Investigations in Gravitational radiation

Lead Research Organisation: Cardiff University
Department Name: School of Physics and Astronomy

Abstract

Einstein's General Theory of Relativity (GR) predicts that dynamical systems in strong gravitational fields will release vast amounts of energy in the form of gravitational radiation. Gravitational waves are ripples in the fabric of spacetime and travel from their sources at the speed of light, carrying information about physical processes responsible for their emission, obtainable in no other way. They are among the most elusive signals from the deepest reaches in the Universe. Experiments aimed at detecting them have been in development for several decades, and are now reaching sensitivity levels where detection is expected within a few years.

The worldwide network of interferometric detectors includes the German-UK GEO600, the French-Italian Virgo, the American Laser Interferometer Gravitational-Wave Observatory (LIGO) and is being enhanced with a new detector under construction - KAGRA in Japan. The former detectors have all reached sensitivities close to their design goals and have taken the most sensitive data to date. Cooperation amongst different projects enables continuous data acquisition, with sensitivity to a wide range of sources and phenomena, over most of the sky.

Data from GEO, LIGO and Virgo, have already increased our understanding of astronomical phenomena. Search for gravitational waves at the times of 154 gamma-ray bursts has allowed the best ever exclusion distances and provided evidence for extra-Galactic sources of soft-gamma repeaters. The distance reach for binary black holes in the most recent runs is 300 Mpc and the rate upper limits are now very close to that expected in some of the astrophysical models. The search for gravitational waves from the Vela pulsar has set an upper bound on the strength of radiation that is significantly below that expected from the observed spin down rate of the pulsar, corresponding to a limit on the star's ellipticity of a part in a thousand.

While recent and current observations may produce detections, there can be no guarantees. However, there is great confidence that the advanced detectors currently in construction will routinely observe gravitational waves. The advanced LIGO detectors are based on the quasi-monolithic silica suspension concept developed in the UK for GEO 600 and on the high power lasers developed by our German colleagues in GEO 600. The Advanced Virgo detector also uses a variant of the silica suspension technology. The Cardiff and Glasgow groups have initiated and led searches for astronomical sources, thanks to the algorithmic and analysis effort that has been supported since the first data taking runs began eight years ago.

We propose a programme that leads to full exploitation of data from Advanced LIGO (aLIGO), building on both continuing operation of GEO600 and analysis of data taken in the most recent LIGO/Virgo science runs. In particular, we will model binary black hole mergers and carry out deep searches for
* coalescing binary neutron stars, neutron star-black hole binaries, and black hole binaries
* bursts of gravitational waves that may originate from supernovae,
* continuous signals from pulsars and other rotating neutron stars,
* gravitational waves detected by cross-correlation methods, including a cosmological background.

In parallel, we propose detector research and development. Detector sensitivity is mainly limited by thermal noise associated with the substrates of the mirrors, their reflective coatings, and their suspension elements, as well as by noise resulting from the quantum nature of the light used in sensing. Our research is targeted towards making innovative improvements in these areas. We have major responsibilities for the silica suspensions in aLIGO, and in the development of enhancements and upgrades to the aLIGO detectors, in the areas of mirror coatings for low thermal noise, silicon substrates, cryogenic suspensions and improved interferometer topologies to combat quantum noise.

Planned Impact

There are numerous beneficiaries from our proposed research in gravitational waves, including industry, other academic disciplines, schools, science centres, museums and the general public. Materials, techniques and computational software created during the design and manufacture of gravitational wave detectors and the analysis of their data, have found numerous uses and applications in industry and other fields of academic research. E.g. the Triana software package that we developed has been used on many industrial and interdisciplinary collaborative projects to date, including: BDWorld (UK); GridLab, CoreGRID and Provenance (EU); GriPhyN and Pegasus (USA). Further, our studies of mirror coating thermal noise have played a key role in the Stanford-Scotland Photonics Innovation Collaboration, designed to capitalise on leading research in the photonics sector.

Our novel oxide bonding technology is the subject of contract research studies with optics companies in the UK and Germany, and a KTP is funded in the UK to transfer the technology in detail to a UK company specialising in the construction of optical components. We are also implementing our planned extensive knowledge exchange activities ranging from optics and engineering to a study of cell behaviour and response to nano-mechanical stimulation, an area of importance for wound healing. The technology for the thin, strong fused silica fibres supporting the 40kg aLIGO mirrors masses has led to partnerships with industry on novel all-silica gravimeters for the oil industry. To achieve our goals we are working closely with local Research & Enterprise and Business Development staff at Glasgow University, and the broader SUPA KT team, in establishing and maintaining collaborations with current and possible future beneficiaries and in the setting up and management of non-disclosure agreements and applications for patents. Thus we will ensure that future knowledge exchange opportunities are identified early and exploited fully.

