Cosmic bursts of a distant past

Print edition : August 23, 2013

CSIRO’s Parkes radio telescope, which was used to confirm a population of fast radio bursts, is shown superimposed on an image showing the distribution of gas in our galaxy. An artist’s impression of a single fast radio burst is shown located well away from the Galactic plane emission. Photo: Swinburne Astronomy Productions

MYSTERIOUS bursts of radio waves originating from billions of light years away have left the scientists who detected them speculating about their origins. The international research team says that their brightness and distance suggest they come from cosmological distances when the universe was just half its current age. The findings were published in the journal Science. The burst energetics indicate that the radio waves originate from an extreme astrophysical event involving relativistic objects such as neutron stars or black holes.

Study lead Dan Thornton of the University of Manchester and Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) says: “The radio bursts last for just a few milliseconds and the furthest one that we detected was 11 billion light years away.”

Astonishingly, the findings also suggest that there should be one of these signals going off every 10 seconds. Max-Planck Institute Director and University of Manchester professor Michael Kramer explained: “The bursts last only a tenth of the blink of an eye. With current telescopes we need to be lucky to look at the right spot at the right time. But if we could view the sky with ‘radio eyes’, there would be flashes going off all over the sky every day.”

The team used the CSIRO Parkes 64-metre radio telescope in Australia to obtain their results. Matthew Bailes, from the Swinburne University of Technology, in Melbourne, thinks the origin of these explosive bursts may be magnetic neutron stars, known as “magnetars”: “Magnetars can give off more energy in a millisecond than our sun does in 300,000 years and are a leading candidate for the burst.”

The researchers say their results will also provide a way of finding out the properties of space between the earth and where the bursts occurred. Ben Stappers, collaborator from Manchester’s School of Physics and Astronomy, says: “We are still not sure about what makes up the space between galaxies, so we will be able to use these radio bursts like probes in order to understand more about some of the missing matter in the universe.”