Testing general relativity with compact coalescing binaries: comparing exact and predictive methods to compute the Bayes factor
Abstract
The second generation of gravitationalwave detectors is scheduled to start operations in 2015. Gravitationalwave signatures of compact binary coalescences could be used to accurately test the strongfield dynamical predictions of general relativity (GR). Computationally expensive data analysis pipelines, including TIGER (test infrastructure for general relativity), have been developed to carry out such tests. As a means to cheaply assess whether a particular deviation from GR can be detected, Cornish et al (2011 Phys. Rev. D 84 062003) and Vallisneri (2012 Phys. Rev. D 86 082001) recently proposed an approximate scheme to compute the Bayes factor between a GR gravitationalwave model and a model representing a class of alternative theories of gravity parametrized by one additional parameter. This approximate scheme is based on only two easytocompute quantities: the signaltonoise ratio (SNR) of the signal and the fitting factor (FF) between the signal and the manifold of possible waveforms within GR. In this work, we compare the prediction from the approximate formula against an exact numerical calculation of the Bayes factor using the lalinference library. We find that, using frequencydomain waveforms, the approximate scheme predicts exact results with good accuracy, providing the correct scaling with the SNR at a FF value of 0.992 and the correct scaling with the FF at a SNR of 20, down to a FF of ∼ 0.9. We extend the framework for the approximate calculation of the Bayes factor, which significantly increases its range of validity, at least to FFs of ∼ 0.7 or higher.
 Publication:

Classical and Quantum Gravity
 Pub Date:
 October 2014
 DOI:
 10.1088/02649381/31/20/205006
 arXiv:
 arXiv:1408.2356
 Bibcode:
 2014CQGra..31t5006D
 Keywords:

 General Relativity and Quantum Cosmology
 EPrint:
 13 pages, 4 figures, accepted for publication in Classical and Quantum Gravity