School Of Mathematics & Statistics
I am currently a Marie Curie fellow at University of Florida and University College Dublin, where I work with Profs. Bernard Whiting, Clifford Will and Adrian Ottewill. My research involves using analytical perturbative methods in black hole physics, alternative theories of gravity as well as more experimental gravitation like that required for global navigation satellite systems. Previous to my current position, I worked as a research fellow in fundamental physics at the European Space Agency, in their Advanced Concepts team - a think tank for ESA which seeks to identify and research scientific developments that can or will impact future space systems.
Previous to my time at ESA, I carried out my PhD in General Relativity, "The Self-force Problem: Local Behaviour of the Detweiler-Whiting Singular Field", at University College Dublin under the supervision of Prof. Adrian Ottewill. The self-force is the leading method for tackling gravitational waveform modelling in the scenario of a binary black hole with extremely different masses; a main target for LISA, the future space-based gravitational wave detector to be launched by ESA. During my PhD, I also completed MSc. courses which led to my Higher Diploma in computational sciences.
Prior to my PhD, I received my BSc. in Theoretical Physics from University College Dublin, where I received first class honours and finished first in my class. I followed this with a MSc. in Quantum Fields and Fundamental Forces from Imperial College London. There I completed my dissertation, The Decoherence Histories Approach to Quantum Theory under the supervision of Prof. J. Halliwell, finishing in the top 4 of my class with a distinction.
Honours and Awards
| Year: 2015.
Title: Marie Sklodowska-Curie Global Fellowship
| Year: 2015.
Title: Winners of Global Trajectory Optimization Competition
| Year: 2013.
Title: Institute of Physics Gravitational Physics Group Thesis Prize
| Year: 2012.
Title: Short Term Scientific Mission for Black Holes in a Violent Universe
| Year: 2012.
Title: CR Barber Trust Grant
| Year: 2012.
Title: Research Student Conference Fund
| Year: 2006.
Title: Marie Curie Grant
| Year: 2005.
Title: IRCSET Postgraduate Scholarship
|Association: Institute of Physics, Function/Role: Member|
| Employer: European Space Agency
Position: Research Fellow in Fundamental Physics
| Year 2003 Institution: University College Dublin
Qualification: BSc. (1st Class) Hons. - 1st place in program Subject: Theoretical Physics
| Year 2004 Institution: Imperial College London
Qualification: MSc (With Distinction) Subject: Quantum Fields and Fundamental Forces
| Year 2007 Institution: University College Dublin
Qualification: HDip Subject: Computational Science
| Year 2013 Institution: University College Dublin
Qualification: PhD Subject: General Relativity
|Invited seminar speaker in the Nobel Prize series at the Institute for Learning in Retirement (ILR), Florida, March 2018.|
|Moderator for the official LIGO VIRGO live youtube Q&A session that served the public in between and after the panel discussions as part of the official announcement of the first gravitational and electromagnetic detection of a binary neutron star: LIGO VIRGO binary neutron star announcement|
| Speaker at "Talk Science with Her" public outreach advent, Gainesville, Florida in 2017 and 2018
|Judge at Howard W. Bishop Middle school science fair, 2016, and UF Graduate Student Research Day poster competition, 2017.|
|Participant in Space Girls Space Women: http://www.spacewomen.org/|
|ESA Advanced Concepts Team research fellow interviews: http://www.esa.int/About_Us/Careers_at_ESA/Post_doc_videos_the_ACT_think-tank|
Peer Reviewed Journals
|Heffernan, A,Ottewill, A,Wardell, B (2012) 'High-order expansions of the Detweiler-Whiting singular field in Schwarzschild spacetime'. Physical Review D - Particles, Fields, Gravitation and Cosmology, 86 :104023. [DOI] [Details]|
|Heffernan, A, Ottewill, A.C and Wardell, B (2014) 'High-order expansions of the Detweiler-Whiting singular field in Kerr spacetime'. Physical Review D - Particles, Fields, Gravitation and Cosmology, 89 :024030. [DOI] [Details]|
|Izzo, D; Hennes, D; Märtens, M; Getzner, I; Nowak, K; Heffernan, A; Campagnola, S; Yam, CH; Ozaki, N; Sugimoto, Y (2016) GTOC8: Results and Methods of ESA Advanced Concepts Team and JAXA-ISAS 26th AAS/AIAA Space Flight Mechanics Meeting, Napa, CA. Paper AAS 16-275 [Details]|
|Anna Heffernan (2013) The Self-force Problem: Local Behaviour of the Detweiler-Whiting Singular Field. Dissertations/Theses [Details]|
|Anna Heffernan, Adrian C. Ottewill, Niels Warburton, Barry Wardell, Peter Diener (2017) Accelerated motion and the self-force in Schwarzschild spacetime. Electronic Publication [Details]|
My main research interest lies in gravitational waves; ripples in spacetime as predicted by Einstein's theory of relativity. Strong evidence of their existence was discovered in 1974 with the Hulse-Taylor binary pulsar - two neutron stars in the very long process of inspiralling into each other. On discovering the system, it was observed the system was losing energy - exactly the amount of energy predicted to be lost by gravitational wave radiation, a discovery which won the Nobel prize in 1993.
The excitement grows more when one looks at the binary neutron star merger that was seen by both gravitational wave detectors and a plethora of telescopes from the electromagnetic spectrum (think gamma rays, x-rays, visible light, radio waves). Receiving 2 types of radiation from an event resulted in an explosion of data that will be analysed for years to come, giving key insights not only into general relativity but the inner workings of neutron stars and in future detectors, all the nuclear and gravitational physics that determines their equation of state.
And this is only the beginning ...
So where do I fit in? Well, to make such detections, gravitational wave detectors require waveforms - they need to know what they're looking for, or at least it helps in finding the signal. But once the signal is found, waveform models allow us to extract information about the event that created them. For ground based detectors, I have, with collaborators, being working on producing the waveform for scalar-tensor gravity, an alternative theory of gravity where the gravitational constant, G, is not constant. By producing waveforms for alternative theories of gravity, we can carry out decisive tests with the gravitational wave detectors to capture any departure from classical general relativity. Such tests in the strong gravity field regime will be paramount to carrying out conclusive test of general relativity with the detectors.
In 2034, ESA is scheduled to launch a space-based gravitational wave detector, LISA, which will see sources in a different frequency band to the current ground based detectors. The beauty of going to space for gravitational wave detection is the removal of the noisy Earth atmosphere, from people, trains, planes and autombiles affecting your detector to seismic noise; you also pick up a vacuum for free! One of the sources LISA will see, that is not visible on Earth is EMRIs (Extreme Mass Ratio Inspirals), these are expected to form when a "small" stellar mass black hole falls into the grasp of a massive black hole (think a million times the mass of the sun). Currently we do not know what the waveforms will look like for such a system, but that's okay, we have time :). The self-force method expands Einstein's field equations in the mass ratio to obtain more easily solvable equations - one of the issues that arises is the singularity one finds at the centre of the inspiralling, smaller, black hole. I've done substantial work using the Detweiler-Whiting singular field, to assist in the safe removal of this singularity and faster convergence of numerical simulations; however this is just one of many different issues that need resolving to produce viable waveforms. With a dedicated community, CAPRA, there are several groups scattered across the globe, including Dublin and Florida, working to solve this problem and produce waveforms in time for the LISA launch. It's gonna be exciting folks!
|Christopher Gerekos - Intern/stagaire at European Space Agency Advanced Concepts Team|