For the past three years, Curtin PhD candidate Ryan Urquhart has been discovering and studying extragalactic stellar-mass black holes beyond the Milky Way. Now, the impact of his research has been celebrated at the 2018 Premier’s Science Awards, where he was named as joint winner of ExxonMobil Student Scientist of the Year.
While the term ‘black hole’ suggests an emptiness, a place where nothing happens, cosmic black holes are anything but calm. In fact, the ‘fast-feeding’ variety are monsters of mayhem. Sucking in everything within reach, they can produce energy in excess of what would be emitted by a million Suns.
Ryan Urquhart is particularly interested in this type of black hole. At the International Centre for Radio Astronomy Research (ICRAR) in Perth, he’s been combining signals captured by the world’s best telescopes to study the fastest feeding black holes in the ‘local’ Universe.
“These are rare and enigmatic objects, called ultraluminous X-ray sources, or ULXs. They’re not easy to find, but they offer ideal laboratories for testing extreme physics,” he explains.
“ULXs draw in plasma and gas, recycling the energy which can be ejected as beams of charged particles travelling near the speed of light, known as jets.
“These jets are so powerful that when they collide with surrounding gas they inflate giant bubbles of plasma, which span thousands of light years, and we study these bubbles to determine the energetics of the black hole.”
If the theory that a supermassive black hole exists at the centre of all large galaxies is correct, understanding how the in-falling matter is converted to energy in ULXs will help solve the mystery of how galaxies evolved.
As a member of the Curtin Institute of Radio Astronomy (CIRA), Urquhart has access to WA’s world-leading Murchison Widefield Array and a range of other telescopes for his research.
“I use X-ray telescopes to probe the black hole feeding process and use radio and optical telescopes to observe the giant bubbles. The radio data also probes the relativistic jets produced by the black hole.
“Using these techniques, I have been able to identify new black holes in nearby galaxies and investigate how their rapid consumption of material impacts their surroundings.”
There’s no doubt that the complexity of Urquhart’s research area is a challenge to explain. Fortunately, he’s an excellent science communicator, and has been a popular visitor to primary and secondary classrooms throughout WA, where he’s provided students with hands-on experience with optical and radio telescopes.
He was also a member of the CIRA Diversity and Equity Development Committee, which encourages gender balance and fosters equity and diversity at ICRAR.
“This is especially important in STEM fields like astronomy, where there is a known and appreciable gender imbalance.
“I encourage all students to consider career paths in STEM fields – there are exciting horizons for Australia’s next generation of scientists and astronomers,” he explains.
Urquhart’s research achievements have shone the light on CIRA as one of the nation’s leading hubs of X-ray expertise. And his success at the Premier’s Science Awards follows that of CIRA researcher Dr Thomas Russell, who was awarded ExxonMobil Student Scientist of the Year in 2015 for his research on black holes.
Urquhart is currently contributing to several national and international collaborations, including pioneering work on nuclear supermassive black holes at the centre of galaxies.
“ULX research is still rare in Australia, but it will contribute significantly to our knowledge about particle physics, black hole behaviours and galaxy evolution.”