(ORDO NEWS) — Astronomers at the Massachusetts Institute of Technology and others have detected a strange and persistent radio signal from a distant galaxy that appears to be flashing with surprising regularity.
The signal is classified as a fast radio burst, or BR, an intense burst of radio waves of unknown astrophysical origin that typically lasts no more than a few milliseconds.
However, this new signal persists for up to three seconds, which is about 1000 times longer than the average BR. During this period, the team detected bursts of radio waves that repeat every 0.2 seconds in a distinct, periodic heartbeat-like pattern.
The researchers named the signal BR 20191221A, and it is the longest-running BR with the clearest periodic structure to date.
The source of the signal is in a distant galaxy, several billion light-years from Earth. Exactly what that source might be remains a mystery, although astronomers suspect the signal could come from either a radio pulsar or a magnetar, which are varieties of neutron stars the extremely dense, rapidly spinning, collapsed cores of giant stars.
The team hopes to find more periodic signals from this source, which can then be used as an astrophysical clock. For example, the frequency of bursts and how it changes as the source moves away from Earth can be used to measure the expansion rate of the universe.
Analyzing the structure of radio bursts 20191221A, scientists have found similarities with the radiation of radio pulsars and magnetars in our own galaxy. Radio pulsars are neutron stars that emit beams of radio waves that appear to pulsate as the star rotates, while magnetars produce similar radiation due to their extreme magnetic fields.
The main difference between the new signal and the radio emission from our own galactic pulsars and magnetars is that BR 20191221A appears to be more than a million times brighter.
Astronomers say the bright flashes could come from a distant radio pulsar or magnetar, which normally gets less bright as it spins, but for some unknown reason spewed a whole series of bright flashes into a rare three-second window that CHIME was lucky enough to catch.
Astronomers hope to capture additional bursts from periodic BR 20191221A, which will help clarify understanding of its source and neutron stars in general.
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