Outreach to schools, science centres, museums and the general public is very strong in the field of Gravitational Wave research, driven by interest in viewing the Universe through the medium of gravity - probing black holes, the warping of space-time and the big bang itself. We have successfully engaged the wider community through numerous efforts. For example we presented the exhibit "Can you hear Black Holes" at the 2008 Royal Society Summer exhibition with related exhibits still on show in the Science Museum in London, following which we undertook a key role in the design and construction of the NSF-funded US exhibit "Astronomy's New Messengers" which featured at the World Science Festivals in 2009 and 2010 and then as a touring exhibit. With funding from STFC we developed "Gravity Beyond the Apple", an interactive secondary school science show delivered in conjunction with the award-winning "Science Made Simple" public outreach company based in Cardiff University. We also made a key contribution to the "100 Hours of Astronomy" IYA2009 cornerstone project, which featured live webcasts from all the ground-based gravitational wave observatories, and more recently have been very active in Star-Gazing Live.

In the future we will maintain and extend our programme of public engagement, through our existing network of relationships with key outreach stakeholders, which includes: science centres and museums, national education authorities, the amateur astronomical community, the media and professional science communicators - particularly Wendy Sadler, director of "Science Made Simple" and the science team at the Glasgow Science Centre. Among our specific plans we will deliver across the UK numerous interactive lectures to schools, astronomical societies and the general public, in the areas of gravitational wave detection, cosmology and multi-messenger astronomy, drawing upon the suite of themed lectures which we have already developed.
 
Title Gravitational Wave Artwork Infinite LIGO Dreams 
Description Painting inspired by first detection of gravitational waves. 
Type Of Art Image 
Year Produced 2016 
Impact The Institute of Physics Scotland will be awarding 5 special edition prints 'Infinite LIGO Dreams' to winners of a science award that will be presented in the summer of 2017. Featured by Physics World http://blog.physicsworld.com/2016/11/24/the-beauty-of-gravitational-waves/ Featured by CERN Courier http://cerncourier.com/cws/download/Jan-Feb17 
 
Description First direct detection of gravitational waves and first ever observation of a binary black holes.
Exploitation Route A new era in observational astronomy
Sectors Education

 
Description Astroparticle Physics European Consortium
Geographic Reach Europe 
Policy Influence Type Participation in a advisory committee
 
Description KAGRA Programme Advisory Board
Geographic Reach Asia 
Policy Influence Type Participation in a advisory committee
 
Description LIGO Scientific Collaboration (LSC), Executive Committee
Geographic Reach Multiple continents/international 
Policy Influence Type Participation in a advisory committee
 
Description Member - ESA's Gravitational Observatory Advisory Team (GOAT)
Geographic Reach Multiple continents/international 
Policy Influence Type Participation in a advisory committee
 
Description SF - Member of STFC Computing Strategic Review
Geographic Reach National 
Policy Influence Type Participation in a advisory committee
URL http://www.stfc.ac.uk/about-us/how-we-are-governed/advisory-boards-panels-committees/computing-advis...
 
Description STFC Particle Astrophysics Advisory Panel
Geographic Reach National 
Policy Influence Type Participation in a advisory committee
 
Description Virgo Science & Technology Advisory Committee
Geographic Reach Europe 
Policy Influence Type Participation in a advisory committee
 
Description Advanced LIGO Operations Grant
Amount £901,107 (GBP)
Funding ID ST/I006285/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Public
Country United Kingdom
Start 08/2011 
End 07/2015
 
Description Indo-UK collaboration
Amount £7,580 (GBP)
Funding ID None 
Organisation The Royal Society 
Sector Charity/Non Profit
Country United Kingdom
Start 02/2013 
End 03/2013
 
Description Long Term Attachment
Amount £4,882 (GBP)
Funding ID ST/N504002/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Public
Country United Kingdom
Start 05/2016 
End 04/2019
 
Description Long Term Attachment
Amount £9,702 (GBP)
Funding ID ST/K501931/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Public
Country United Kingdom
Start 04/2014 
End 03/2017
 
Description Royal Society University Research Fellowship
Amount £803,198 (GBP)
Funding ID 516002.K5869/R OG 
Organisation The Royal Society 
Sector Charity/Non Profit
Country United Kingdom
Start 01/2007 
End 09/2014
 
Description STFC Advanced Fellowship
Amount £548,111 (GBP)
Funding ID ST/H008438/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Public
Country United Kingdom
Start 10/2010 
End 09/2015
 
Description ALUK 
Organisation University of Glasgow
Department UK Advanced LIGO Project (ALUK)
Country United Kingdom 
Sector Academic/University 
PI Contribution Enabling computational infrastructure for analysing data from Advanced LIGO.
Collaborator Contribution Data analysis on the computational infrastructure provided by us.
Impact Research papers on the analysis of data from LIGO detectors.
 
