(ORDO NEWS) — A team studying radio waves in the universe has discovered something unusual that emits a giant burst of energy three times an hour, unlike anything astronomers have seen before.
The team that discovered it thinks it could be a neutron star or a white dwarf – the collapsed cores of stars – with a super-powerful magnetic field. As it orbits in space, the strange object sends out a beam of radiation that crosses Earth‘s line of sight, and for one minute out of every 20 is one of the brightest radio sources in the sky.
Astrophysicist Dr. Natasha Hurley-Walker of the Curtin University Center’s International Center for Radio Astronomy Research led the team that made the discovery.
“This object appeared and disappeared for several hours during our observations,” she said. “It was completely unexpected. Astronomers were even creepy, because there is nothing like it in the sky. And it is really very close to us – at a distance of about 4,000 light years. It is in our galactic backyard.”
The object was discovered by Curtin University honors student Tyrone O’Doherty using the Murchison Widefield Array (MWA) telescope in the outback of Western Australia and a new technique he developed.
“It’s very interesting that the source that I identified last year turned out to be such an unusual object,” said Mr. O’Doherty, who is now studying for a Ph.D. at Curtin. “The wide field of view and extreme sensitivity of the MWA are ideal for surveying the entire sky and detecting unexpected objects.”
Objects that turn on and off in the universe are not new to astronomers – they call them transients. ICRAR-Curtin astrophysicist and study co-author Dr. Gemma Anderson says: “When you study transients, you’re looking at the death of a massive star or the activity of the remnants it leaves behind.”
Slow transients such as supernovae can appear within a few days and disappear after a few months. Fast transients, such as a type of neutron star called a pulsar, flash on and off within milliseconds or seconds. But Dr. Anderson said that finding something that turns on within a minute was very strange.
According to her, the mysterious object was incredibly bright, smaller than the Sun and emitted highly polarized radio waves, which indicates that the object has an extremely strong magnetic field.
Dr. Hurley-Walker said the observations are consistent with a predicted astrophysical object called a super-long period magnetar. “This is a type of slowly rotating neutron star that has been theoretically predicted to exist,” she said. “But no one expected the direct detection of such a star because we didn’t expect them to be as bright. Somehow it converts magnetic energy into radio waves much more efficiently than anything we’ve seen before.”
Dr. Hurley-Walker is now monitoring the object with MJ to see if it will turn on again. “If that happens, there are telescopes all over the Southern Hemisphere and even in orbit that can point right at him,” she said.
Dr. Hurley-Walker plans to find more of these unusual objects in the MJ’s vast archives. “The increase in the number of detections will allow astronomers to understand whether this was a rare isolated case or a huge new population that we had not noticed before,” she said.
MWA Director Professor Stephen Tingay said the telescope is a precursor instrument to the Square Kilometer Array, a global initiative to build the world‘s largest radio telescopes in Western Australia and South Africa.
“The key to discovering this object and studying its detailed properties is the fact that we were able to collect and store all the data obtained by MWA over almost the past decade at the Pawsey Supercomputing Research Center. Being able to view such a dataset when you find an object is unique in astronomy,” he said. “Undoubtedly, there are many more gems to be discovered in the coming years by MWA and SKA.”
The Murchison Wide Field Array is located at the Murchison Radio Astronomy Observatory in Western Australia. The observatory is operated by CSIRO, Australia’s national science agency, and was established with the support of the Australian and Western Australian governments. We recognize Wajarri Yamatji as the traditional owners of the observatory grounds.
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