Evidence-based search method for gravitational waves from neutron star ring-downs

Clark, James and Heng, Ik Siong and Pitkin, Matthew and Woan, Graham (2007) Evidence-based search method for gravitational waves from neutron star ring-downs. Physical Review D, 76 (4). ISSN 1550-7998

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Abstract

The excitation of quadrupolar quasinormal modes in a neutron star leads to the emission of a short, distinctive, burst of gravitational radiation in the form of a decaying sinusoid or “ring-down.” We present a Bayesian analysis method which incorporates relevant prior information about the source and known instrumental artifacts to conduct a robust search for the gravitational wave emission associated with pulsar glitches and soft γ-ray repeater flares. Instrumental transients are modeled as sine-Gaussian and their evidence, or marginal likelihood, is compared with that of Gaussian white noise and ring-downs via the “odds-ratio.” Tests using simulated data with a noise spectral density similar to the LIGO interferometer around 1 kHz yield 50% detection efficiency and 1% false alarm probability for ring-down signals with signal-to-noise ratio ρ=5.2. For a source at 15 kpc this requires an energy of 1.3 × 10−5 M⊙c2 to be emitted as gravitational waves.