Parameter Estimation for Binary Neutron-star Coalescences with Realistic Noise during the Advanced LIGO Era
Advanced ground-based gravitational-wave (GW) detectors begin operation imminently. Their intended goal is not only to make the first direct detection of GWs, but also to make inferences about the source systems. Binary neutron-star mergers are among the most promising sources. We investigate the performance of the parameter-estimation (PE) pipeline that will be used during the first observing run of the Advanced Laser Interferometer Gravitational-wave Observatory (aLIGO) in 2015: we concentrate on the ability to reconstruct the source location on the sky, but also consider the ability to measure masses and the distance. Accurate, rapid sky localization is necessary to alert electromagnetic (EM) observatories so that they can perform follow-up searches for counterpart transient events. We consider PE accuracy in the presence of non-stationary, non-Gaussian noise. We find that the character of the noise makes negligible difference to the PE performance at a given signal-to-noise ratio. The source luminosity distance can only be poorly constrained, since the median 90% (50%) credible interval scaled with respect to the true distance is 0.85 (0.38). However, the chirp mass is well measured. Our chirp-mass estimates are subject to systematic error because we used gravitational-waveform templates without component spin to carry out inference on signals with moderate spins, but the total error is typically less than 10^(-3) M_☉. The median 90% (50%) credible region for sky localization is ~ 600 deg^2 (~150 deg^2), with 3% (30%) of detected events localized within 100 deg^2. Early aLIGO, with only two detectors, will have a sky-localization accuracy for binary neutron stars of hundreds of square degrees; this makes EM follow-up challenging, but not impossible.
© 2015 American Astronomical Society. Received 2014 November 25; accepted 2015 February 23; published 2015 May 11. This work was supported by the Science and Technology Facilities Council. P.B.G. acknowledges NASA grant NNX12AN10G. S.V. acknowledges the support of the National Science Foundation and the LIGO Laboratory. J.V. was supported by STFC grant ST/K005014/1. LIGO was constructed by the California Institute of Technology and Massachusetts Institute of Technology with funding from the National Science Foundation and operates under cooperative agreement PHY-0757058. Results were produced using the computing facilities of the LIGO DataGrid including: the Nemo computing cluster at the Center for Gravitation and Cosmology at the University of Wisconsin–Milwauke under NSF Grants PHY-0923409 and PHY-0600953; the Atlas computing cluster at the Albert Einstein Institute, Hannover; the LIGO computing clusters at Caltech, and the facilities of the Advanced Research Computing @ Cardiff (ARCCA) Cluster at Cardiff University. We are especially grateful to Paul Hopkins of ARCCA for assistance. Some results were produced using the post-processing tools of the plotutils library at http://github.com/farr/plotutils, and some were derived using HEALPix (Gorski et al. 2005). This paper is has been assigned LIGO document reference LIGO-P1400232. It contains some results originally included in LIGO technical report LIGO-T1400480.
Published - 0004-637X_804_2_114.pdf
Submitted - 1411.6934v2.pdf