Journal article

Search for gravitational waves from five low mass x-ray binaries in the second Advanced LIGO observing run with an improved hidden Markov model

Hannah Middleton, Patrick Clearwater, Andrew Melatos, Liam Dunn

Physical Review D: Particles, Fields, Gravitation and Cosmology | American Physical Society | Published : 2020


Low mass x-ray binaries are prime targets for continuous gravitational wave searches by ground-based interferometers. Results are presented from a search for five low-mass x-ray binaries whose spin frequencies and orbital elements are measured accurately from x-ray pulsations: HETE J1900.1-2455, IGR J 00291+5934, SAX J1808.4-3658, XTE J0929-314, and XTE J1814-338. Data are analysed from Observing Run 2 of the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO). The search algorithm uses a hidden Markov model to track spin wandering, the J -statistic maximum likelihood matched filter to track orbital phase, and a suite of five vetoes to reject artefacts from non-Gaussian noise..

View full abstract


Awarded by Australian Research Council Centre of Excellence for Gravitational Wave Discovery (OzGrav)

Funding Acknowledgements

The authors are grateful to Sofia Suvorova, William Moran, and Robin Evans for their past developmental work on HMMs for continuous wave searches and also to them and Margaret Millhouse, Patrick Meyers, and Julian Carlin for helpful discussions including advice on the off-target threshold and veto procedure; Shanika Galaudage and Duncan Galloway for advice on selecting LMXB targets and locating the most accurate EM measurements of the targets' parameters in the literature; and Ling Sun for helpful comments on the manuscript. We also thank the Continuous Wave Working Group of the LIGO Scientific Collaboration and Virgo Collaboration for their useful discussion. This research is supported by the Australian Research Council Centre of Excellence for Gravitational Wave Discovery (OzGrav) (Project No. CE170100004). This work used computational resources of the OzSTAR national facility at Swinburne University of Technology and also at the California Institute of Technology. OzSTAR is funded by Swinburne University of Technology and the National Collaborative Research Infrastructure Strategy (NCRIS). This research has made use of data, software and/or web tools obtained from the Gravitational Wave Open Science Center (, a service of LIGO Laboratory, the LIGO Scientific Collaboration and the Virgo Collaboration. LIGO is funded by the U.S. National Science Foundation. Virgo is funded by the French Centre National de Recherche Scientifique (CNRS), the Italian Istituto Nazionale della Fisica Nucleare (INFN) and the Dutch Nikhef, with contributions by Polish and Hungarian institutes. This work has been assigned LIGO document number P1900273.