Scientists Detect More Repeating Radio Signals From Deep Space

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The CHIME Pathfinder telescope is located at the Dominion Radio Astrophysical Observatory in British Columbia, Canada. Andre Recnik [CC BY-SA 4.0]/Wikimedia Commons

Fast radio bursts (FRBs), mysterious high-energy astrophysical phenoma that have defied explanation, have been blamed on everything from aliens to microwave ovens. They are incredibly strong signals that have puzzling mathematical regularity, and scientists believe they are coming from deep space.

But the presence of a new type of FRB may help astronomers understand how they work and where they might be coming from.

A collaborative team of researchers using a telescope in Canada recently detected a special batch of repeating FRBs from space, bringing to 10 the number of this kind of of FRB that have been discovered. Dozens, perhaps hundreds, of regular FRBs have also been found.

These millisecond-long bursts of energy, which were only first discovered in 2007, seem to occur all over the sky. The discovery of repeating FRBs matter because they're easier to track long-term than one-offs, which flare and are never seen again.

The researchers' work was published on Cornell's, an electronic preprint repository, and submitted to Astrophysical Journal.

Their work is based at the Canadian Hydrogen Intensity Mapping Experiment (CHIME) radio telescope in British Columbia, which looks at the sky in a whole new way. It's range is from 400 to 800 megahertz MHz, whereas previously discovered FRBs had radio frequencies around 1,400 MHz.

"CHIME reconstructs the image of the overhead sky by processing the radio signals recorded by thousands of antennas with a large signal-processing system," Kendrick Smith, of the Perimeter Institute for Theoretical Physics in Ontario, told "CHIME's signal-processing system is the largest of any telescope on Earth, allowing it to search huge regions of the sky simultaneously."

Astronomers now believe that FRBs may be more common than previously thought but that our technology hasn't caught up yet to detect all of them.

While CHIME may be leading the way in finding low-frequency FRBs, another radio telescope picked up on a unique FRB a few years ago that shed light on its mysterious origin and helped lay the groundwork for further analysis of matter in our universe.

How a faint glow from a FRB sparks a theory

Parkes Observatory
Parkes Observatory began detecting frequent radio bursts in 1998. CSIRO

While scientists still haven't pinpointed whether or not FRBs all come from the same type of source or are vastly different in origin, scientists in Australia believe they discovered one source back in 2015.

Or at least, they confirmed the source of one of the fast radio bursts: a galaxy roughly 6 billion light-years away in the Canis Major constellation, reported Science News. That's a long way away, proving once and for all that these perplexing radio signals are not coming from within our own galaxy.

The bursts have been difficult to pinpoint, in part because they last only a few milliseconds but also because only several dozen of them have ever been detected. But a burst captured by the Parkes radio telescope in Australia in April 2015, was followed by a faint radio glow that slowly faded over the course of six days. This additional glow offered enough information for scientists to trace the burst back to its origin, a distant elliptical galaxy.

Scientists suspected that the burst might have been generated from a merging pair of neutron stars, though this is just one hypothesis. It's also possible that fast radio bursts come in several different varieties and have different sources. That this particular burst's galaxy of origin has been pinpointed does not mean that the origin of the phenomenon itself has been solved. There's much still to learn about these peculiar signals.

Interestingly, the search for this burst's source might also have solved another riddle of the universe: the so-called "missing matter" problem. There should be much more matter in our universe than scientists have been able to detect so far, at least according to current models of the universe. This fast radio burst showed a lot of "wear and tear," however — and that's evidence that it must have bumped into lots of matter during its journey through the space between galaxies.

This could be the missing matter that scientists have been looking for, invisible ions hidden in the darkness of intergalactic space.

These are all exciting finds, proof that there's a lot of good science that can come from studying these mystifying signals, whether they lead to aliens, merging neutron stars or something else entirely.