Canadian and US astronomers are heralding the detection of radio pulses from deep space that they say could be used as something of an astrophysical clock. “The frequency of the explosions, and how they change as the source moves away from Earth, could be used to measure the rate at which the universe is expanding,” explained Daniele Michilli, a postdoctoral researcher at the Massachusetts Institute of Technology (MIT). at the Kavli Institute for Astrophysics and Space Research. The astronomers are working with the Canadian Hydrogen Intensity Mapping Experiment (CHIME), which operates an interferometric radio telescope consisting of four large parabolic reflectors. It is located at BC’s Dominion Radio Astrophysical Observatory near Penticton. What the researchers spotted is a signal classified as a fast radio burst (FRB) — an intensely powerful burst of radio waves of unknown astrophysical origin that typically lasts for a few milliseconds at most. In December 2019, CHIME received a signal of a possible FRB, which immediately caught the attention of Michilli, who was scanning the incoming data. “It was unusual,” Michilli said. “Not only was it very long, about three seconds long, but there were periodic spikes that were extremely precise, sending out every split second — boom, boom, boom — like a heartbeat. This is the first time that the brand itself is a magazine.” These three seconds are about 1,000 times longer than the average FRB. Within this window, the team detected bursts of radio waves that repeat every 0.2 seconds. The source of the signal is in a distant galaxy, several billion light years from Earth. However, exactly what this source might be remains a mystery. Astronomers suspect it could come from either a radio pulsar or a magnetar, both types of neutron stars — extremely dense, rapidly spinning collapsed cores of giant stars. “There aren’t many things in the universe that emit strictly periodic signals,” Michilli said. “Examples we know in our own galaxy are radio pulsars and magnetars, which rotate and produce a beacon-like beam emission. And we think this new signal could be a magnetar or pulsar on steroids.” While the information was published in the journal Nature on July 13, an FRB catalog was presented by UBC and other researchers on June 9 at a meeting of the American Astronomical Society. “This catalog marks an important turning point in the FRB field,” said Bradley Meyers, a UBC postdoctoral researcher in the Department of Physics and Astronomy and member of the CHIME collaboration. “We are now firmly in the regime where robust analyzes can be used to investigate the properties of FRBs as a population rather than on an individual basis. There’s a huge amount of science we can do with this catalog, and I think a lot of it will be exploring ideas that we haven’t even come up with yet.”
Okanagan Telescope
The CHIME radio telescope was designed and built by scientists at UBC, McGill University, the University of Toronto, the Perimeter Institute for Theoretical Physics and the National Research Council of Canada. Unlike traditional telescopes, CHIME has no moving parts. Instead, it uses more than 1,000 antennas to capture information from all the radio waves that hit its surface. It receives radio signals every day from half the sky as the Earth rotates. “Digital signal processing is what makes CHIME capable of reconstructing and ‘looking’ in thousands of directions simultaneously,” says Kiyoshi Masui, assistant professor of physics at MIT. “This is what helps us detect FRBs a thousand times more often than a traditional telescope.” [email protected] twitter.com/jhainswo
