- Open Access
Improved Analysis of GW150914 Using a Fully Spin-Precessing Waveform Model
Phys. Rev. X 6, 041014 – Published 21 October, 2016
DOI: https://doi.org/10.1103/PhysRevX.6.041014
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-one-body (EOB) model calibrated to numerical-relativity simulations, which forces spin alignment (nonprecessing EOBNR). Here, we present new results that include a 15-dimensional precessing-spin 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 and (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 and a secondary spin estimate 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.
Physics Subject Headings (PhySH)
Popular Summary
On September 14, 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected a binary black hole coalescence event, GW150914.
Spin is known to be intrinsic to stellar-mass black holes, and previous work presented parameter estimation of the source using a 13-dimensional, phenomenological model with precessing spin (i.e., the spins of the individual black holes are not assumed to be aligned with the orbital angular momentum of the binary; “precessing IMRPhenom”) and an 11-dimensional nonprecessing effective-one-body model calibrated to numerical-relativity simulations, which forces spin alignment (“nonprecessing EOBNR”). Here, we share new results that include a 15-dimensional precessing-spin waveform model developed within the effective one-body formalism. This model takes into account the 6 degrees of freedom associated with black hole spin.
We recover good agreement with the parameters estimated previously, and we quote updated black hole component masses of roughly 35 and 30 times the mass of the Sun. We also present slightly tighter constraints on the dimensionless spin magnitudes of the two black holes: a primary spin estimate of 0.65 and a secondary spin estimate of 0.75, where a value of 0.0 indicates no spin rotation and a value of 1.0 indicates maximal rotation. Previous work 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.
We expect that our findings will pave the way for more precise estimates of black hole parameters recovered during Advanced LIGO’s second observing run, which is slated to commence in 2016. In particular, our results will be most applicable to black hole pairs with a larger mass asymmetry than the GW150914 system discovered in 2015.
See Also
Binary Black Hole Mergers in the First Advanced LIGO Observing Run
Article Text
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