A gigantic but fleeting burst of radio waves has been caught in the act for the first time, helping to narrow down the vast array of things that might cause them. Figuring out what these fast radio bursts – sometimes called blitzars – are or where they come from could help answer some of the biggest cosmological questions.

Cosmic radio bursts – what astronomers call fast radio bursts – are bright flashes of radio waves, lasting only a few milliseconds. The first one was seen retroactively in 2007, only 3 degrees from the direction in space to the Small Magellanic Cloud. Before now, no fast radio burst was observed in real time. Even now, the source of the bursts is unknown.

This week, an international team of astronomers reports a breakthrough. They say that – for the first time – they have observed a fast radio burst as it happened.

John Mulchaey, acting director of the Carnegie Observatories, said: “These events are one of the biggest mysteries in the Universe. Until now, astronomers were not able to catch one of these events in the act.”

Emily Petroff, from the Swinburne University of Technology, added: “These bursts were generally discovered weeks or months or even more than a decade after they happened! We’re the first to catch one in real time.”

The scientists mobilised 12 telescopes around the world and in space to capture the burst. After working out the burst location with the Parkes telescope, the others were used to make follow up observations on different wavelengths.

The burst they saw – exploding 5.5 billion years from Earth. Astrophysicists at the University of Copenhagen did just that and found two sources of X-rays at that position. Those were observed from another telescope and found to be quasars – a type of pulsating black hole – which were “nothing to do with radio wave bursts, but just happen to be located in the same direction” said astrophysicist Giorgos Leloudas, Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen.

“We found out what it wasn’t,” said Daniele Malesani, astrophysicist at the Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen.

“The burst could have hurled out as much energy in a few milliseconds as the Sun does in an entire day. But the fact that we did not see light in other wavelengths eliminates a number of astronomical phenomena that are associated with violent events such as gamma-ray bursts from exploding stars and supernovae, which were otherwise candidates for the burst.”

“The theories are now that the radio wave burst might be linked to a very compact type of object – such as neutron stars or black holes and the bursts could be connected to collisions or ‘star quakes’. Now we know more about what we should be looking for.”

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Journal reference: https://goo.gl/cZQueh.