Professor Mark Hannam
Head of Gravitational Physics Group
Director of the Gravity Exploration Institute
I study black holes and gravitational waves. Black holes are the most extreme objects in the universe (that we know of!), and gravitational waves are the opposite: they are so weak that they can only be detected with the most sensitive instruments that humans have ever built; when they were measured for the first time in 2015, it was one hundred years after Einstein first prediced them. Those signals were produced by black holes colliding with each other. My research has focussed on understanding and modelling the gravitational-wave signals from just such events, and the models we devevlop are used to measure the properties of those events -- how massive were the black holes, how fast were they spinning, and where were they in the universe? These measurements are filling in details in our understanding of how black holes form, and, in turn, about the past, present and future of our universe.
I studied at Waikato and Canterbury Universities in New Zealand, and at the University of North Carolina at Chapel Hill, in the USA. During my PhD I numerically solved the equations necessary to provide initial conditions for simulations of collisions of black holes.
After I completed my PhD in 2003, I embarked on a research world tour, stopping at the University of Texas at Brownsville; the Friedrich-Schiller-University in Jena, Germany; University College Cork, Ireland; and the University of Vienna, Austria. In 2010 I came to Cardiff as an STFC Advanced Fellow, and became a professor in 2015. In 2015 I was also awarded an ERC Consolidator Grant to study precessing binary black holes.
I teach the 4th-year course, "Introductinon to General Relativity".
Numerical Relativity and Gravitational-Wave Astronomy
Numerical Relativity involves solving Einstein's equations of general relativity on a computer, and one of the most exciting current applications is to model two black holes that orbit each other, inspiral together, and merge to form a single black hole. The reason this is so topical is that these simulations are the only way to predict the gravitational-wave signal from black-hole mergers, which produced the first direct gravitational-wave observations in 2015 -- and indeed, many more detections since then. Our signal models were used to decipher the properties of those first direct gravitational-wave detections. As the detectors become more sensitive, and we are able to extract more detailed information from gravitational-wave signals, we need to move beyond the simple approximate models that we have developed so far, and construct precision models that capture all of the physics of black-hole mergers.
- Numerical relativity
- Gravitational waves
- Black holes
- Waveform modelling
- Astrophysical implications of gravitational-wave observations
My previous PhD students at Cardiff were Patricia Schmidt (graduated 2014), Sebastian Khan (2016), and Gernot Heissel (2017).