Boffins find Galaxy making killer radiation, rule out Samsung phone as source

Fast gamma rays and fast radio bursts tracked to same source

NASA's exploding star illustration

It's not just radio any more: Penn State University boffins have turned up a “fast gamma ray burst” that correlates with a source of a fast radio burst (FRB).

The still-mysterious FRBs have excited astro-boffins ever since 2013.

In 2015, Australian astronomer Emily Petroff pulled off the first real-time observation of an FRB – a neat trick when the phenomenon is transient – and by March of this year, a Cornell University paper described a repeating FRB.

Now, the same thing's been spotted in the gamma wavelengths – and according to this paper, the gamma output of FRB 131104 (also discovered by Australia's Parkes radio telescope) is a billion times its radio-frequency output.

The radio and gamma ray bursts came from the direction of Carina, a dwarf spheroidal galaxy.

The boffins were supremely lucky: as the Penn release (at Eurekalert) notes, the discovery came about because NASA's Swift satellite was looking at the right bit of sky in November 2013.

Penn professor Derek Fox says “Although theorists had anticipated that FRBs might be accompanied by gamma rays, the gamma-ray emission we see from FRB 131104 is surprisingly long-lasting and bright”.

The gamma-ray outburst lasted up to six minutes, compared to the milliseconds of radio signals that came from FRB131104.

Both the duration and the intensity – “more than a billion times” that of the radio output of the event – indicates an event that would be bad news for anyone nearby.

Possible causes could include flares from magnetars (highly magnetised neutron stars); neutron stars colliding to form a black hole; or perhaps some kind of supernova or black hole accretion event. All of these would ruin your day if you happened to live in the same galaxy.

To choose between them, Fox believes theorists will have to get to work on their maths (which, according to research by the University of Exeter, frightens even physicists): “The problem is that no existing models predict that we would see an FRB in these cases”.

As the abstract of the paper notes, correlated FRB-and-gamma ray sources will provide a handy “candle” for probing the universe. ®


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