A telescope in Canada has found a source of mysterious fast radio bursts that repeat every 16 days, according to a new paper. It’s the first regularly repeating fast radio burst known to science.
Fast radio bursts (FRB) are bright radio blips that originate from deep space. After the initial fast radio burst discovery in 2001, astronomers have found more of these events, at first sporadically and now more frequently with the help of the Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst (CHIME/FRB) Project. Though scientists have previously found repeating FRBs, the newly reported object, called FRB 180916.J0158+65, is the first known to burst at regular intervals.
Last year, CHIME/FRB reported finding eight new sources of FRBs, including this repeating one, which is located in a relatively nearby spiral galaxy. From September 2018 to November 2019, the experiment detected 28 bursts from FRB 180916.J0158+65, according to the paper recently published on the arXiv physics preprint server.
Based on the statistical tests, run by the international collaboration of scientists led by Canadian Institute for Theoretical Astrophysics graduate student Dongzi Li, FRB 180916.J0158+65 emitted its fast blip every 16 days or so. They had enough data to more or less rule out that the periodicity was due to coincidence. The European Very-long-baseline-interferometry Network (EVN) of telescopes corroborated the source by spotting a burst from this FRB on June 19, 2019.
CHIME is a radio telescope in southern British Columbia consisting of four half-cylinders laid side by side, acting as fixed antennae to map the sky. CHIME is designed to map the emission from hydrogen, the universe’s most abundant element, thanks to its wide field of view and the broad range of electromagnetic radiation frequencies it can capture. But the instrument is also adept at hunting for FRBs, as scans 1,024 points in the sky at 16,000 different frequencies, 1,000 times per second, according to the CHIME website.
The mere presence of periodicity in this FRB might give clues into what object could be producing it, according to the paper. Perhaps whatever is producing the radio bursts forms a binary with another celestial body, though the current data doesn’t reveal the identity of the FRB or the companion. Perhaps the object is a rotating magnetar, a kind of compact, magnetized neutron star—though the researchers point out that magnetars typically have rotation periods of less than 12 seconds, far shorter than the 16 days recorded here.
Researchers with knowledge of the paper declined to speak with Gizmodo, since the peer-reviewed version of the paper is currently under embargo by a major scientific journal.
The paper concludes that future observations will need to be carried out at all possible frequencies in order to distinguish between various hypotheses as to what this FRB could be.
We’ve been covering FRBs with much excitement due to their truly “alien” nature, though they’re probably not signals from an intelligent extraterrestrial society. While scientists have detected repeating FRBs before, more observations of periodically repeating FRB might add some clarity—or more frustrating confusion—to the story.