Fast radio bursts, or bright millisecond-long flashes of radio waves in space, have been one of the most puzzling mysteries facing astronomers. These fast, intense events were first discovered in 2007, and since then, hundreds of them have been detected from distant points across the universe. In a millisecond, the energy generated by these bursts can be as much as what the Sun creates in a year or more, as previous research has indicated. However, what exactly causes these fast radio bursts remains a mystery.
Adding to the mystery is a peculiar pattern observed in a repeating fast radio burst known as FRB 20220912A. A study published in the journal Monthly Notices of the Royal Astronomical Society details the discovery, introducing new enigmas while also providing valuable clues to researchers trying to identify the source of the phenomenon.
Using the Allen Telescope Array (ATA), astronomers detected 35 fast radio bursts coming from the same source over a period of two months. Many FRBs emit radio waves that last for just a few milliseconds before disappearing, but some radio bursts repeat and emit follow-up bursts that have allowed astronomers to trace the signals to distant galaxies.
The peculiar discovery in FRB 20220912A was a notable drop in the center frequency of the bursts, similar to a celestial whistle. The researchers converted the signals into sounds using the notes of a xylophone, with the high notes corresponding to the beginning of the bursts and the low notes acting as final tones.
The researchers attempted to determine a pattern in the times between each burst, but were unable to detect any in the case of FRB 20220912A, showcasing the unpredictable nature of these celestial phenomena.
Lead author of the study, Dr. Sofia Sheikh, said, “This work is exciting because it confirms known properties of FRBs and uncovers new ones.” According to the researchers, each observation of fast radio bursts provides more information and raises more questions.
Researchers suspect that fast radio bursts may come from magnetars, which are the strongly magnetized cores of dead stars. However, other research has suggested that collisions between dense neutron stars or dead stars called white dwarfs could be the cause. “We are narrowing down the origin of FRBs to extreme objects like magnetars, but no existing model can explain all the properties observed so far,” said Sheikh.
The study was the first to observe fast radio bursts using the Allen Telescope Array, which has been undergoing renovations in recent years. Ongoing upgrades will allow astronomers to follow the behavior of fast radio bursts at different frequencies and search for weaker signals.
“This work demonstrates that new telescopes with unique capabilities, like ATA, can provide a new perspective on the remaining mysteries in FRB science,” Sheikh added.