Hunting for pulsars with the Large Phased Array (LPA) radio telescope, Russian scientists have identified a luminous signal at a frequency of 111 MHz, which seems to represent a fast radio burst (FRB) event. This discovery was detailed in a study published on October 17 via the arXiv pre-print platform.

Fast radio bursts are powerful emissions of radio waves that endure only milliseconds, marked by the distinctive dispersion sweeps typical of radio pulsars. The underlying cause of these bursts remains a mystery, with proposed explanations ranging from synchrotron maser radiation produced by youthful magnetars in supernova remnants to the behavior of cosmic string cusps.

Typically, FRBs are singular flashes with durations spanning from 0.08 to 26 milliseconds, and their dispersion measures generally fall between 109 and 2,600 pc/cm³. Among the observational tools capable of identifying such phenomena is the LPA, renowned as one of the most sensitive radio telescopes operating in the meter-wavelength range.

Recently, a group of astronomers spearheaded by Sergey Tyul'bashev of the Pushchino Radio Astronomy Observatory in Russia detected a compelling signal that might qualify as an FRB. The finding emerged during the Pushchino Multibeams Pulsar Search (PUMPS) initiative, while evaluating the observational fidelity of LPA data gathered by the Lebedev Physical Institute (LPI).

This particular pulse, persisting for 211 milliseconds, exhibited a dispersion measure around 134.4 pc/cm³ and peaked at a flux density of approximately 20 Jy. The significant dispersion measure suggests its origin lies beyond our galaxy, corresponding to an estimated luminosity distance of roughly 2.3 billion light-years.

The study notes that this pulse, identified as FRB 20190203, is among the most energetic fast radio bursts recorded to date. However, the researchers have not detected any recurring signals from FRB 20190203 nor observed any corresponding gamma-ray activity.

If the extragalactic origin of FRB 20190203 is confirmed, it would mark the first such detection from the PUMPS survey and the second FRB identified at the relatively low frequency of 111 MHz. Furthermore, it is the first non-repeating FRB discovered at this frequency.

To explain the origin of FRB 20190203, the researchers suggest the synchrotron maser emission model.

"In our view, the characteristics of FRB 20190203 are most consistent with a synchrotron maser source energized by a magnetar," the scientists conclude.