World-first images show what the universe would look like if humans could see radio waves
The world’s first pictures of the universe in radio technicolour have been produced using a $50 million radio telescope in the Western Australian outback.
The ground-breaking Galactic and Extragalactic All-sky MWA (GLEAM) survey has created multi-coloured images of 300,000 galaxies, millions to billions of light years away, in the southern sky.
The spectacular pictures, published today by the Royal Astronomical Society, show what the universe would look like if the human eye could see radio waves.
The galaxies were observed by the Murchison Widefield Array radio telescope, located at the Murchison Radio-astronomy Observatory, 315 kilometres north-east of Geraldton.
GLEAM’s lead author, Dr Natasha Hurley-Walker, said the survey offered new insights into the enormity of the cosmos.
“When you’re looking up at the sky normally … you’re constrained as to what you can see,” she said.
“With the radio [telescope], we can peer out onto the immensity of the universe.
“We can see bright galaxies with super massive black holes and we can get this incredible picture of the sky.”
Dr Hurley-Walker is an astronomer with Curtin University and the International Centre for Radio Astronomy Research (ICRAR).
Sharing the culmination of three years of “blood, sweat, tears and supercomputers” was exciting, she said.
“People think ‘Oh astronomers, how romantic, you’re out there peering through a telescope’,” Dr Hurley-Walker said.
“A lot of my day-to-day job is running code on computers until I get it right, so it’s great to have finally got it right to share with the world.”
Using cutting-edge technology to turn up the technicolour
Dr Hurley-Walker painstakingly calibrated about 45,000 images to radio frequencies between 70 and 230 megahertz to provide the colourful catalogue of celestial bodies.
“Most radio surveys just look at a single frequency,” she said.
“This … gives them essentially a black and white image of the universe.
“What’s really cool about GLEAM is that we observe over a really wide range of frequencies.”
In simple terms, GLEAM is like going from black and white to colour television.
The three colours — red, blue and green — represent physical processes taking place in space.
“It gives us a real insight into what’s going on in the universe,” Dr Hurley-Walker said.
Remote WA location crucial to breakthrough
Dr Hurley-Walker said the MWA’s remote desert location and lack of radio interference was crucial to conducting the survey.
“It doesn’t receive any other interfering radio signals from people because the Murchison is basically empty,” she said.
“There’s no wifi, there’s no mobile phones, there’s not even any FM radio.
“When we’re trying to observe at the radio frequencies, normally this radio interference is a huge problem.
“In a remote location like the Murchison … we can observe in frequencies that have never been observed before because of the human-caused radio collusion.”
MWA director Randall Wayth said GLEAM was one of the biggest radio surveys of the sky ever assembled, and was a significant achievement.
“Large sky surveys are extremely valuable to scientists and they’re used across many areas of astrophysics, often in ways the original researchers could never have imagined,” Dr Wayth said.