Eight new repeating fast radio bursts detected

Eight new repeating fast radio bursts detected
Detection positions of the new CHIME/FRB repeating FRB sources. Credit: Andersen et al., 2019.

Using the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope, astronomers have identified eight new repeating fast radio burst (FRB) sources. The finding, reported in a paper published August 9 on arXiv.org, could shed new light on the origin and nature of these mysterious phenomena.

FRBs are intense bursts of radio emission lasting milliseconds and showcasing characteristic dispersion sweep of radio pulsars. The physical nature of these bursts is yet unknown, and astronomers consider a variety of explanations ranging from synchrotron maser emission from young magnetars in supernova remnants to cosmic string cusps.

The first FRB was discovered in 2007. Known as the Lorimer Burst, the bursts was a singular event such as a supernova. Five years later, the first repeating FRB was detected. Named FRB 121102, the source exhibits complex burst morphology, sub-burst downward frequency drifts, and also complex pulse phenomenology.

Although dozens of FRBs have been identified to date, only two of them were found to repeat their signals. These repeaters could be the key to resolving the mysteries of FRBs as astronomers anticipating the upcoming bursts can prepare extensive follow-up observational campaigns aimed at investigating such flashes in detail.

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 mean a breakthrough in studies of these flaring events.

"We report on the discovery of eight repeating FRB sources found using the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope," the astronomers wrote in the paper.

The newly identified FRBs have dispersion measures ranging from 103.5 to 1,281 parsecs/cm3. For the two FRBs with low dispersion measure, the astronomers cannot exclude the possibility that they are galactic halo objects. Hence, multi-wavelength follow-up observations for these sources are proposed in order to put constraints on their location.

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

"This, and the absence of a comparably luminous persistent radio source in Sources 1 and 2 uncertainty regions, suggest not all repeaters share the environmental properties of FRB 121102," the paper reads.

Moreover, the researchers found that the repeating FRBs reported in the study generally have dispersion measures typical for the non-repeating FRBs so far identified with CHIME. However, they do show evidence of having larger burst widths than non-repeating bursts. This, according to the authors of the paper, could suggest different emission mechanisms in repeating and non-repeating sources.

The astronomers also found complex morphologies and downward-drifting sub-bursts in some of the eight new FRBs, what could indicate that such phenomenology is not necessarily observed in repeating sources.

In concluding remarks, the scientists underlined the significance of their discovery, noting that it represents an important progress in the ongoing hunt for FRBs. They added that the new sources present a great opportunity for follow-up studies, what could disentangle the mysterious nature of FRBs.

Explore further

Canada's CHIME telescope detects second repeating fast radio burst

More information: B. C. Andersen et al. CHIME/FRB Detection of Eight New Repeating Fast Radio Burst Sources,arXiv:1908.03507v2 [astro-ph.HE]: arxiv.org/abs/1908.03507.

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Citation: Eight new repeating fast radio bursts detected (2019, August 19) retrieved 19 October 2019 from https://phys.org/news/2019-08-fast-radio.html
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Aug 19, 2019
How come the SETI people never found these radio bursts? What are they looking for, if not a signal that varies?

Aug 19, 2019
Not that kind of radio signal.

Aug 19, 2019
I dunno, quoting from the paper:

Until now, all such observations have been carried out at radio frequencies above 1 GHz, with bursts detected as high as 8 GHz (Michilli et al.2018; Gajjar et al. 2018), but recently a burst from this source has been reported in the CHIME 400–800-MHz band (Josephy et al. 2019).

From SETI's "Billion-channel Extraterrestrial Assay" regarding the digital signal processing capabilities, "...This allowed BETA to receive 250 million simultaneous channels with a resolution of 0.5 hertz per channel. It scanned through the microwave spectrum from 1.400 to 1.720 gigahertz in eight hops, with two seconds of observation per hop."

Gamma-ray bursts are even candidates (although they're mostly blocked by the atmosphere) but, "John A. Ball from the MIT Haystack Observatory suggests that an advanced civilization that has reached a technological singularity would be capable of transmitting a two-millisecond pulse encoding 1×10^18 bits of information"

Aug 19, 2019
These repeating FRBs are directed signals/messages and are occurring all over the Universe. It is a natural and normal occurrence (in the presence of Mass/Energy) that has been known and understood by many others, but only "now" have humans come to detect them with advanced instrumentation. Some ancient 'cultures' have gone insane after realising the process and the reason for it.

Aug 19, 2019
Intense bursts of radio emission lasting milliseconds

Showcasing characteristic dispersion sweep of radio pulsars
This the question - is this milli-second pulse coming from a rotating star

Because it appears to be from a rotating star which puts doubt on neutron stars

Aug 19, 2019
My guess is that SETI was filtering noise and the noise filters eliminated the FRBs. It's just a guess, though, I have no supporting data.

Aug 20, 2019
My guess is that we could be looking down the barrel of black hole jets and picking up the radio frequencies of those particles from feeding black holes no evidence to prove this.

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