General Relativistic Astrophysics

Lead Research Organisation: University of Southampton
Department Name: Sch of Mathematical Sciences

Abstract

We are entering an era of high-precision astronomy, both electromagnetic and gravitational. The first generation of highly sensitive gravitational-wave detectors have reached design sensitivity and are being upgraded using advanced technology. LOFAR is on-line, providing significant improvements in radio timing precision. Future advances associated with the SKA in radio, the Einstein Telescope and the space based detector eLISA for gravitational waves will complement current quality X-ray observations, and will allow us to improve our understanding of the Universe significantly. To benefit maximally from these improvements, we need to improve our current models of a range of phenomena involving compact objects. Better quality theory is needed both to detect the various signals and to probe as much of the relevant physics as possible.

This research proposal builds on the Southampton Gravity Group's expertise in black hole, neutron star and gravitational-wave astrophysics, and is aimed at developing a deeper understanding of the dynamics of black holes and neutron stars, the associated observational signatures and how these signals can be used to provide information about the involved physics. The programme is of a highly interconnected nature with four different themes requiring similar methodology (e.g. general relativistic perturbation theory or numerical simulations) and physics input (e.g. superfluidity, magnetic fields or gravitational radiation reaction). The overall aim is to develop significantly improved models that can be tested against future high-precision observations in a range of channels.

Neutron stars are unique astrophysical laboratories, the modelling of which requires much poorly known physics. In order to investigate their properties, one must combine supranuclear physics with magnetohydrodynamics, a description of superfluids and superconductors, potentially exotic phases of matter like a deconfined quark-gluon plasma and, of course, general relativity. Achieving a better understanding of neutron star dynamics is one of the key aims of this proposal. We will carry out three projects, focused on the dynamics and evolution of neutron stars. The proposed work is of immediate relevance for gravitational-wave physics, leading to astrophysically motivated signal searches, and provides useful insights into problems relevant for electromagnetic observations. We aim to construct accurate models of neutron star dynamics that can be tested against recent observations of oscillations associated with magnetar giant flares, and which will inform future targeted searches for r-mode oscillations in fast spinning neutron stars. We will provide improved models of the enigmatic glitches and other timing phenomena seen in radio pulsars. We also plan to carry out nonlinear simulations of neutron star mergers with an unprecedented level of realism, exploring electromagnetic counterparts to the emerging gravitational waves.

Inspiralling binaries are intrinsically the strongest sources of gravitational waves in the Universe. Gravitational waveforms from such events are extremely efficient probes of the strong gravity near black holes, and their detection promises to allow accurate tests of gravitational theory in its most extreme domain. In order to realise this promise we need a good theoretical understanding of relativistic radiation-reaction effects. Recent progress on the problem of the gravitational self-force provides significant momentum for work in this area. Building on this, we will explore the promising synergy between self-force calculations, numerical relativity and post-Newtonian theory, in order to inform a universal model of binary inspirals across the entire range of mass ratios and spin rates.

Planned Impact

This summary identifies some of the routes by which our astrophysics research programme will impact upon the wider world, including the general public, other scientific disciplines, and the technology sector.

COMMUNICATIONS AND ENGAGEMENT: The Southampton Gravity Group has a consistent track record of engaging with the public to communicate the latest and most exciting aspects of its research. These have included public talks, lectures to school students, coordination of a Royal Society Summer Exhibition and contact with Members of Parliament. The Group plans to enhance this activity, with STFC-funded researchers playing a leading role in exploring new dissemination outlets, including "Meet the Astronomer" sessions and the construction of interview/video clips for electronic circulation. The most exciting research advances will be promoted via the University Press office, whose help in publicising recent breakthroughs played a role in several articles on Southampton research appearing in the press, including in National Geographic, New Scientist and The Daily Mail.

COLLABORATION: The richness of the physics needed to model compact objects naturally leads to the possibility of developing collaborations with traditionally disparate scientific disciplines. In particular, there is scope for collaboration with experts in low-temperature physics, whose knowledge of condensed matter many prove invaluable in understanding neutron star interiors. Equally exciting is the possibility of exploiting links between the black hole inspiral problem and the problem of nonlinear electromagnetic pulse propagation in an optical fibre. Steps will be taken to explore these exciting overlaps, which will include the organisation of focused study groups to explore the key issues.

EXPLOITATION AND APPLICATION: The theoretical work of the Group is intimately linked to several large experimental efforts, whose innovative technological development impacts on industry, with spin-offs including satellite stabilisation systems, seismic isolation, the construction of large vacuum cavities, and laser stabilisation. As well as providing motivation for these efforts, the theoretical modelling of the Group is crucial in making informed decisions as to how changes in expenditure and project duration impact on science capabilities.

CAPABILITY AND RESOURCE: We are rapidly approaching an era of precision astronomy, with new electromagnetic and gravitational experimental projects under rapid development. The young researchers that the Group hopes to recruit will receive training in exploiting these opportunities that few other groups could provide. Previous Group members have already gone on to secure prestigious academic appointments. Beyond the world of academia, the skill sets that the researchers would acquire would also equip them to play important roles in the wider community, as is reflected in the success of previous members in gaining attractive jobs in industry. The University recently established a Research Development and Graduate Centre that will help systematize this training, and enable the Group to continue to produce well-rounded researchers with skills well suited to demands of the 21st Century economy and academia.