Description GEO600 
Organisation University of Glasgow
Department Physics and Astronomy Department
Country United Kingdom 
Sector Academic/University 
PI Contribution Detector characterisation and data analysis; strategic plans, scientific motivation for improving detector sensitivity.
Collaborator Contribution Building the detector, maintaining the detector, detector characterisation and data analysis.
Impact A working gravitational wave detector, development of advanced technology for advanced and third generation detectors.
 
Description LIGO Scientific Collaboration 
Organisation LIGO
Country United States 
Sector Academic/University 
PI Contribution Search algorithms and software, data analysis and astrophysical interpretation, scientific motivation for improvement in detector sensitivity
Collaborator Contribution Building and maintaining the LIGO detectors
Impact Publications, conference plenaries, conference contributions
 
Title Gravitational Wave Search Software 
Description Software to perform searches for gravitational waves associated with astrophysical triggers. 
Type Of Technology Software 
Year Produced 2010 
Open Source License? Yes  
Impact Used for many observational results publications by LIGO. 
URL https://trac.ligo.caltech.edu/xpipeline/
 
Title Gravitational Wave Search Software 
Description Software to perform searches for gravitational waves emitted by merging black holes and neutron stars. 
Type Of Technology Software 
Year Produced 2015 
Open Source License? Yes  
Impact This software was used in the detection of gravitational waves. 
URL https://github.com/ligo-cbc/pycbc
 
Description "Star Attractions at the Museum" at National Museum Cardiff 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Public talk on gravitational waves.
Year(s) Of Engagement Activity 2017
 
Description Al Jazeera TV coverage on the discovery of gravitational waves 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Live TV interview
Year(s) Of Engagement Activity 2016
URL https://www.youtube.com/watch?v=5v9a0DS9u8k
 
Description Ascoltare le voci dell'Universo (Listening the voices of the Universe) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Ascoltare le voci dell'Universo (Listening the voices of the Universe), a two-hour invited outreach talk on gravitational waves and their first detection given at the liceo scientifico statale Nomentano (Nomentano high school), Rome, Italy [01/06/2016]
Year(s) Of Engagement Activity 2016
 
Description BBC Science Cafe radio show about gravitational-wave discovery 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact 30-minute episode of the BBC Radio Science Cafe devoted to the announcement of the detection of GWs. Participants were Chris North and Patrick Sutton.
Year(s) Of Engagement Activity 2016
URL http://www.bbc.co.uk/programmes/b070nqz6
 
Description BBC Wales news item of gravitational-waves discovery 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact News items on the announcement of the first gravitational-wave detection, with interviews with faculty, research staff and students at Cardiff. This was the lead item on the evening news on BBC Wales on February 11, 2016.
Year(s) Of Engagement Activity 2016
 
Description BBC World Service programme: The Forum - The Rhythm 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact BBC World Service programme for 45 minutes
Year(s) Of Engagement Activity 2015
URL http://www.bbc.co.uk/programmes/p02jlyff
 
Description BBC World interview 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Interview with Mark Hannam on BBC World, on the significance of the GW detection. Audience estimated at over 110 million.
Year(s) Of Engagement Activity 2016
URL https://youtu.be/4bc6MkxH5sE
 
Description Black Hole Hunter 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact This is an on-line game that is on display at every major/minor outreach activity undertaken by members of the 1000-strong LIGO Scientific Collaboration.

It has been translated to German, French and Spain and attracts of 1000's of unique hits every year.
Year(s) Of Engagement Activity 2008
 
Description Black hole hunter 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Type Of Presentation Workshop Facilitator
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Developed the Black Hole Hunter game to give the public insight into how gravitational wave searches are performed. The game was updated at the time of the first gravitational wave detection. It has had over 50000 page views since the detectio, and 14000 unique visitors since the detection.


