Scientists still don’t fully understand how quickly radio bursts (FRBs) are generated, but new research is shedding light on the possible origins of these mysterious signals that seem to come from all corners of the cosmos. Published in Naturethe study offers new insights into these elusive radio pulses.
FRBs, short bursts of electromagnetic radiation that can be detected in radio waves, have long puzzled astronomers.
These signals typically have an average frequency of about 1400 MHz and flicker for only a fraction of a second, making them among the most mysterious signals produced by the universe. Sources of FRBs are known to be located millions, even billions, of light-years from Earth.
One prominent theory attributes FRBs to magnetars: neutron stars with the most intense magnetic fields in the universe.
Scientists believe that interactions between a magnetar’s magnetic field and gravitational forces can cause ‘starquakes’, potentially resulting in FRBs. However, not all FRBs behave in the same way, suggesting that other mechanisms may be at play.
By analyzing galaxies in which FRBs have been detected, the study authors identified environmental conditions that appear favorable for their formation.
The research shows that FRBs typically originate in galaxies that are rich in young stars and have exceptionally high masses – a combination that is rarely observed.
Young stars, which are often massive, typically have a short lifespan and eventually explode as supernovae, leaving behind neutron stars, including magnetars. This evidence suggests that star-forming regions with an abundance of young stars can promote the creation of FRB sources.
The study also points to the importance of a galaxy’s metallicity: the abundance of elements heavier than hydrogen and helium. Massive galaxies generally contain higher levels of these elements, which are called “metals” in astronomy.
This high metal content supports the formation of massive stars, which can later become magnetars or other neutron stars that can be linked to FRBs.
Still, scientists note that supernova events in galaxies occur at a rate comparable to that of star formation, and if magnetars from supernovae were the main source of FRBs, we would expect the distribution of FRBs to match that of supernovae.
Since this is not the case, this suggests that supernova-formed magnetars may not be the primary origin of FRBs.
Alternatively, magnetars that can produce FRBs could arise from the merger of binary star systems, a scenario that could occur in galaxies close to massive stars.
Although this study does not definitively indicate the source of FRBs, but supports the magnetar hypothesis and highlights how specific galactic environments may be crucial in generating these bursts.
