A team of astronomers from the Massachusetts Institute of Technology (MIT), McGill University and other scientific institutions have detected a strange and persistent radio signal coming from a distant galaxy. The signal does indeed appear to flicker, and it does so with a regularity that has surprised scientists.
Classified initially as a FRB (Fast Radio Burst either Fast Radio Burst), the signal, however, does not behave like the rest of the FRBs detected so far. In fact, it can last up to three seconds, about 1,000 times longer than the average FRB. And, in that time, it emits radio bursts that follow a clear periodic pattern and repeat exactly every 0.2 seconds. Nobody, until now, had seen something like this.
Radio signal FRB 20191221A
In an article published in the magazine ‘Nature‘the researchers, all of them members of the CHIME/FRB collaborationhave labeled the strange signal as FRB 20191221A. CHIME (Canadian Hydrogen Intensity Mapping Experiment), is a Canadian radio telescope specially designed to answer the most important questions in astrophysics and cosmology, and on December 21, 2019 it captured a potential FRB, which immediately caught the attention of Daniele Michilli, director of the investigation, that he noticed something unusual while scanning the incoming data.
“Not only was it very long -remembers the scientist- lasting about three seconds, but there were periodic spikes that were remarkably precise, emitting every fraction of a second -bum Bum bum- like the beating of a heart. This is the first time we’ve seen a signal that itself is periodic.”.
“There aren’t many things in the Universe that emit strictly periodic signals. -Add Aaron Pearlman, another of the signatories of the article. Examples that we know of in our own galaxy are radio pulsars and magnetars, which rotate and produce a beam similar to a lighthouse. And we think this new signal could be a magnetar or pulsar on steroids.”.
As explained in the article, the team hopes to detect more periodic signals from the same source, which could then be used as an ‘astrophysical clock’. For example, the frequency of the outbursts and how they change as the source moves away from Earth could be used to measure the rate at which the Universe is expanding.
Similarities to emissions from pulsars and magnetars
By analyzing the pattern of radio bursts from FRB 20191221A, Michilli and colleagues found similarities to emissions from radio pulsars and magnetars in our own galaxy. Radio pulsars are neutron stars that emit beams of radio waves that appear to pulse as the star rotates, while magnetars produce similar emission due to their extreme magnetic fields.
But there is a fundamental difference between the new signal and radio emissions from our own galactic pulsars and magnetars: FRB 20191221A is more than a million times brighter. A powerful ‘train’ of exceptionally bright bursts that the telescope was lucky to catch before the emitting object returned to normal? If so, it is unknown what could be the mechanism that drove this sudden activity.
“CHIME has detected many FRBs with different properties Michilli explains. We have seen some that live inside clouds that are very active, while others seem to be in clean environments. From the properties of this new signal, we can tell that around this source there is a cloud of plasma that must be extremely turbulent.”.
Now, astronomers just have to stay tuned so they don’t miss the next periodic burst from FRB 20191221A. Perhaps in this way they will be able to understand the origin of this intriguing signal, even stranger than conventional FRBs. “This detection Michilli concludes. It raises the question of what could cause this extreme signal that we have never seen before and how we can use it to study the Universe.”.
Font: JOSE MANUEL NIEVES / ABC
Reference article: https://www.abc.es/ciencia/detectan-latido-corazon-radio-miles-millones-anos-20220713184838-nt.html
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