Unveiling the Mystery: Fast Radio Burst Linked to Ancient Star Graveyards

Astronomers are rethinking the source of fast radio bursts (FRBs), those mysterious bursts of radio waves from space. A recent FRB detected in 2024 has been traced back to a large, ancient galaxy located 2 billion light-years away.

Traditionally, scientists believed that FRBs were caused by the deaths of young, massive stars, typically in galaxies where new stars are born. However, the galaxy hosting this new FRB lacks those young stars, suggesting that FRBs might be produced by a variety of events.

“Just when we think we understand these phenomena, the universe surprises us,” said Wen-fai Fong from Northwestern University. “This is what keeps our work exciting.”

The research began when the Canadian Hydrogen Intensity Mapping Experiment (CHIME) detected a new FRB in February 2024, now known as FRB 20240209A. Unlike many FRBs, which are single events lasting just milliseconds, this one has sent out 21 pulses over several months.

The team used an additional telescope, about 37 miles away, to help pinpoint its source. By following up with observations using powerful observatories like W.M. Keck and Gemini, they discovered that this FRB came from the outskirts of a truly massive galaxy, around 11.3 billion years old.

The galaxy, with a mass of around 100 billion suns, may well be the heaviest known host of an FRB to date. Interestingly, FRB 20240209A is located about 130,000 light-years from the center of its galaxy, which is unusual because most FRBs come from regions where new stars are forming.

“This discovery challenges our understanding,” said Vishwangi Shah, who helped pinpoint the FRB’s origin. “FRBs are generally expected to be found in star-filled regions, but this one is far from such areas.” Only one other case of an FRB located at the outer edge of a galaxy has been recorded.

Previously, FRB 20200120E was identified in a dense globular cluster within the nearby Messier 81 galaxy. While different in origin, both FRBs highlight the need to revise our models for how these bursts are generated. It appears these radio bursts can come from old environments, suggesting there might be a subset of FRBs associated with older stars.

“This opens up new possibilities,” Fong mentioned. “Old stellar environments could contribute to these energetic events we see in the universe.”

Currently, about 100 FRBs have been linked to galactic hosts, and many of these are thought to originate from magnetars—highly magnetic neutron stars formed from the remnants of massive stars after they explode. However, in the case of FRB 20240209A, there are no signs of such young stellar deaths, pointing towards older systems instead.

The researchers suspect this FRB might also come from a globular cluster, similar to FRB 20200120E. If confirmed, that would be significant, as it would be only the second FRB known from a globular cluster. They have even proposed using the James Webb Space Telescope for more detailed observations.

“There’s still so much to uncover about FRBs and their environments,” Eftekhari added. “This could be the key to understanding their origins.” The team’s findings are detailed in two recent publications in The Astrophysical Journal Letters.