated from the core of a distant galaxy and not associated with FRBs. Since the radio emissions from the source goes up and down but never goes away, they point out it cannot be associated with FRBs.

Berger says the emission originates from an active galactic nucleus powered by a supermassive black hole. The black hole blasts dual jets outward and the complex physical processes within the jets create a constant source of radio waves.

Since the FRB was documented, the astronomer used the radio telescopes of the Very Large Array (VLA) group to have a better look at the galaxy, estimated to be 6 billion light years away, where the signal came. Using the VLA’s radio telescopes, which have strong sensitivity, permitted the astronomers to monitor the radio bursts at the necessary pace without the need to disrupt the pace of the observatory’s regular schedule of operations.

But they were surprised that the signal was still going strong, ruling out FRBs, reports Gizmodo. They noticed the radio bursts were cyclical, becoming stronger and then dimming again. The strength of the persistent radio source varied randomly by a factor of three, William notes, which often reached levels that matched the initial brightness of the afterglow.

He explains the variations they see from Earth to scintillation, a process where interstellar gases make an intrinsically steady radio beacon seem to flicker similar to how the Earth’s atmosphere makes lights from stars twinkle. Williams admits that insofar as the science of FRBs is concerned, astronomers are where they were with gamma-ray burst three decades ago in that they observe it appearing and disappearing but now what these were or caused it.

“Now we have firm evidence for the origins of both short and long gamma-ray bursts. With more data and more luck, I expect that we’ll eventually solve the mystery of fast radio bursts too,” says Williams.