Fast Radio Bursts, or FRBs, are short-lived but extraordinarily bright pulses of radio waves coming from mysterious sources outside the Milky Way.
They were first discovered in 2007 but little is known about them particularly because they only last for a few seconds. Their fleeting action makes them difficult to catch and makes it harder for astronomers to pinpoint their exact source.
Radio Signal From Aliens
Researchers have detected only 18 of these phenomena so far. Because much are still unknown about FRBs, there are widespread speculations about their source. Some think they involve a cataclysmic event such as a supernova or a neutron star that collapses into a black hole.
Others think that these are alien radio signals sent by aliens to communicate with us. In 2015, for instance, researchers reported that a strange mathematical pattern that was spotted in fast radio bursts from deep space could be proof of alien civilization. For one particular burst, however, extraterrestrial life could now be ruled out.
Astronomers have finally identified the source of this one radio signal known as FRB 121102, the only known FRB to repeat. This means that multiple radio bursts have been detected coming from the same region in the sky making it easier for scientists to catch this particular FRB again.
Radio Signal Coming From Dwarf And Faint Galaxy
Using a network of 27 radio telescopes in New Mexico called the Karl G. Jansky Very Large Array (VLA) and other telescopes, researchers were able to get high resolution images of the multiple bursts and after 83 hours of observation over a period of six months, they were finally able to track the source of the radio signal: a dwarf galaxy located more than 3 billion light-years away from Earth.
"Our precise localization reveals that FRB 121102 originates within 100 milliarcseconds of a faint 180-microJansky persistent radio source with a continuum spectrum that is consistent with non-thermal emission, and a faint (twenty-fifth magnitude) optical counterpart," study researcher Shami Chatterjee, from Cornell University in Ithaca, New York, and colleagues wrote in their study, which was published in the journal Nature on Jan. 5.
Neutron Stars In Dwarf Galaxy Could Be Source Of Mysterious Radio Waves
Knowing that FRB 121102 came from a dwarf and faint galaxy surprised scientists, but the information also offered clues about the source of these particular radio bursts.
Scientists expect finding most FRBs in large galaxies because they have the largest number of stars and neutron stars. Neutron stars are dense objects that form when a star explodes and the remaining material collapses on itself.
Although the dwarf galaxy has fewer stars, it is forming stars at a high rate suggesting that FRBs are associated with young neutron stars.
"This persistent radio source could be an active galactic nucleus (AGN) at the centre of a galaxy that's feeding (consuming matter from its surroundings), sending out jets, and these sizzles we see are little bits of plasma being vaporised in the jets," Chatterjee said.
Although scientists still do not know what causes these deep space signals, locating the source of the radio signal can bring researchers closer to understanding them better and where they exactly come from.