Astronomers detect persistent radio signal from far-off galaxy

An international team of astronomers, using the CHIME large radio telescope, have detected a strange and persistent radio signal from a far-off galaxy that appears to flash with surprising regularity.

The new signal, classified as a fast radio burst (FRB), persists for up to three seconds, about 1,000 times longer than the average FRB. The team, comprising astronomers from MIT and universities across Canada and the United States, detected bursts of radio waves that repeat every 0.2 seconds in a clear periodic pattern, similar to a beating heart. The signal, labelled FRB 20191221A, is currently the longest-lasting FRB, with the clearest periodic pattern, detected to date.

According to the researchers, the source of the signal lies in a distant galaxy, several billion light-years from Earth. They suspect the signal could emanate from either a radio pulsar or a magnetar, both of which are types of neutron stars - the dense, collapsed cores of massive stars that exploded as a supernova.

The team hopes to catch additional bursts from the periodic FRB 20191221A, which can help to refine their understanding of its source, and of neutron stars in general.

"This detection raises the question of what could cause this extreme signal that we've never seen before, and how can we use this signal to study the universe. Future telescopes promise to discover thousands of FRBs a month, and at that point we may find many more of these periodic signals," noted Daniele Michilli, a postdoc in MIT's Kavli Institute for Astrophysics and Space Research. Michilli led the discovery first as a researcher at McGill University, and then as a postdoc at MIT.

CHIME, short for Canadian Hydrogen Intensity Mapping Experiment, is an interferometric radio telescope that continuously observes the sky as the Earth rotates, and is designed to pick up radio waves emitted by hydrogen in the very earliest stages of the universe.

The discovery, published in the journal Nature, is authored by members of the CHIME/FRB Collaboration, including MIT co-authors Calvin Leung, Juan Mena-Parra, Kaitlyn Shin, and Kiyoshi Masui at MIT, along with Michilli.