Astronomers have spotted a peculiar fast radio burst that is coming from a dead galaxy billions of light-years away, further raising questions on the nature and origins of such powerful cosmic signals. The discovery has been detailed in two studies appearing in The Astrophysical Journal Letters, challenging long-held beliefs about the connection between FRBs and star-forming regions of space.
The signal, FRB 20240209A, originates on the periphery of an old galaxy that stopped forming stars more than 11 billion years ago. Scientists believe the object is around 130,000 light-years away from the center of the galaxy, an area that contains nothing but dead stars at the end stages of their lifecycle.
“This is both surprising and exciting, as FRBs are expected to originate inside galaxies, often in star-forming regions,” said Vishwangi Shah, lead author of one of the studies and an astronomer at McGill University. “The location of this FRB so far outside its host galaxy raises questions as to how such energetic events can occur in regions where no new stars are forming.”
FRBs are extremely brief but incredibly energetic and last only milliseconds. A single FRB can emit more energy in its short duration than the Sun can produce in an entire year. Scientists have long thought that FRBs come from magnetars-neutron stars that have extremely strong magnetic fields. However, the majority of magnetars form from massive stars that undergo supernovae, so there must be active star-forming regions for them to exist.
This theory is contradicted by the host galaxy of FRB 20240209A, which lacks young stars. Researchers are led to search for an alternative explanation. Actually, a previous FRB found in 2022 near Messier 81, another galaxy without active star formation also challenged the existing assumptions. Both signals share one interesting feature: their origins could be within globular clusters, basically tight collections of ancient stars.
To determine whether FRB 20240209A is found in a globular cluster, astronomers intend to use the James Webb Space Telescope to make follow-up observations. According to Wen-fai Fong, coauthor of both papers and astrophysicist at Northwestern University, “This discovery compels us to rethink the origins of FRBs and consider unusual explanations.”
This discovery has further added to the enigma surrounding FRBs, providing a teasing glimpse into mysterious forces that control the cosmos.
