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News – Canadian astronomers discover second mysterious radio explosion



ASTRONOMY

CBC News

Thursday, January 10, 2019, at 4:23 PM – In the depths of space, there are radio signals that astronomers do not understand. Now a Canadian research team has found a repetitive signal, just the second of a kind to be discovered.

Fast radio blasts, or FRBs, are cosmic radio bursts that last only milliseconds. The source is of something with an extremely powerful magnetic field that produces a signal along the radio frequency band.

In a new paper published in the journal Nature, researchers reveal that a newly discovered radio telescope in British Columbia – the Canadian Hydrogen Intensity Mapping Experiment (CHIME) – has captured 13 more FRBs, but more importantly, it has captured a second, repetitive FRB.

The first FRB, designated FRB 121102, was discovered in 2007 using telescope data from 2001. Since then, 36 were found – 19 last year by researchers using an Australian radio telescope.

The CHIME telescope in British Columbia will search our universe for phenomena such as rapid radio explosions, pulsars, and more. (CHIME, Andre Renard, Dunlap Institute for Astronomy and Astrophysics, University of Toronto)

But exactly what is causing those powerful radio signals that are traveling from distant galaxies is not known. Many theories abound – even those involving extraterrestrials – but some of the major theories involve an object that is highly magnetized, such as a star called magnetar.

In 2015, Paul Scholz, a PhD student at McGill University, discovered that a previously detected FRB was repeated. He left the astronomers scratching their heads over an already bizarre cosmic puzzle.

THE MYSTERY DEPENDS

"We certainly hoped the CHIME telescope would be able to discover a lot of fast radio blasts," said Ingrid Stairs, a member of the CHIME team and astrophysicist at the University of British Columbia. "And we were lucky enough to find 13 of those things in the pre-commissioning phase."

The pre-commissioning phase meant that the telescope was not operating at its maximum capacity. In fact, he was only looking at a quarter of the sky he could observe.

This visible light image shows the FRB 121102 fast-host host galaxy (Gemini / AURA / NSF / NRC Observatory)

For Kendrick Smith, a cosmologist at the Perimeter Institute for Theoretical Physics in Waterloo, Ont., Who worked on detection software, FRBs represent a unique challenge.

"FRBs were an unexpected mystery. There are not so many qualitative mysteries in astrophysics," Smith said. "So explaining its nature has become one of the biggest unresolved problems in astrophysics in recent years."

FRBs are similar to pulsars, small, fast, dense stars that emit signals as they spin, like a cosmic beacon. However, these pulsars were found in our galaxy. For FRBs to be detected from other galaxies it means that the signal has to be trillions of times brighter than a pulsar.

"This is one followed by 12 zeros," said Shriharsh Tendulka, a McGill University astronomer and member of the CHIME team. "We have no idea how to do something so brilliant."

Repeating FRBs may be a rare find, but they are even stranger than those of their unique counterparts. In regular FRBs, they emit a single peak. But on both repeaters, astronomers have found different peaks arriving at slightly different frequencies and times.

"We do not see these types of structures from other rapid radio bursts that are in a single explosion," said Tendulkar. "So that's exciting. It can point to a difference between your internal mechanisms."

These 13 FRBs, which include the repeater, were detected at a much lower frequency than had previously been detected. Most of the FRBs found are at frequencies close to 1400 megahertz (MHz). But these were found in the 400 to 800 MHz range.

"The CHIME frequency band is in this gap where we did not know anything, so it's fantastic," said Tendulkar. "That gives us a lot more information."

MORE TO COME

Stairs credits the findings to an "incredible team" of postdoctoral researchers and is confident more discoveries are on the horizon.

"CHIME is looking all over the northern sky every day, so there are many possibilities to find more of these things," she said. "The fact that we have found a second like this, in a way, implies that there may be a lot more out there."

As for the mystery behind the FRBs – and especially the repeated ones – the Canadian team hopes that with CHIME now at full capacity, more of these repeaters will come out.

"CHIME is still in its early days and most of the results are yet to come," Smith said.

Nicole Mortillaro article, originally published in CBC.ca.

SEE BELOW: CLEAREST IMAGES OF THE MOST DISTINCT OBJECT KNOWN IN THE SOLAR SYSTEM

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