Friday, 18 January, 2019

Astronomers detect more mystery radio bursts from beyond the Milky Way

A second mysterious repeating fast radio burst has been detected in space	 	 	 			Getty Images A second mysterious repeating fast radio burst has been detected in space Getty Images
Theresa Hayes | 10 January, 2019, 09:58

While a bunch of FRBs have been detected previously, this is only the second time one's been observed to repeat itself.

The latest signals to be detected reached Earth from a galaxy 1.5 billion light years away.

The findings were announced by Deborah Good, an astronomer at the University of British Columbia in Vancouver, at a meeting of the American Astronomical Society in Washington on Wednesday. It was originally created to delve into the mystery surrounding dark matter by mapping the distribution of interstellar hydrogen, but it also turns out to be well-suited to take on the mystery surrounding fast radio bursts.

In one of the two papers published in Nature researchers said seeing two repeating blasts probably means there exists a "substantial population" and it's very possible humans will find it.

"And with more repeaters and more sources available for study, we may be able to understand these cosmic puzzles - where they're from and what causes them".

Thirteen flashes were seen via a new radio telescope dubbed the Canadian Hydrogen Intensity Mapping Experiment, affectionately known as Chime. Scientists are still debating whether repeating FRBs come from the same source as the one-time flashes, or instead represent a distinct type of event. The existence of a second repeating burst suggests there could be many more of the mysterious signals in the cosmos.

Most scientists believe they are generated by powerful astrophysical phenomena such as black holes or super-dense neutron stars.

It is not yet clear whether the breeding grounds of repeating bursts are different from those that produce only a single radio pulse.

Constructed in British Columbia, CHIME is composed of 4, 100-meter long half-pipe cylinders of metal mesh which reconstruct images of the sky by processing the radio signals recorded by more than a thousand antennas.

More likely, CHIME's Shiryash Tendulkar says, is the possibility that they come from a "very strongly magnetized, rapidly spinning neutron star called a millisecond magnetar".

The first repeated burst was discovered by the Arecibo radio telescope in Puerto Rico in 2015. While most other FRBs detected were recorded at between 1400 megahertz (MHz) and 2000 MHz, these bursts were found at 400-800 MHz, far lower than ever before.

The repeater detected by CHIME bears a strong resemblance to FRB 121102, said Dunlap Institute astrophysicist Cherry Ng, lead author of the second Nature paper.

The CHIME team, which designed and built the telescope, includes 14 scientists from the University of B.C. alongside others from McGill University, the University of Toronto, the Perimeter Institute for Theoretical Physics and the National Research Council of Canada.

"Whatever the source of these radio waves is, it's interesting to see how wide a range of frequencies it can produce".

Significantly, the 2012 and 2018 "repeaters" have strikingly similar properties. FRBs are typically in the 1,400 MHz range, and the previous lowest radio frequency was at 700 MHz.