Similar to gamma-ray bursts (GRBs) and gravitational waves (GWs), fast radio bursts (FRBs) are also among the strongest and most mysterious phenomena in astronomy. According to Science Alert, such events cover bursts that expel more amounts of energy within a millisecond than the sun releases within three days.
Recurring Fast Radio Bursts
Universe Today reports that, though the majority of these bursts take place for just milliseconds, there have been occasions when the FRBs recurred. Though specialists are still unsure about the cause of these repetitions, global collaborative efforts and dedicated observatories have remarkably boosted the event count that can be studied.
One of the leading observatories is the CHIME (Canadian Hydrogen Intensity Mapping Experiment), which is a next-gen radio telescope that is stationed at the DRAO (Dominion Radio Astrophysical Observatory) in British Columbia. Because of its large field of view and vast coverage, the telescope plays an indispensable part in the detection of FRBs.
According to IFL Science, specialists of CHIME have remarkably scaled up the FRB count observed by the telescope. In fact, the CHIME/FRB Collaboration was able to discover 25 new recurring FRBs. This was based on CHIME's data that was detected from 2019 to 2021.
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25 New Repeating FRBs Spotted
Science Alert notes how there are no current models or theories that can fully and conclusively explain the sources and properties of the bursts.
While the CHIME was originally designed to gauge the universe's history of expansion by tracing neutral hydrogen, it has been seen as an ideal tool for looking into FRBs. This is why there is the CHIME/FRB Collaboration, which aims to trace and characterize these radio bursts and find where they come from.
In their recent study, lead author and Dunlap Postdoctoral Fellow Ziggy Pleunis and colleagues relied on a few algorithms for clustering that looked into several events in the sky that have similar dispersion measures (DMs), which refer to the delay of time from high down to low frequencies, which is due to the interactions of the burst with the material as it moves through space.
Pleunis notes how this clustering algorithm takes into account all the FRBs picked up by the CHIME and searches for FRB clusters that have consistent dispersion measures and sky positions within uncertainties of measurements. The researchers then perform different checks to ensure that cluster bursts indeed share the same source.
Among the 1,000 spotted FRBs, only 29 were observed to have a recurring nature. All of these repeating FRBs were also seen to have irregular repetitions. The only exception is FRB 180916 which has a predictable pulse every 16.35 days.
Through the new algorithm, the CHIME/FRB Collaboration was able to pick up 25 new repeating FRB sources. This remarkably increases the available recurring FRBs for study.
The researchers also noted interesting features about these recurring FRBs. Pleunis expresses that when carefully counting FRBs and repeating sources, around 2.6% of all FRBs repeat. For several of the fresh sources, only a few bursts were detected, which means that the sources are relatively inactive to the point where they are close to the ones that had only one observable FRB. Pleunis notes how specialists cannot rule out the possibility that those sources that expelled one burst could exhibit repeated bursts in the future. There is a possibility that all sources repeat bursts but that several of these remain inactive. Explanations regarding FRBs should explain the hyperactivity of some FRBs and the inactivity of others.
Such findings could help future surveys that may benefit from next-gen radio telescopes.
In the meantime, the prodigious rate of new FRB detections (including recurring ones) could imply that radio astronomy is in for a breakthrough.
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