A Bizarre Radio Mark From Deep Space Has Been Noticed Beating Like a Heart
A brand-new radio signal from deep space is once again challenging our understanding of these mysterious phenomena.
Not only is this brand-new fast radio burst, called FRB 20191221A, another extremely rare repeater, but it is not even that quick: the radio flashes received across intergalactic space are three seconds in duration, concerning 1,000 times longer than standard.
However, bursts of higher intensity radiation happen every 0.2 seconds within this three-second window– something never before seen in a rapid radio burst.
The detection was produced by the CHIME detector in December 2019, and scientists instantly recognized they were onto something peculiar.
“It was unusual,” stated astrophysicist Daniele Michilli of the MIT Kavli Institute for Astrophysics and Space Research.
“Not just was it very long, lasting about three seconds, but there were periodic peaks that were incredibly precise, emitting every split second– boom, boom, boom– like a heartbeat. This is the very first time the signal itself is periodic”.
Rapid radio bursts are one of the most fascinating current cosmic mysteries. They are extremely strong bursts of radiation in radio wavelengths that flare from intergalactic space in a very brief space of time– typically milliseconds in duration. Within that quick blink of time, the burst gives off as much energy as 500 million Suns.
The majority of fast radio bursts flare just once as well as have not been heard from since. These are impossible to predict; to perceive one, we simply need to hope that one happens when we have a radio telescope pointed in the best direction (although projects like CHIME, with a large viewing location, are helping immensely in this regard). These are the most common kind of FRB.
More rarely, repeated marks are received from a single point in the sky. These are the repeating rapid radio bursts. Because they repeat, scientists may point a telescope at the sky and study the signals in much greater detail.
It is unclear, nevertheless, if the exact mechanism is responsible for all rapid radio bursts.
They can differ in intensity, wavelength, polarization, and dispersion. One rapid radio burst holds a significant clue: in 2020, for the very first time, a rapid radio burst was detected coming from within the Milky Way. It was traced to a kind of neutron star called a magnetar, suggesting that these extremely magnetized, ultradense things might be responsible for at least some fast radio bursts.
“CHIME has now detected lots of FRBs with different properties,” Michilli said. “We have actually seen some that live inside very turbulent clouds, while others look like they remain in tidy environments. From the properties of this brand-new signal, we may say that around this source, there is a cloud of plasma that has to be extremely turbulent”.
As for what it is, the signs even point to a neutron star of some kind (sorry, still no aliens).
Neutron stars are the collapsed cores of giant stars that have finished their lives and ejected most of their material into space. No longer supported by the outside pressure of fusion, the core collapses into an incredibly dense thing, around 20 kilometres (12 miles) across, but up to an estimated 2.3 times the mass of the Sun.
Magnetars are a sort of neutron star with an insanely powerful magnetic field. Because of the outside pull of this magnetic field competing with the internal pull of gravity, magnetars periodically erupt in large quakes.
Pulsars are neutron stars that eject beams of radio emission from their poles, spinning at velocities down to millisecond scales so that the beam occurs to pulse. Michilli and his mates analyzed the bursts from FRB 20191221A and found features in common with emissions from magnetars and pulsars.
There is simply one problem: although it is unclear how far FRB 20191221A traveled, it has possibly come from another galaxy, and its outburst appears to be over a million times brighter than magnetars and pulsars in our own galaxy.
“There are not many objects in the Universe which emit strictly periodic marks,” Michilli explained. “Examples which we know of in our own galaxy are radio pulsars as well as magnetars, that rotate and produce a beamed emission similar to a lighthouse. Furthermore, we think this new signal could be a magnetar or pulsar on steroids.”
The team wishes that they may catch some more outbursts from the mystery source of FRB 20191221A to reduce both where it comes from and what might be causing it. In turn, this might help us better understand neutron stars.
“This detection raises the question of what can cause this extreme signal that we have never seen before, and how can we utilize this signal to study the Universe,” Michilli stated. “Future telescopes promise to detect thousands of FRBs a month, and then we may find many more of these periodic signals”.
Read the original article on Science Alert.
The research has been published in Nature.
