A multinational group of astronomers using the 64-m Parkes Radio Telescope in eastern Australia has observed a fast radio burst happening live.
Artist conception of a magnetar – one of the proposed sources for fast radio bursts. Image credit: NASA.
Over the past few years, astronomers have observed a new phenomenon – a brief burst of radio waves – lasting only a few milliseconds.
It was first seen in 2007, when scientists went through archival data from the Parkes telescope in eastern Australia. Since then they have seen six more such bursts in the telescope’s data and a seventh burst was found in the data from the Arecibo telescope in Puerto Rico.
They were almost all discovered long after they had occurred, but then astronomers began to look specifically for them right as they happen.
Now, a team of astronomers led by Emily Petroff from the Swinburne University of Technology and the Australia Telescope National Facility has succeeded in observing the first live burst.
“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,” said Petroff, who is the first author of a paper published in the Monthly Notices of the Royal Astronomical Society.
The characteristics of the event, labeled FRB 140514, indicated that the source of the burst was up to 5.5 billion light years from Earth.
“It could have given off as much energy in a few milliseconds as the Sun does in a day,” said co-author Dr Daniele Malesani from the University of Copenhagen’s Dark Cosmology Centre.
FRB 140514 left another clue as to its identity, but a puzzling one. The Parkes telescope captured its polarization – something that had not been recorded for previous bursts.
Polarization can be thought of as the direction electromagnetic waves, such as light or radio waves, ‘vibrate’. It can be linear or circular.
The radio emission from FRB 140514 was more than 20 percent circularly polarized – which hints that there are magnetic fields near the source.
“Together, our observations allowed the scientists to rule out some of the previously proposed sources for the bursts, including nearby supernovae,” said co-author Dr Mansi Kasliwal from the Carnegie Institution for Science.
“Short gamma-ray bursts are still a possibility, as are distant magnetic neutron stars called magnetars, but not long gamma ray bursts.”
“Identifying the origin of the fast radio bursts is now only a matter of time. We’ve set the trap. Now we just have to wait for another burst to fall into it,” Petroff said.
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E. Petroff et al. 2015. A real-time fast radio burst: polarization detection and multiwavelength follow-up. MNRAS 447 (1): 246-255; doi: 10.1093/mnras/stu2419
