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A/Prof Chris Power

I am a computational astrophysicist working on a broad range of problems in galaxy formation and cosmology. My particular interests are in dark matter – what is its nature? what kinds of observations will allow us to discriminate between alternative models? – and in how feedback from stars and black holes (i.e. deposition of energy and momentum into their surroundings) impact the formation and evolution of galaxies. Most of this work requires powerful supercomputers, and so I also have an ongoing interest in scientific high performance computing.

I obtained a BA in Theoretical Physics from Trinity College Dublin in 1999, and a PhD from Durham University in 2003. Between 2004 and 2011, I held postdoc positions in the Swinburne Centre for Astrophysics and Supercomputing in Melbourne (2004-07) and with the Theoretical Astrophysics Group at the University of Leicester (2008-11). I have been at ICRAR/UWA since 2011, initially as a research assistant professor and, since 2014, as a research associate professor and ARC Future Fellow. Here at ICRAR/UWA, I lead the Computational Theory and Modelling Group, a team of approximately 20 staff, postdocs and students working on a variety of simulation, modelling, and statistical problems in galaxy formation and cosmology.

I am an associate member of the ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO), and am a Chief Investigator for the new ARC CoE CAASTRO3D. I also serve on various committees, including the Astronomical Society of Australia council, the Australia Telescope Time Assignment Committee (TAC), the Astronomy Supercomputer Time Allocation Committee (ASTAC), and the Australian e-Research Advisory Committee (AeRAC).


Chris Power
THE INTERVIEW BELOW WAS CONDUCTED IN 2014

What are you working on now?

I am building computer models of low-mass galaxies, similar to the satellite galaxies we find orbiting the Milky Way today but as they were in the early Universe. I want to understand how the manner in which stars form early in the formation history of such low-mass galaxies influence the properties that we can observe at the present day. In particular, I am interested in whether or not the explosive deaths of massive stars as supernovae can lead to the disruption of some galaxies and not others. This is interesting because our current theories of galaxy formation suggest that there should be many more satellite galaxies than we observe around the Milky Way. The models I am working on could (at least partially) help to reconcile theory and observation.

What got you into astronomy?

The night sky. I grew up in the countryside outside of Dublin in the Republic of Ireland and some of my earliest memories are of crisply clear dark skies (unusual for Ireland) and being mesmerized by the stars, their patterns and the twinkling colours. As I got older I devoured books and magazines on astronomy, I knew the Northern sky like the back of my hand, and there was no question that I would be anything other than an astronomer when I grew up.

Why is your work important for ICRAR?

Astronomy is peculiar in that it’s difficult to do experiments. That’s why astronomers build large telescopes and observe enormous numbers of galaxies, in the hope that we can see enough examples of galaxies to piece together what’s going on. However, whilst we can’t go into a physical lab and smash galaxies together, we can go into a virtual lab – a supercomputer – and carry out these kinds of experiments. These numerical experiments help us to interpret observations and to understand their astrophysical significance. This is where I believe the importance of my work lies, and it was a major factor in my decision to join ICRAR – to work directly with teams of observers to make sense of the results of current and future galaxy surveys, and to learn a lot about why the Universe is the way it is.

Where were you before you came to work for ICRAR?

I did my PhD at Durham University in the UK, graduating in 2004, and then held a couple of postdoc positions, one at the Centre for Astronomy and Supercomputing at Swinburne University in Melbourne, the other with the Theoretical Astrophysics Group at the University of Leicester in the UK. I joined ICRAR in early 2011.

What’s your favourite part of your work?

There are a few things I particularly enjoy, and it’s hard to pick a favourite. I love being an astronomer and thinking about galaxies and black holes and the origin and fate of the Universe – this is something I’ve wanted to do since I was a child; I find the process of doing science – the problem solving, the testing of ideas, the scrutiny of the evidence – hugely satisfying; and, as someone who has always been curious about different cultures and customs, I love that astronomy is so international, giving me the chance to work with people from many different countries around the world.

What do you think is the most exciting thing about astronomy today?

That’s a difficult one – so many to choose from! I’ve had a long-standing interest in the nature of dark matter, which makes up about 80% of the matter content of the Universe. However, the precise physical nature of this dark matter is still unknown. Astronomers have a preferred candidate, which we call Cold Dark Matter, while particle physicists have a number of potential candidates, but we’re still not sure. Fortunately, it looks like we can use and detailed observations of satellite galaxies and stars around the Milky Way to test carefully our theories of dark matter. By comparing with computer models of the Milky Way and its satellites, we should be able to place stringent limits on what the dark matter can be, and answer one of the key problems in astrophysics, particle physics and cosmology.

 

What is your opinion on inspiring the next generation of scientists?

I think it’s vitally important that we live in a scientifically-literate society. If you look at the kind of challenges that the world faces and the kind of tools that humanity requires to tackle them successfully, then we need not only scientists and engineers to ensure that we can do this, but we also need the wider public to understand what is being done and why it is being done. More broadly, the kind of intellectual tools that scientific training offers – to question and to critically assess the evidence – are crucial in shaping the kind of society future generations will live in.

 

What is the biggest thing that you’ve ever created in a computer?

The biggest thing would be a model of the Universe a few billion light years across, to study the spatial distribution of massive clusters of galaxies. The coolest thing would be a super-massive black at the centre of a galaxy like the Milky Way and watching it as it gobbles up gas and stars from its surroundings and belching out powerful winds in response!