Astronomers detected a consistent radio signal from a far-off galaxy that appears to flash with surprising regularity. Called FRB 20191221A, this quick radio burst, or FRB, is presently the longest-lasting FRB, with the clearest periodic pattern, discovered to date. Pictured is the big radio telescope CHIME that selected up the FRB. The signal has been categorized as a fast radio burst, or FRB– an extremely strong burst of radio waves of unidentified astrophysical origin, that usually lasts for a few milliseconds at a lot of. The huge bulk of FRBs observed to date are one-offs– ultrabright bursts of radio waves that last for a few milliseconds before blinking off.
Named FRB 20191221A, this quick radio burst, or FRB, is presently the longest-lasting FRB, with the clearest routine pattern, discovered to date. Imagined is the big radio telescope CHIME that selected up the FRB.
A remote neutron star could be the origin of the clear and periodic pattern of quick radio bursts.
A relentless and unusual radio signal from a far-off galaxy that appears to be flashing with unexpected consistency has been found by astronomers at MIT and in other places.
The signal has been classified as a quick radio burst, or FRB– an extremely strong burst of radio waves of unidentified astrophysical origin, that typically lasts for a couple of milliseconds at many. This new signal is quite special in that it continues for up to 3 seconds, about 1,000 times longer than the average FRB. Within this window, the group of researchers detected bursts of radio waves that duplicate every 0.2 seconds in a clear periodic pattern, similar to a whipping heart.
Labeled by astronomers as FRB 20191221A, the signal is currently the longest-lasting FRB, with the clearest periodic pattern, ever discovered to date.
The source of the signal depends on a distant galaxy situated several billion light-years from Earth. Exactly what that source may be remains a mystery, though astrophysicists believe the signal might originate from either a radio pulsar or a magnetar, both of which are kinds of neutron stars– exceptionally thick, quickly spinning collapsed cores of giant stars.
” There are few things in deep space that discharge strictly regular signals,” states Daniele Michilli, a postdoc in MITs Kavli Institute for Astrophysics and Space Research. “Examples that we understand of in our own galaxy are radio pulsars and magnetars, which rotate and produce a beamed emission similar to a lighthouse. And we believe this new signal might be a magnetar or pulsar on steroids.”
The group of researchers hopes to identify more regular signals from this source, which could then be utilized as an astrophysical clock. They could use the frequency of the bursts, and how they change as the source moves away from Earth, to measure the rate at which the universe is broadening.
The discovery is reported today (July 13, 2022) in the journal Nature, and is authored by members of the CHIME/FRB Collaboration, including MIT co-authors Calvin Leung, Juan Mena-Parra, Kaitlyn Shin, and Kiyoshi Masui at MIT, along with Michilli, who led the discovery first as a scientist at McGill University, and after that as a postdoc at MIT.
” Boom, boom, boom”
Given that the first FRB was found in 2007, numerous similar radio flashes have been discovered across the universe, most just recently by the Canadian Hydrogen Intensity Mapping Experiment, or CHIME, an interferometric radio telescope including 4 large parabolic reflectors that lies at the Dominion Radio Astrophysical Observatory in British Columbia, Canada.
CHIME constantly observes the sky as the Earth turns, and is created to get radio waves discharged by hydrogen in the really earliest stages of deep space. The telescope likewise occurs to be conscious quick radio bursts, and given that it started observing the sky in 2018, CHIME has actually discovered hundreds of FRBs emanating from different parts of the sky.
The vast majority of FRBs observed to date are one-offs– ultrabright bursts of radio waves that last for a few milliseconds prior to blinking off. Just recently, scientists discovered the very first regular FRB that appeared to discharge a routine pattern of radio waves. This signal consisted of a four-day window of random bursts that then repeated every 16 days. This 16-day cycle indicated a routine pattern of activity, though the signal of the real radio bursts was random rather than regular..
On December 21, 2019, CHIME chose up a signal of a potential FRB, which right away drew the attention of Michilli, who was scanning the incoming data.
” It was unusual,” he recalls. “Not only was it long, lasting about 3 seconds, however there were routine peaks that were extremely exact, giving off every split second– boom, boom, boom– like a heart beat. This is the very first time the signal itself is regular.”.
Fantastic bursts.
In examining the pattern of FRB 20191221As radio bursts, Michilli and his colleagues discovered resemblances with emissions from radio pulsars and magnetars in our own galaxy. Radio pulsars are neutron stars that emit beams of radio waves, appearing to pulse as the star rotates, while a comparable emission is produced by magnetars due to their severe magnetic fields.
The main distinction in between the brand-new signal and radio emissions from our own stellar pulsars and magnetars is that FRB 20191221A seems more than a million times brighter. Michilli says the luminescent flashes may originate from a remote radio pulsar or magnetar that is typically less intense as it rotates and for some unknown factor ejected a train of brilliant bursts, in a rare three-second window that CHIME was thankfully positioned to catch.
” CHIME has now discovered many FRBs with different properties,” Michilli states. “Weve seen some that live inside clouds that are really rough, while others appear like theyre in clean environments. From the homes of this new signal, we can say that around this source, theres a cloud of plasma that need to be very unstable.”.
The astronomers intend to catch extra bursts from the routine FRB 20191221A, which can assist to improve their understanding of its source, and of neutron stars in general.
” This detection raises the concern of what might trigger this extreme signal that weve never seen prior to, and how can we utilize this signal to study the universe,” Michilli states. “Future telescopes assure to discover thousands of FRBs a month, and at that point we might find much more of these periodic signals.”.
Reference: “Sub-second periodicity in a quick radio burst” 13 July 2022, Nature.DOI: 10.1038/ s41586-022-04841-8.
This research study was supported, in part, by the Canada Foundation for Innovation.