• Repeating Radio Signals Are a Deep Space Mystery and Astronomers Just Found a Second One

    Date:10 January 2019 Author: Brendon Petersen

    In 2007, radio astronomers discovered what they love most: a mystery.

    Two researchers, combing the archives of the Parkes Observatory in Australia, found a radio signal the observatory recorded six years prior, but that nobody had noticed. It was fast—just a matter of milliseconds—but what impressed them was the power behind the signal, emitting 500 times the energy of the sun.

    Since then, astronomers have sought to find out what’s causing these enigmatic bursts. Maybe it’s black hole and neutron star collisions. Maybe something at the centers of galaxies is falling into a supermassive black hole just right. Or maybe it’s dark matter interacting with pulsars, causing an energetic collapse. None of these theories can really be tested yet because there’s been one problem with studying fast radio bursts: Most of them are one and done, detected and then gone in an instant.

    A new set of papers published today in Nature, however, could bring the answer just a little bit closer. For only the second time, researchers have found a fast radio burst source that repeats its signal. The repeater burst comes as part of a series of 13 new fast radio bursts (FRB) found by the Canadian Hydrogen Intensity Mapping Experiment (CHIME) collaborators.

    The new burst, FRB 180814.J0422+73, was discovered in the summer of 2018, before CHIME was fully online. Once CHIME was fully up and running, it heard the source a handful more times, always coming from the same direction of the sky, though astronomers are still trying to pinpoint an exact source. Only one other repeating FRB is known, FRB 121102. It was originally detected in 2012 and confirmed to repeat in 2015.

    Astronomers are still trying to figure out what is causing the phenomena. The duration of the bursts suggests that it’s a small source, while the way the radio bursts “scatter” suggest they’re taking place inside an extreme environment, like a black hole or neutron star. It’s even been suggested that the origin could be dense objects like those colliding.

    To really figure out what the heck is going on, astronomers will need to find additional sources that repeat so they can compare them to each other—and, maybe, to find some other event (like a visible light burst) that ties the radio signal to a specific location in the universe and gives clues to what else is happening in the region.

    For now, all we have is two repeating sources and several dozen outliers—but at least it’s a good start.


    Originally posted on Popular Mechanics

    Latest Issue :

    July/August 2020