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Anna Heffernan

Postdoc Research Fellow Lvl Ii

School Of Mathematics & Statistics

Tel:
Email: anna.heffernan@ucd.ie

Biography

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.

Professional

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

Associations

Association: Institute of Physics, Function/Role: Member
         

Employment

Employer: European Space Agency
Position: Research Fellow in Fundamental Physics

Education

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
   

Outreach Activities

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

UCD New Era and Access courses tutor, 2009-2013: courses for 2nd level students from underprivileged schools and mature students who previously had not the opportunity to attend 3rd level education. 

   

Publications

     

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. Available Online [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. Available Online [DOI] [Details]
 

Conference Publications

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 Available Online [Details]
                           

Dissertations/Theses

Anna Heffernan (2013) The Self-force Problem: Local Behaviour of the Detweiler-Whiting Singular Field. Dissertations/Theses Available Online [Details]
                 

Electronic Publication

Anna Heffernan, Adrian C. Ottewill, Niels Warburton, Barry Wardell, Peter Diener (2017) Accelerated motion and the self-force in Schwarzschild spacetime. Electronic Publication Available Online [Details]
                                                                                     

Research

Research Interests

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.

In 2015, gravitational waves were directly detected using laser interferometry by the U.S. detector LIGO, resulting in the 2017 Nobel prize.  The European detector, VIRGO, has since also detected gravitational waves in agreement with more recent LIGO detections.  Now that direct detection is possible, one can use these detected waveforms to extract information about their origin.  This has resulted in several detections of binary black holes which immediately communicated and continues to communicate new observations to the community, e.g., they can exist in binaries (this had never been observed before); the masses of the black holes were larger than expected; black holes can be spinning; and that's just the beginning. Further detections will allow us to create binary black hole populations which in turn can give us information about the structure and growth of our universe; while pulsar timing array detectors as well as future ground and space-based detectors could give us a snapshot into a time less than micro seconds after the Big Bang. 

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!
 

 
 

Recent Postgraduates

Christopher Gerekos - Intern/stagaire at European Space Agency Advanced Concepts Team