Improved Analysis of GW150914 Using a Fully Spin-Precessing Waveform Model

Abstract

This paper presents updated estimates of source parameters for GW150914, a binary black-hole coalescence event detected by the Laser Interferometer Gravitational-wave Observatory (LIGO) in 2015 [Abbott et al. Phys. Rev. Lett. 116, 061102 (2016).]. Abbott et al. [Phys. Rev. Lett. 116, 241102 (2016).] presented parameter estimation of the source using a 13-dimensional, phenomenological precessing-spin model (precessing IMRPhenom) and an 11-dimensional nonprecessing effective-onebody (EOB) model calibrated to numerical-relativity simulations, which forces spin alignment (nonprecessing EOBNR). Here, we present new results that include a 15-dimensional precessingspin waveform model (precessing EOBNR) developed within the EOB formalism. We find good agreement with the parameters estimated previously [Abbott et al. Phys. Rev. Lett. 116, 241102 (2016).], and we quote updated component masses of 35 þ5 −3 M ⊙ and 30 þ3 −4 M ⊙ (where errors correspond to 90% symmetric credible intervals). We also present slightly tighter constraints on the dimensionless spin magnitudes of the two black holes, with a primary spin estimate < 0.65 and a secondary spin estimate < 0.75 at 90% probability. Abbott et al. [Phys. Rev. Lett. 116, 241102 (2016).] estimated the systematic parameter-extraction errors due to waveform-model uncertainty by combining the posterior probability densities of precessing IMRPhenom and nonprecessing EOBNR. Here, we find that the two precessing-spin models are in closer agreement, suggesting that these systematic errors are smaller than previously quoted.

Binary Black Hole Mergers in the First Advanced LIGO Observing Run

“…V. Full results for GW150914 have been provided in Refs. [39,40], and key results for LVT151012 have been given in Ref. [44].…”

“…An analysis using a fully precessing EOBNR waveform [219], as done in Ref. [40], will be reported in the future; this analysis is currently too computationally expensive for results to be presented now.…”

“…The parameters of GW150914 have been reported previously in Refs. [39,40]. We provide revised results which make use of updated instrumental calibration.…”

Waveform model for an eccentric binary black hole based on the effective-one-body-numerical-relativity formalism

“…As firstly done by Pan and his coworkers in [7], such combination gives effective-one-body numerical relativity (EOBNR) model. Currently the most advanced EOBNR model is the SEOBNR which includes version 1 [51], version 2 [5] and version 3 [3,52,53]. SEOBNR is valid only for quasi-circular orbit and black hole spin perpendicular to the orbital plane which means the precession is not presented.…”

LIGO and the opening of a unique observational window on the universe

“…A Bayesian framework is used with two different sampling methods using many different waveform models calibrated against general relativity (GR); convergence and consistent posterior probability distributions for many parameters are required (35,36). In the case of the first detection (GW150914), the signal-to-noise ratio is high enough, so that the main mass parameter (chirp mass) of the source can be extracted using a collection of generic wavelets, without having to use coalescence templates.…”