New Fast Radio Burst Challenges Astronomers’ Longstanding Theories

Astronomer Calvin Leung expressed enthusiasm last summer as he analyzed information from a freshly established radio telescope to accurately determine the source of recurrent bursts of powerful radio emissions — known as fast radio bursts (FRBs) — originating from somewhere in the northern constellation of Ursa Minor.

Leung, a recipient of the Miller Postdoctoral Fellowship at the University of California, Berkeley, aspires to ultimately uncover the origins of these enigmatic bursts and utilize them as tools to map the large-scale architecture of the cosmos, essential for understanding its inception and development. He had crafted much of the programming that enabled him and his team to integrate data from multiple telescopes, allowing them to triangulate the position of a burst with remarkable precision.

The initial thrill transformed into confusion when his partners from the Canadian Hydrogen Intensity Mapping Experiment (CHIME) employed optical telescopes to investigate the area and found the source nestled within the distant periphery of a long-extinct elliptical galaxy, which should, in all likelihood, not harbor the type of star believed to generate these bursts.

Instead of discovering a predicted “magnetar” — a highly magnetized, rotating neutron star left behind from the core collapse of a youthful, massive star — “the question became: How can you account for the presence of a magnetar in this ancient, lifeless galaxy?” Leung remarked.

The youthful stellar remnants theorists suspect produce these millisecond bursts of radio signals ought to have vanished ages ago in the 11.3-billion-year-old galaxy, situated 2 billion light-years from Earth and boasting a mass over 100 billion times that of the sun.

“Not only is this the first FRB discovered outside a lifeless galaxy, but it is also the farthest from the galaxy it is linked to among all other FRBs. The FRB’s location is astonishing and raises questions regarding how such energetic phenomena can transpire in areas where no new stellar formation is taking place,” noted Vishwangi Shah, a doctoral student at McGill University in Montreal, Canada, who refined and built upon Leung’s initial calculations regarding the burst’s location, termed FRB 20240209A.

Shah is the lead author of a research paper concerning the FRB published today (Tuesday, Jan. 21) in the Astrophysical Journal Letters, alongside a second study by peers at Northwestern University in Evanston, Illinois. Leung, a co-author on both publications, is a principal developer of three supplementary telescopes — termed outriggers — to the initial CHIME radio array located near Penticton, British Columbia. He guided Shah at McGill while he was pursuing his doctoral studies at the Massachusetts Institute of Technology (MIT) and later held an Einstein Postdoctoral Fellowship at UC Berkeley before receiving his Miller fellowship.

New CHIME outrigger in California

This week, a third outrigger radio array will become operational at Hat Creek Observatory, a facility in Northern California that was previously owned and run by UC Berkeley and is now operated by the SETI Institute in Mountain View. Collectively, the four arrays will significantly enhance CHIME’s capability to accurately identify FRBs.

“When utilized in conjunction with the three outriggers, we anticipate being able to accurately locate one FRB daily to its originating galaxy, which is significant,” stated Leung. “That’s 20 times enhancement compared to CHIME equipped with two outrigger arrays.”

With this newfound accuracy, optical telescopes can adjust to identify the types of star groups — globular clusters, spiral galaxies — that give rise to the bursts and ideally pinpoint the stellar origin. Of the approximately 5,000 sources detected thus far — with over 95% identified by CHIME — few have been traced back to a specific galaxy, complicating validation efforts to determine if magnetars or other types of stars are the actual source.

As highlighted in the recent paper, Shah averaged multiple bursts from the repeating FRB to enhance the location precision provided by the CHIME array and one outrigger array in British Columbia. After its discovery in February 2024, astronomers logged 21 additional bursts through July 31. Since the paper was submitted, Shion Andrew at MIT integrated data from a second outrigger at the Green Bank Observatory in West Virginia to affirm Shah’s published position with 20 times improved precision.

“This outcome contests prevailing theories that connect FRB origins to events within star-forming galaxies,” commented Shah. “The source might be situated in a globular cluster, a dense area of ancient, inactive stars beyond the galaxy. If verified, it would make FRB 20240209A only the second FRB associated with a globular cluster.”

She did note, however, that the previous FRB originating from a globular cluster was linked to a live galaxy, as opposed to an ancient elliptical galaxy where star formation ceased billions of years ago.

“It’s evident that significant opportunities for discovery remain regarding FRBs, and their environments could be crucial to revealing their mysteries,” stated Tarraneh Eftekhari, who holds an Einstein Postdoctoral Fellowship at Northwestern and is the primary author of the second paper.

“CHIME and its outriggers will enable us to perform astrometry at an unparalleled level compared to the Hubble Space Telescope or the James Webb Space Telescope. It will be their responsibility to investigate further to locate the source,” Leung added. “It truly is an extraordinary radio telescope.”

The research was supported by the Gordon and Betty Moore Foundation, NASA, the Space Telescope Science Institute, the National Science Foundation, the David and Lucile Packard Foundation, the Alfred P. Sloan Foundation, the Research Corporation for Science Advancement, the Canadian Institute for Advanced Research, the Natural Sciences and Engineering Council of Canada, the Canada Foundation for Innovation, and the Trottier Space Institute at McGill.

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