The UCD Relativity Group currently consists of two permanent faculty members, a Royal Society-Science Foundation Ireland University Research Fellow, an adjunct professor, and six PhD students.

## Faculty

### Adrian Ottewill

I have over 30 years Faculty experience at Oxford University and UCD with a long record of research supervision of PhD and postdoctoral students in classical and quantum gravity with particular emphasis on gravitational wave astronomy, quantum field theory and wave propagation in curved space-time. I am a Fellow of the Institute of Physics and Royal Astronomical Society and has been a Member of the Royal Irish Academy for over 20 years.

University website

### Barry Wardell

I am an Assistant Professor working in the School of Mathematics and Statistics at University College Dublin. My main research interests involve the study of Black Holes and Cosmic Strings, from both numerical and analytical perspectives. I am also interested in other aspects of General Relativity, Astrophysics, and Computational Science.

Personal website

University website

### Niels Warburton

I am a Royal Society–Science Foundation Ireland University Research Fellow. My research centres around modelling gravitational wave emission from compact binary systems, with a particular emphasis on small mass-ratio systems. I model these binaries using black hole perturbation theory, a method that models the system as a perturbation to the exact black hole solutions of General Relativity. These so-called extreme mass-ratio inspirals (EMRIs) are key sources for the future space-based gravitational wave detector LISA.

I am an active member of the LISA consortium where I co-chair the Waveform Working Group and am a coordinator for the EMRI waveform Working Package.

Personal website

University website

## Sarp Akcay

I am an Ad Astra Fellow with 10 years of postdoctoral experience in the UK, France, Ireland, and Germany. I was an IRC postdoc between 2014 and 2016.

I am a member of both the LIGO-Virgo Collaboration and the LISA Consortium. My research interests are mathematical and computational general relativity with specific focus on modelling compact binary inspirals and mergers that are detectable by either ground-based or space interferometers. I have done work in the fields gravitational self-force and effective-one body theory. I am part of a collaborative effort that is currently building a waveform approximant for parameter estimation with LIGO-Virgo. I have also been in the review committees for the other similar approximants.

### Marc Casals (adjunct)

I am a Research Professor at the Centro Brasileiro de Pesquisas Físicas (CBPF) in Rio de Janeiro, Brazil, and an Adjunct Lecturer at the School of Mathematics and Statistics at UCD. I am a researcher in General Relativity and in Quantum Field in curved spacetimes, with a particular interest in classical and quantum black holes. On the classical side, my work ranges from black hole stability properties to black hole binary inspirals and gravitational waves. On the quantum side, my work covers Hawking radiation, quantum backreaction and higher-dimensional black holes.

Personal website

## Postdoctoral Researchers

### Vojtěch Witzany

I have been a Marie Skłodowska-Curie fellow at UCD since September 2020. Before that, I did my PhD at ZARM, University Bremen, and then a two-year postdoc at the Astronomical Institute of the Czech Academy of Sciences in Prague. I am a theoretical physicist with a stress on classical relativistic gravity and relativistic astrophysics. Similar to other people in the group, I am currently interested in the problem of two bodies in relativity and modeling their gravitational-wave inspirals. Most recently, I have been working on corrections to the two-body motion due to the spin of the bodies and other perturbations.

Google Scholar profile

ArXiv papers

## PhD Students

### Leanne Durkan

My research focuses on Black Hole Perturbation Theory, Extreme Mass Ratio Inspirals of Binary Black Hole systems and Gravitational Self-Force. In my current project I am exploring the gauge transformation between Regge-Wheeler and Lorenz gauge perturbations. While the former is easier to work with, the latter is crucial for self-force calculations.

Graduate of Part III, 2018, St Catherine’s College, Cambridge. 2019 winner of UCD’s Thesis in 3 competition.

### Benjamin Leather

I am a Royal Society funded PhD Student. My research focuses on modelling gravitational self-force from systems from extreme-mass-ratio inspirals (EMRIs) using black hole perturbation theory. Here the smaller body is treated as a perturbation of an exact black hole solution and this leads to a solution in terms of a formal power series in the mass ratio. For the future space-based gravitational wave detector, LISA, it is necessary to consider up to second-order in the mass ratio. In particular, I am interested in how to compute these second-order waveforms for systems where the smaller body is in an eccentric orbit around the primary black hole.

MPhys Physics with Theoretical Physics graduate from the University of Manchester.

### Philip Lynch

I am an Irish Research Council funded PhD student in the School of Mathematics and Statistics in UCD. My research focuses on the evolution of binary systems consisting of a stellar mass black hole/ neutron star, and a supermassive black hole, known as Extreme Mass Ratio Inspirals (EMRIs). In particular, I am interested in how the secondary object’s trajectory can be modelled with various techniques such as the method of osculating orbital elements, near identity transformations, and the two-timescale approach. The goal of this work is to produce computationally efficient waveform models for use with the upcoming LISA mission.

### Josh Mathews

My PhD is funded by the Irish Research Council. I am currently working on modelling the effects of a spinning secondary body on EMRI waveforms. I also have a keen interest in scientific outreach.

In my spare time I enjoy surfing, judo and generally being outdoors.

### Conor O’Toole

I am an Irish Research Council funded PhD student. The focus of my research is on the development of tools necessary for accurate waveform template generation for Extreme Mass Ratio Inspirals (EMRIs). The primary means of modelling such systems is the self-force approach, where the small object is treated as a perturbation to the background spacetime. I am developing a method to determine the perturbation based on the calculation of the Green Function in a black hole background space time by means of a characteristic initial value problem. This method will enable for self-consistent evolution of the inspiral, and can be implemented with relative ease for generic orbits, unlike other methods which are computationally expensive on anything more complex than circular orbits.

### Kevin Kiely

I am an Irish Research Council funded PhD student working on devising new functional methods that will allow one to generate fast and accurate models of the gravitational waves emitted by an extreme mass ratio inspiral.

## Former members

- Cormac Breen – PhD student now lecturer at TU Dublin
- Sam Dolan – Irish Research Council postdoc now a senior lecturer at the University of Sheffield, UK
- Anna Heffernan – PhD student and Marie Skłodowska-Curie postdoctoral fellow. Now an associate postdoc researcher at Perimeter Institute and a postdoc fellow at the University of Guelph, Canada
- Seth Hopper – visiting postdoc now a lecturer at Earlham College, USA
- Chris Kavanagh – PhD student now a postdoc at the Albert Einstein Institute
- Paddy Nolan – PhD student now in industry
- Peter Taylor – PhD student and Irish Research Council Marie Skłodowska-Curie Actions COFUND postdoctoral fellow now a lecturer at Dublin City University