Journal article

Hidden Markov model tracking of continuous gravitational waves from a neutron star with wandering spin

S Suvorova, L Sun, A Melatos, W Moran, RJ Evans

Physical Review D | AMER PHYSICAL SOC | Published : 2016

Abstract

Gravitational wave searches for continuous-wave signals from neutron stars are especially challenging when the star's spin frequency is unknown a priori from electromagnetic observations and wanders stochastically under the action of internal (e.g., superfluid or magnetospheric) or external (e.g., accretion) torques. It is shown that frequency tracking by hidden Markov model (HMM) methods can be combined with existing maximum likelihood coherent matched filters like the F-statistic to surmount some of the challenges raised by spin wandering. Specifically, it is found that, for an isolated, biaxial rotor whose spin frequency walks randomly, HMM tracking of the F-statistic output from coherent..

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Grants

Awarded by Australian Research Council


Funding Acknowledgements

We would like to thank Paul Lasky, Chris Messenger, Keith Riles, Karl Wette, Letizia Sammut, John Whelan, and the LIGO Scientific Collaboration Continuous Wave Working Group for detailed comments and informative discussions. The synthetic data for stage I of the Sco X-1 MDC were prepared primarily by Chris Messenger with the assistance of members of the MDC team [54]. We thank Chris Messenger and Paul Lasky for their assistance in handling the MDC data. L. Sun is supported by an Australian Postgraduate Award. The research was supported by Australian Research Council (ARC) Discovery Project No. DP110103347.