For only the second time ever, scientists have tracked down the location of a fast radio burst emitting regular signals to a galaxy not far from our own.
European astronomers – working with members of the Canadian Hydrogen Intensity Mapping Experiment (CHIME) fast radio burst (FRB) collaboration – have tracked down a mysterious signal first picked up in 2018.
Publishing their findings to Nature, the European VLBI Network (EVN) used eight telescopes spanning locations from the UK to China to simultaneously observe the repeating radio source known as FRB 180916.J0158+65.
What makes these repeating, millisecond-long signals so mysterious is that often they are of unknown origin, but now CHIME has helped researchers locate its origins – just 0.5bn light years from Earth. This makes it around seven times closer than the only other FRB localised so far, and more than 10 times closer than any of the few non-repeating FRBs scientists have managed to pinpoint.
Refining the source position
Using a technique known as Very Long Baseline Interferometry, the researchers achieved a level of resolution high enough to localise the FRB to a region approximately seven light years across. This is equivalent of trying to spot a person on Earth from the moon.
With such precision, the CHIME telescope was trained to look at the FRB’s origin point. This added a new chapter to the mystery surrounding their origin because it is in a very different environment compared with the first ever signal pinpointed, FRB 121102. Additionally, because it is relatively close, it is now possible to look at the FRB further using many other telescopes.
Since beginning operations in 2018, CHIME has detected dozens of FRBs, thereby greatly increasing their rate of discovery.
“By recording and processing the raw signal from each of the antenna elements that make up CHIME, we were able to refine the source position to a level close enough for EVN to successfully observe and localise multiple bursts from this FRB source,” said co-author Daniele Michilli of McGill University and a CHIME/FRB team member.
Looking to the future, another CHIME/FRB team member, Victoria Kaspi, added: “We have a new chance to perhaps detect emissions at other wavelengths – x-ray or visible light, for instance. And if we did, that would be hugely constraining of the models.”