Eight new fast repeated radio bursts detected

Using the telescope of the Canadian Hydrogen Absorption Mapping Experiment (CHIME), astronomers have identified eight new, repeated sources of fast radio gusts (FRB). The discovery, reported in an August 9 article on arXiv.org, could shed new light on the origins and nature of these mysterious phenomena.

FRBs are intense peaks of radio emissions lasting several milliseconds and exhibit the characteristic scattering of radio pulsars. The physical nature of these bursts is still unknown and astronomers examine various explanations, ranging from the emission of a synchrotron emitter by young magnetars in supernova remnants to cosmic string cusps.

The first FRB was discovered in 2007. Known as Lorimer Burst, it was a singular event such as a supernova. Five years later, the first repeated FRB was detected. Named FRB 121102, the source has a complex burst morphology, bursting frequency drifts, as well as a complex phenomenology of pulses.

Although dozens of FRBs have been identified so far, only two of them repeat their signals. These repeaters could be the key to solving the mysteries of the FRB, as astronomers anticipating future waves can prepare extensive follow-up observation campaigns aimed at investigating in detail about these lightning bolts.

Now, a team of astronomers led by Bridget C. Andersen of McGill University in Montreal, Canada, reports the detection of eight new FRB repeaters, which could be a breakthrough in studies of these explosive events.

"We report the discovery of eight recurring FRB sources discovered using the telescope of the Canadian Hydrogen Absorption Mapping Experiment (CHIME)," astronomers wrote.

The newly identified FRBs have dispersion measurements ranging from 103.5 to 1,281 parsecs / cm³. For the two FRBs with a small extent of dispersion, astronomers can not exclude the possibility that they are galactic halo objects. Therefore, follow-up observations on several wavelengths for these sources are proposed to limit their location.

The study revealed that one of the eight new FRBs has a rotation measurement of -115 rad / m²– much lower than that observed for FRB 121102. This allowed astronomers to draw initial conclusions on the general properties of the FRB.

"This, and the lack of a persistent radio source of comparable brightness in the uncertainty regions of Sources 1 and 2, suggests that not all repeaters share the environmental properties of FRB 121102 ", reads the document.

In addition, the researchers found that the repetitive ORLs reported in the study typically included dispersion measures typical of non-recurrent ORRs up to here identified by the chime. However, they show evidence of larger gust widths than non-repetitive bursts. According to the authors of the document, this could suggest different emission mechanisms in repeated and non-repeated sources.

Astronomers have also discovered complex morphologies and sub-gusts drifting downward in some of the eight new FRBs, which could indicate that such phenomenology is not necessarily observed in repeated sources.

In their concluding remarks, the scientists stressed the importance of their discovery, pointing out that this was an important step forward in the current FRB hunt. They added that the new sources offer a great opportunity for follow-up studies, which could unravel the mysterious nature of AROs.

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