The source of the signal is in a galaxy billions of light-years from Earth (Getty)
Discover Scholars Astronomy at the Massachusetts Institute of Technology, and other astronomical research centers, a strange, persistent radio signal from a distant galaxy appears to flash with surprising regularity. The signal is classified as a fast radio burst (FRB), a very strong burst of radio waves of unknown astrophysical origin, typically lasting for a few milliseconds at most.
However, this new signal lasts for up to three seconds, about a thousand times longer than the average FRB, and is among the longest-lived signals so far. Within this window, the team detected bursts of radio waves that repeat every 0.2 seconds with a distinct periodic pattern, similar to a heartbeat, according to their findings. the study published July 13 in the journal Nature.
Since the discovery of the first fast radio burst in 2007, hundreds of similar radio flashes have been observed across the universe, most recently by the Canadian Hydrogen Intensity Mapping Experiment, or CHIME, and the last by a radio telescope that measures interferometry, consisting of four large parabolic reflectors. CHIME constantly monitors the sky as the Earth rotates, and is designed to capture radio waves emitted by hydrogen in the very early stages of the universe’s life. The telescope also happens to be sensitive to fast radio bursts, and since it began observing the sky in 2018, it has discovered telescope Hundreds of fast radio bursts emanating from different parts of the sky.
The vast majority of fast radio bursts observed so far are one-time, that is, ultra-bright bursts of radio waves that last for a few milliseconds before they flash.
Researchers have finally discovered the first periodic fast radio burst that appears to emit a regular pattern of radio waves, so it’s not a forever-disappearing flash. This signal consists of four continuous four-day random bursts, then repeated every 16 days. This 16-day cycle indicated a cyclical pattern of activity, although the actual radio burst signal was random rather than cyclical.
The researchers named the observed signal in the study FRB 20191221A, and it is currently the longest-lived FRB, with the clearest periodic pattern discovered to date, because these bursts usually disappear and are not regular.
The source of the signal is in a distant galaxy, several billion light-years from Earth. What exactly could this source be? This remains a mystery though astronomers suspect that the signal could be emitted by a radio pulsar or magnetar, both types of neutron stars with very dense and rapidly rotating cores than giant stars.
Lead author of the study Danielle Michele, a postdoctoral researcher at MIT’s Kavli Institute for Astrophysics and Space Research, explains that such periodic signals come from only a limited number of astronomical phenomena. Examples we know of in our galaxy are radio and magnetic pulsars that rotate and emit a beacon-like beam.
In a statement to Al-Araby Al-Jadeed, Michele says that he believes that this new signal could be a magnetic star or a pulsar. The author hopes to discover more periodic signals from this source, which can then be used as an astrophysical clock. The frequency of the pulses and how they change as the source moves away from Earth can be used to measure the expansion rate of the universe.
In analyzing the pattern of detected radio bursts, Michele and colleagues found similarities with emissions from radio and magnetic pulsars in our galaxy. Radio pulsars are neutron stars that emit beams of radio waves and appear to pulsate as the star rotates, while magnetars produce similar emission due to their intense magnetic fields. “The main difference between the new signal and radio emissions from pulsars and magnetospheres in the galaxy is that the detected explosion appears to be a million times brighter,” according to the author.