Repeating fast radio burst tracked to its galactic source

Jan. 6 (UPI) -- For only the second time, scientists have tracked a fast radio burst to its source. This time, researchers traced the signal to a nearby spiral galaxy.

The repeating fast radio burst, or FRB, was first detected by the CHIME telescope in British Columbia in 2018.

The CHIME telescope, or the Canadian Hydrogen Intensity Mapping Experiment, was designed to study a variety of radio wave phenomena in the cosmos, including pulsars. Astronomers have also come to rely on CHIME for detecting fast radio bursts.

In the wake of the discovery of FRB 180916, astronomers trained a network of eight telescopes in Europe and Asia, called the European VLBI Network, or EVN, on the FRB's location.

"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 localize multiple bursts from this FRB source," Daniele Michilli, a McGill University postdoctoral researcher and CHIME astronomer, said in a news release.

Using an observational technique known as very long baseline interferometry, or VLBI, researchers successfully pinpointed the region from which the FRB's originated. Scientists trained an optical telescope on the location to identify the cosmic phenomena responsible for the signal.

"We used the eight-meter Gemini North telescope in Hawaii to take sensitive images that showed the faint spiral arms of a Milky-Way-like galaxy and showed that the FRB source was in a star-forming region in one of those arms," Shriharsh Tendulkar, a former McGill University postdoctoral researcher who helped lead the tracking efforts, said in a news release. "This is a very different environment for a repeating FRB, compared to the dwarf galaxy in which the first repeating FRB 121102 was discovered to reside."

Because the FRB signal was one of the cleanest signals yet observed by CHIME, scientists suspected it was coming from a source located on the outskirts of the Milky Way. But while the FRB turned out not to be homegrown, it was still close enough to be studied in detail by ground-based telescopes.

Scientists described their tracking and observational efforts this week in the journal Nature Astronomy. In followup studies, astrnomers hope to locate other types of waves and high-energe phenomena that could be associated with FRB 180916 and help scientists whittle down the list of possible explanations for FRBs.

"We have a new chance to perhaps detect emissions at other wavelengths -- x-ray or visible light, for instance," said McGill University astrophysicist Victoria Kaspi. "And if we did, that would be hugely constraining of the models."