Mysterious fast radio burst tracked down to nearby galaxy
(From UBC Science) Astronomers in Europe, working with Canada’s CHIME Fast Radio Burst collaboration, have pinpointed the location of a repeating fast radio burst (FRB) first detected by the CHIME telescope in British Columbia in 2018. It's only the second time scientists have determined the precise location of a repeating source of these millisecond bursts of radio waves from space.
In results published in Nature, the European researchers used eight telescopes spanning locations from the United Kingdom to China to simultaneously observe the repeating radio source known as FRB 180916.J0158+65. They were able to achieved a level of resolution high enough to localize the FRB to a region approximately seven light years across – comparable to an individual on Earth being able to distinguish a person on the Moon. With that level of precision, the team was able to train an optical telescope onto the location to learn more about the environment from which the burst emanated. What they found has added a new chapter to the mystery surrounding the origins of FRBs.
"We used the eight-metre 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," said co-author Shriharsh Tendulkar, a former McGill University postdoctoral researcher who co-led the optical imaging and spectroscopic analyses of the FRB's location.
It's is a very different environment for a repeating FRB, compared to the dwarf galaxy in which the first was discovered, and among the closest yet seen.
"There are still a lot of open questions about the sources of fast radio bursts, and knowing what kind of galaxy a particular repeating FRB comes from can help us narrow down the answers," said Deborah Good, a PhD student in physics and astronomy at UBC who is part of CHIME's FRB team. "It's really exciting to be able to make these discoveries from CHIME/FRB, and then to work with other scientists around the world to learn as much as we can about the source of fast radio bursts."
Since it began operation in the summer of 2018, CHIME has detected dozens of fast radio bursts, greatly accelerating the rate of discovery of these transient astrophysical phenomena. With over 1,000 antennas, CHIME’s large field of view gives it a much greater chance of picking up fleeting bursts than conventional radio telescopes that are able to observe only a small area of the sky at a time.
"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," said co-author Daniele Michilli, a McGill University postdoctoral researcher and CHIME/FRB team member.
At half-a-billion light years from Earth, the source of FRB 180916 is around seven times closer than the only other repeating burst to have been localized, and more than 10 times closer than any of the few non-repeating FRBs scientists have managed to pinpoint. That’s exciting for astronomers because it will enable more detailed study that may help narrow down the 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, a leading member of the CHIME/FRB collaboration. "And if we did, that would be hugely constraining of the models."
The CHIME Fast Radio Burst Collaboration
CHIME/FRB is a collaboration of over 50 scientists led by the University of British Columbia, McGill University, the University of Toronto, the Perimeter Institute for Theoretical Physics, and the National Research Council of Canada (NRC). The $16-million investment for CHIME was provided by the Canada Foundation for Innovation and the governments of British Columbia, Ontario and Quebec, with additional funding from the Dunlap Institute for Astronomy and Astrophysics, the Natural Sciences and Engineering Research Council and the Canadian Institute for Advanced Research. The telescope is located in the mountains of British Columbia’s Okanagan Valley at the NRC’s Dominion Radio Astrophysical Observatory near Penticton. CHIME is an official Square Kilometre Array (SKA) pathfinder facility.