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 that product from a distance galaxy. The signal does appear to flicker, and it does so with a regularity that surprised scientists.
Originally classified as a FRB (Fast radio burst oh 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, during 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 that.
Radio signal FRB 20191221A
In an article published in the magazine ‘Nature‘the researchers, all members of the CHIME/FRB collaborationlabeled 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 survey , that he noticed something unusual while scanning incoming data.
“Not only was it very long -recalls 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 see a signal that itself is periodic.”.
“There aren’t many things in the Universe that emit strictly periodic signals. -To add Aaron Pearlman, another of the article’s signers. Examples we know of in our own galaxy are radio pulsars and magnetars, which spin and produce a beam similar to a lighthouse. And we think this new signal could be a magnetar or a pulsar on steroids.”.
As explained in the paper, 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 explosions 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 with emissions from pulsars and magnetars
Analyzing the radio burst pattern of FRB 20191221A, Michilli and his 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 seem to pulsate as the star rotates, while magnetars produce a similar emission due to their extreme magnetic fields.
But there is a fundamental difference between the new signal and the radio emissions from our own galactic pulsars and magnetars: FRB 20191221A is more than a million times brighter. A powerful “train” of unusually bright shards that the telescope was lucky enough to catch before the emitting object returned to normal? If so, it’s unclear what mechanism could be behind this sudden activity.
“CHIME has detected many FRBs with different properties explains Michilli-. We have seen some living inside very active clouds, while others appear to be in clean environments. From the properties of this new signal, we can say that around this source is a cloud of plasma which must be extremely turbulent.”.
Now astronomers just have to stay tuned so they don’t miss the next periodic burst of FRB 20191221A. Perhaps they will be able to understand the origin of this intriguing signal, even stranger than conventional FRBs. “This detection Michilli concludes. This raises the question of what could be causing this extreme signal that we have never seen before and how we can use it to study the Universe.”.
Source: JOSE MANUEL NIEVES / ABC
Reference article: https://www.abc.es/ciencia/detectan-latido-corazon-radio-miles-millones-anos-20220713184838-nt.html