15 'could it be aliens?' fast radio bursts observed in one night

Who or what had 10 million trillion trillion joules to play with, 3 billion light years away?

Fast Radio Burst-hunters have suffered London Bus syndrome again: fifteen have shown up at once.

A bout of sky-watching at Green Bank in West Virginia, under the auspices of the Breakthrough Initiative's Listen project, has turned up 15 pulses from repeater source FRB 121102.

Boffins already knew FRB 121102 was enticing: back in January, researchers said it could push out 10 million trillion trillion joules in mere milliseconds, and it was the first FRB to be pinned down to a host galaxy (a dwarf around 3 billion light years away).

The new observations were made by University of California Berkeley postdoc Dr Vishal Gajjar, who used the Breakthrough Listen instrument at Green Bank on August 26 to accumulate 400 terabytes of observations of FRB 121102's location.

The data was collected in just five hours – the reason there's so much is that the instrument covered all frequencies from 4 GHz to 8 GHz.

Dr Gajjar took those observations, looking for short pulses showing the characteristic dispersion (delay as a function of frequency) that indicates gas between Earth and the source.

“The distinctive shape that the dispersion imposes on the initial pulse is an indicator of the amount of material between us and the source, and hence an indicator of the distance to the host galaxy,” the Breakthrough Initiative's announcement explains.

The 15 new pulses happened in just those five hours, showing the source is in a “newly active state”. The several gigahertz of captured bandwidth “should shed additional light on the processes giving rise to FRB emission”.

Breakthrough's announcement has also given rise to the inevitable “is it aliens?” speculation, because that's the question Stephen Hawking and Yuri Milner wanted to answer when they established the Breakthrough Initiative.

“Whether or not FRBs eventually turn out to be signatures of extraterrestrial technology, Breakthrough Listen is helping to push the frontiers of a new and rapidly growing area of our understanding of the Universe around us”, the announcement says.

The group promises a deeper analysis in a future journal article, and has put its observations on The Astronomer's Telegram for all to see. ®


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