Tens of thousands of members of the public have played the game. It is widely used in outreach exhibits around the world and has been translated into French, Spanish and German
Year(s) Of Engagement Activity 2008,2009,2010,2011,2012,2013,2014,2015,2016,2017
URL http://blackholehunter.org/
 
Description Detailed follow-on Guardian interview on future prospects of the discovery 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Interview discussing the details about what can be expected next.
Year(s) Of Engagement Activity 2016
URL https://www.theguardian.com/science/2016/feb/12/gravitational-waves-what-breakthroughs-can-we-expect...
 
Description GW150914 - London Press Conference 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact A press release of the discovery of gravitational waves on Feb 11, 2016 at London
Year(s) Of Engagement Activity 2016
URL https://www.theguardian.com/science/2016/feb/11/gravitational-waves-discovery-hailed-as-breakthrough...
 
Description Gravitational Wave Discovery Video 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact A short podcast on the discovery of gravitational waves was made by Cardiff University and distributed via YouTube:
More than 12,000 views as of March 7 2016.
Year(s) Of Engagement Activity 2016
URL https://www.youtube.com/watch?v=Lcxt097G4Ps
 
Description Hay Festival, 30 June 2016, Hay-on-Wye, UK 
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 Talk on gravitational wave discovery at Hay Festival, 30 June 2016, Hay-on-Wye, UK.
Year(s) Of Engagement Activity 2016
 
Description Interview - LIGO detects whispers of another black-hole merger, Nature, 15 June 2016 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Quoted in Nature article.
Year(s) Of Engagement Activity 2016
 
Description Interview - The black-hole collision that reshaped physics, Nature, 23 March 2016 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Interview for Nature article.
Year(s) Of Engagement Activity 2016
 
Description LIGO-India announcement and coverage 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Report on the discovery and funding of LIGO India.
Year(s) Of Engagement Activity 2016
URL http://www.rappler.com/science-nature/earth-space/122854-india-gravitational-waves-cardiff
 
Description Physics World Interview on revised quadrupole formula 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact An interview on the publication of modified quadrupole formula and its relevance to gravitational waves
Year(s) Of Engagement Activity 2016
URL http://physicsworld.com/cws/article/news/2016/jan/21/are-gravitational-waves-being-redshifted-away-b...
 
Description Physics World interview 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Phone interview about the discovery
Year(s) Of Engagement Activity 2016
URL http://physicsworld.com/cws/article/news/2016/feb/17/indian-gravitational-wave-observatory-wins-gove...
 
Description Physics World interview on the discovery 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Physics World interview on the discovery of gravitational waves on the day of the press release.
Year(s) Of Engagement Activity 2016
URL http://physicsworld.com/cws/article/news/2016/feb/11/ligo-detects-first-ever-gravitational-waves-fro...
 
Description Physics World interview on the relevance of atom interferometry for GW detection 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact An interview by Physics World on the feasibility of cold atom interferometers as gravitational wave detectors
Year(s) Of Engagement Activity 2016
URL http://physicsworld.com/cws/article/news/2013/may/03/interfering-atoms-could-help-detect-gravitation...
 
Description Relativita, Festival Delle Scienze, 22 May 2016 Rome, Italy 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Participated in science festival.
Year(s) Of Engagement Activity 2016
 
Description Scienceface interview 
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 2017.09.22 Einstein's former summer house, Caputh, Germany: Interviewed on film for a new episode of the Scienceface series; film presently being edited for publication later in 2017.
Year(s) Of Engagement Activity 2016,2017
 
Description The First Ever Detection of Gravitational Waves 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Short video describing the first observation of gravitational waves. Posted on YouTube and viewed by over 10,000 people.
Year(s) Of Engagement Activity 2016
URL https://www.youtube.com/watch?v=Lcxt097G4Ps
 
Description The First Sounds of the Cosmic Symphony 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact The First Sounds of the Cosmic Symphony, a stand-up talk on gravitational-wave research activity for the general public, Chapter Arts Centre, Cardiff [14/10/2016]
Year(s) Of Engagement Activity 2016
 
Description The Guardian Newspaper interview 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Interview in the Guardian Newspaper about the discovery of gravitational waves
Year(s) Of Engagement Activity 2016
URL https://www.theguardian.com/science/2016/feb/11/gravitational-waves-discovery-hailed-as-breakthrough...
 
Description Video - LIGO: past, present and future 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact LIGO scientists at Cardiff talk about the historic first ever detection of gravitational waves. Looking to the future, they speak about the prospect of a new era of "gravitational wave astronomy". Viewed by more than 1200 people to date.
Year(s) Of Engagement Activity 2016
URL https://www.youtube.com/watch?v=TNhI57b9JOc