Publications

10 25 50
 
Description Continued to contribute to the worldwide effort to detect - and extract information from - astrophysical gravitational waves. Contributed to the analysis of, and theory behind, the first neutron star merger detected in August 2017. Increased engagement with the LISA project aimed at detecting low-frequency gravitational waves with a space based antenna.
Exploitation Route This work is ongoing.
Sectors Education

 
Description BEPE-FAPESP fellowship (Brazil)
Amount R$ 86,097 (BRL)
Organisation São Paulo Research Foundation (FAPESP) 
Sector Public
Country Brazil
Start 01/2018 
End 01/2019
 
Description MArie Curie Fellowship
Amount € 251,858 (EUR)
Organisation European Union 
Sector Public
Country European Union (EU)
Start 10/2016 
End 09/2019
 
Description University research fellowship
Amount £217,724 (GBP)
Funding ID UF160110 
Organisation The Royal Society 
Sector Charity/Non Profit
Country United Kingdom
Start 10/2017 
End 09/2022
 
Description Gravitational-wave Excellence through Alliance Training (GrEAT) Network with China 
Organisation University of Glasgow
Department Institute for Gravitational Research
Country United Kingdom 
Sector Academic/University 
PI Contribution Consortium of UK gravitational-wave groups to provide training and public outreach in China. Soton co-leads on modelling and data analysis. Funded by SFTC as ST/R002770/1.
Collaborator Contribution The project also involves outreach and experimental aspect for both ground- and space-based interferometers.
Impact The collaborations is starting 2018 so is still in the set-up phase.
Start Year 2018
 
Description LIGO-Virgo-Kagra Scientific collaboration 
Organisation California Institute of Technology
Country United States 
Sector Academic/University 
PI Contribution Prof Ian Jones continues to be a member of the LIGO collaboration, particularly active in the continuous wave search group.
Collaborator Contribution The LIGO scientific collaboration is the umbrella organisation for the worldwide search for gravitational waves, the associated data analysis and interpretation of results.
Impact The collaboration publishes a large number of high-profile papers each year.
 
Description LIGO-Virgo-Kagra Scientific collaboration 
Organisation Cardiff University
Country United Kingdom 
Sector Academic/University 
PI Contribution Prof Ian Jones continues to be a member of the LIGO collaboration, particularly active in the continuous wave search group.
Collaborator Contribution The LIGO scientific collaboration is the umbrella organisation for the worldwide search for gravitational waves, the associated data analysis and interpretation of results.
Impact The collaboration publishes a large number of high-profile papers each year.
 
Description LIGO-Virgo-Kagra Scientific collaboration 
Organisation Massachusetts Institute of Technology
Country United States 
Sector Academic/University 
PI Contribution Prof Ian Jones continues to be a member of the LIGO collaboration, particularly active in the continuous wave search group.
Collaborator Contribution The LIGO scientific collaboration is the umbrella organisation for the worldwide search for gravitational waves, the associated data analysis and interpretation of results.
Impact The collaboration publishes a large number of high-profile papers each year.
 
Description LIGO-Virgo-Kagra Scientific collaboration 
Organisation University of Birmingham
Country United Kingdom 
Sector Academic/University 
PI Contribution Prof Ian Jones continues to be a member of the LIGO collaboration, particularly active in the continuous wave search group.
Collaborator Contribution The LIGO scientific collaboration is the umbrella organisation for the worldwide search for gravitational waves, the associated data analysis and interpretation of results.
Impact The collaboration publishes a large number of high-profile papers each year.
 
Description LIGO-Virgo-Kagra Scientific collaboration 
Organisation University of Birmingham
Country United Kingdom 
Sector Academic/University 
PI Contribution Prof Ian Jones continues to be a member of the LIGO collaboration, particularly active in the continuous wave search group.
Collaborator Contribution The LIGO scientific collaboration is the umbrella organisation for the worldwide search for gravitational waves, the associated data analysis and interpretation of results.
Impact The collaboration publishes a large number of high-profile papers each year.
 
Description Newton STFC Capacity Building with LIGO-India 
Organisation Indian Initiative in Gravitational-wave Observations
Country India 
Sector Charity/Non Profit 
PI Contribution Southampton are lead on modelling and outreach efforts in a collaboration between a consortium of UK gravitational wave groups and LIGO India.
Collaborator Contribution In the initial phase, provided a range of outreach material and contributed to the formation of the collaboration.
Impact Still at the set-up stage.
Start Year 2018
 
Description Newton STFC Capacity Building with LIGO-India 
Organisation University of Glasgow
Department Institute for Gravitational Research
Country United Kingdom 
Sector Academic/University 
PI Contribution Southampton are lead on modelling and outreach efforts in a collaboration between a consortium of UK gravitational wave groups and LIGO India.
Collaborator Contribution In the initial phase, provided a range of outreach material and contributed to the formation of the collaboration.
Impact Still at the set-up stage.
Start Year 2018
 
Description Einstein talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Schools
Results and Impact Talk on Einstein and gravity In Bangalore, India, organised by ICTS in Bangalore
Year(s) Of Engagement Activity 2017
 
Description Royal Society Summer exhibit 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Gravitational wave exhibit at Royal Society Summer Exhibit 2017 and special event at Science Museum, London.
Year(s) Of Engagement Activity 2017
 
Description Science comedy 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Prof Andersson participated in Radio 4 Infinity Monkey Cage episode on gravitational waves.
Year(s) Of Engagement Activity 2018