In February 2024, scientists on Earth detected a powerful radio burst in outer space. To find out where it came from, they traced the flash of energy to an extraterrestrial source and discovered something unexpected.
Scientists led by Northwestern University and McGill University have tracked a fast radio burst (FRB) to the edge of an ancient elliptical galaxy. Scientists previously thought that these fast bursts of radio waves, which generate more energy in a single flare than our Sun produces in a year, were produced only in young galaxies that were steadily forming new stars. However, recent research has detailed two points. sisters research Published on January 21st astrophysics journal letters, Astronomers must reconsider the potential diversity of FRB sources.
The February 2024 FRB, called FRB 20240209A, is not a one-off. Between February and July 2024, the same source occurred 21 times.
“The general theory is that FRBs come from magnetars formed by nuclear collapse supernovae,” said Tarraneh Eftekhari of Northwestern University, who participated in both studies. name. Magnetars are neutron stars with very powerful magnetic fields, while neutron stars are extremely small, dense objects that are thought to form in the aftermath of the explosive death, or supernova, of some large star.
“That doesn’t seem to be the case here,” Eftekhari continued. “Young, massive stars end their lives as core-collapse supernovae, but there is no evidence of young stars in this galaxy. This new discovery reveals that not all FRBs come from young stars. “Maybe there is a subset of Feds involved with older systems.”
The old galaxy in question is 11.3 billion years old and lies 2 billion light-years away from us. Using computer simulations, Eftekhari and her colleagues discovered that the galaxy is extremely bright and 100 billion times larger than our Sun.
“This appears to be the most massive FRB host galaxy to date,” Eftekhari said. “It’s one of the most massive galaxies.” Unusual FRBs not only originate from older galaxies, but also from the edges of galaxies, specifically 130,000 light-years from the center.
“Of the FRB population, this FRB [farthest] said Vishwangi Shah of McGill, who participated in both studies. “This is both surprising and exciting because FRBs are often expected to originate inside galaxies, in star-forming regions. “The location of this FRB is so far outside its host galaxy that it raises the question of how such an energetic event could occur in a region where new stars do not form.”
But FRB 20240209A is not the first FRB to be discovered far from an active star-forming region. This is the second time. In 2022, astronomers tracked the M81 FRB, located 12 million light-years from Earth, to a cluster of stars at the edge of the Messier 81 galaxy.
FRB 20240209A “Could be a twin of the M81 event. [M81 FRB]. This galaxy is far from its home galaxy (far from where stars form), and its star population is very old. They had their heyday and are now entering the retirement phase,” said Wen-fai Fong of Northwestern University, who participated in both studies. “At the same time, these types of older environments are forcing us to rethink the standard FRB ancestral model and turn to more exotic formation channels, which is exciting.”
One of the studies suggests that, like the M81 FRB, the new FRB may also originate from star clusters called globular clusters.
“The globular cluster origin of these recurring FRBs is the most likely scenario to explain why these FRBs are located outside their host galaxies,” Shah explained. “We have no factual knowledge of whether globular clusters exist at the FRB location and we have submitted a proposal to use the James Webb Space Telescope for follow-up observations of the FRB location. If so, this FRB would be the second FRB known to be in a globular cluster. “If not, we will have to consider alternative exotic scenarios for the origin of the Federal Reserve.”
In other words, go back to the drawing board!
