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  • Review Article
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Astrophysics with continuous gravitational waves

Nature Astronomy volume 7, pages 1160–1170 (2023)Cite this article

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Abstract

Direct detection of gravitational waves has become a powerful new tool of multi-messenger astrophysics. Apart from short-duration (transient) events, such as the inspirals and mergers of stellar-mass compact objects, we envisage other signal types of much longer duration—continuous gravitational waves. Traditionally associated with neutron star astrophysics, and hence with their largely unknown dense-matter interiors, continuous gravitational waves are now also entering other fields of astrophysics, namely, searches for dark matter, primordial black holes or exotic particles. Their long duration allows for qualitatively new possibilities, such as reproducible studies and tests of gravitational theory. This Review summarizes the results obtained in the recent O3 observing run of the LIGO–Virgo–KAGRA collaboration, the current status of the data analysis and the theoretical ideas related to astrophysical models. We show that O3 observations have started probing astrophysically relevant scenarios, and discuss how the improved sensitivity of the currently ongoing O4 observing run may offer a real possibility for a first detection of continuous gravitational waves.

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Fig. 1: Ellipticity as a function of the GW frequency for a selection of pulsars.
Fig. 2: Current upper limits obtained from the O3 all-sky search.
Fig. 3: Constraints on the mass of PSR J0537−6910.
Fig. 4: Constraints on the mass of the NS in Scorpius X-1.
Fig. 5: Boson mass as a function of the BH mass.

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Data availability

All data underlying the figures presented in this Review are available together with the original referenced publications at https://dcc.ligo.org/cgi-bin/DocDB/DocumentDatabase. Furthermore, the full O3 datasets underlying the analysis can be found at https://gwosc.org/data/. Any additional data will be made available by the corresponding author upon request.

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Acknowledgements

This material is based on work supported by NSF’s LIGO Laboratory which is a major facility fully funded by the National Science Foundation. We gratefully acknowledge the support of the Science and Technology Facilities Council (STFC) of the United Kingdom, the Max-Planck Society (MPS), and the State of Niedersachsen/Germany for support of the construction of Advanced LIGO and construction and operation of the GEO 600 detector. Additional support for Advanced LIGO was provided by the Australian Research Council. We gratefully acknowledge the Italian Istituto Nazionale di Fisica Nucleare (INFN), the French Centre National de la Recherche Scientifique (CNRS) and the Netherlands Organization for Scientific Research (NWO), for the construction and operation of the Virgo detector and the creation and support of the EGO consortium. We gratefully acknowledge research support from these agencies as well as by the Council of Scientific and Industrial Research of India, the Department of Science and Technology, India, the Science and Engineering Research Board (SERB), India, the Ministry of Human Resource Development, India, the Spanish Agencia Estatal de Investigacion (AEI), the Spanish Ministerio de Ciencia e Innovacion and Ministerio de Universidades, the Conselleria de Fons Europeus, Universitat i Cultura and the Direccio General de Política Universitaria i Recerca del Govern de les Illes Balears, the Conselleria d’Innovacio, Universitats, Cíencia i Societat Digital de la Generalitat Valenciana and the CERCA Programme Generalitat de Catalunya, Spain, the National Science Centre of Poland and the European Union - European Regional Development Fund; Foundation for Polish Science (FNP), the Swiss National Science Foundation (SNSF), the Russian Foundation for Basic Research, the Russian Science Foundation, the European Commission, the European Social Funds (ESF), the European Regional Development Funds (ERDF), the Royal Society, the Scottish Funding Council, the Scottish Universities Physics Alliance, the Hungarian Scientific Research Fund (OTKA), the French Lyon Institute of Origins (LIO), the Belgian Fonds de la Recherche Scientifique (FRS-FNRS), Actions de Recherche Concertees (ARC) and Fonds Wetenschappelijk Onderzoek - Vlaanderen (FWO), Belgium, the Paris Île-de-France Region, the National Research, Development and Innovation Office Hungary (NKFIH), the National Research Foundation of Korea, the Natural Science and Engineering Research Council Canada, Canadian Foundation for Innovation (CFI), the Brazilian Ministry of Science, Technology, and Innovations, the International Center for Theoretical Physics South American Institute for Fundamental Research (ICTP-SAIFR), the Research Grants Council of Hong Kong, the National Natural Science Foundation of China (NSFC), the Leverhulme Trust, the Research Corporation, the National Science and Technology Council (NSTC), Taiwan, the United States Department of Energy, and the Kavli Foundation. We gratefully acknowledge the support of the NSF, STFC, INFN and CNRS for provision of computational resources. This work was supported by MEXT, JSPS Leading-edge Research Infrastructure Program, JSPS Grant-in-Aid for Specially Promoted Research 26000005, JSPS Grant-in-Aid for Scientific Research on Innovative Areas 2905: JP17H06358, JP17H06361 and JP17H06364, JSPS Core-to-Core Program A. Advanced Research Networks, JSPS Grant-in-Aid for Scientific Research (S) 17H06133 and 20H05639, JSPS Grant-in-Aid for Transformative Research Areas (A) 20A203: JP20H05854, the joint research programme of the Institute for Cosmic Ray Research, University of Tokyo, National Research Foundation (NRF), Computing Infrastructure Project of Global Science experimental Data hub Center (GSDC) at KISTI, Korea Astronomy and Space Science Institute (KASI), and Ministry of Science and ICT (MSIT) in Korea, Academia Sinica (AS), AS Grid Center (ASGC) and the National Science and Technology Council (NSTC) in Taiwan under grants including the Rising Star Program and Science Vanguard Research Program, Advanced Technology Center (ATC) of NAOJ, and Mechanical Engineering Center of KEK. This work was partially supported by the Polish National Science Centre grant nos 2017/26/M/ST9/00978, 2018/29/B/ST9/02013 and 2021/43/B/ST9/01714.

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  1. Nicolaus Copernicus Astronomical Center of the Polish Academy of Sciences, Warsaw, Poland

    B. Haskell & M. Bejger

  2. INFN, Ferrara, Italy

    M. Bejger

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  1. B. Haskell
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  2. M. Bejger
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B.H. and M.B. contributed to the planning, interpretation of the results and writing of the paper.

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Correspondence to B. Haskell.

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Haskell, B., Bejger, M. Astrophysics with continuous gravitational waves. Nat Astron 7, 1160–1170 (2023). https://doi.org/10.1038/s41550-023-02059-w

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