An international group of astronomers has detected 535 Fast Radio Bursts (FRB), the highest-ever detected in a single sky scanning, possibly emerging from young neutron stars present in the universe.

FRBs are radio pulses that look like light flashes and last for a fraction of a millisecond, and which can glow anytime.

Located at the Dominion Radio Astrophysical Observatory in British Columbia in Canada, scientists used the radio telescope Canadian Hydrogen Intensity Mapping Experiment (CHIME) to carry out its maiden sky scanning after it became operational in 2018.

TIFR–National Centre for Radio Astrophysics (NCRA), McGill University and McGill Space Institute, Dunlap Institute of Astronomy and Astrophysics at the University of Toronto, University of British Columbia and Canada Foundation for Innovation were involved in the sky scanning using CHIME.

A catalogue with all 535 FRBs was released at the American Astronomical Society meeting on Wednesday.

Though FRBs were first detected in 2007 and since then, about 140 bursts have been confirmed, it is the first time that a single sky survey, lasting for 12 months between June 2018 and June 2019 in this bandwidth, has detected such a large number of bursts.

“Within one year of the sky scanning, CHIME was able to detect anywhere between 2 to 8 FRBs every day. No FRBs had been detected, back then, in the 400 to 800 MHz bandwidth. During the year-long scanning, a total of 535 FRBs were detected and identified with their characteristics…18 of these bursts were found to be repeated ones, that is, emerging from the same source,” Shriharsh Tendulkar, TIFR and NCRA faculty involved in this FRB detection and cataloguing, told The Indian Express.

Of the FRBs which were tagged as repeat bursts from the same source, one source was found to emit bursts once after every 16.5 days, he said. “The repeat burst was found to last slightly longer than those which flashed only once,” said Pragya Chawla, CHIME team member and a PhD student at McGill University.

“We were unable to find similar periodicity among the other 17 repeated bursts,” he added.

What makes CHIME an advanced radio telescope is its ability to look at a large area of the sky, even though it is kept stationary.

Despite having the telescope’s eyes looking into large areas of the sky, the challenge, Tendulkar said, was that FRBs emerged from all directions and were well distributed in the sky.

But the advantage CHIME enjoys, as it monitors more than half of the celestial sphere with very high sensitivity, has increased chances for detecting more FRBs, said another McGill PhD scholar, Mohit Bharadwaj.

Such is the data handling capacity of CHIME that it processes 7 terabits of information every second – roughly some percentage of the world’s internet traffic.

“It is then by using the Machine Learning, Artificial Intelligence and specialised algorithms that these interferences – through mobile towers, airlines or satellites — are filtered out to ultimately confirm an FRB among millions of radio signals. The vast volumes of data of the order of 7 terabits per second is compressed to 140GB, after which further processing is done,” explained Tendulkar, who has been associated with CHIME since 2015.

 

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