93 research outputs found
Accuracy of binary black hole waveform models for aligned-spin binaries
Coalescing binary black holes are among the primary science targets for
second generation ground-based gravitational wave (GW) detectors. Reliable GW
models are central to detection of such systems and subsequent parameter
estimation. This paper performs a comprehensive analysis of the accuracy of
recent waveform models for binary black holes with aligned spins, utilizing a
new set of high-accuracy numerical relativity simulations. Our analysis
covers comparable mass binaries (), and samples
independently both black hole spins up to dimensionless spin-magnitude of
for equal-mass binaries and for unequal mass binaries. Furthermore, we
focus on the high-mass regime (total mass ). The two most
recent waveform models considered (PhenomD and SEOBNRv2) both perform very well
for signal detection, losing less than 0.5\% of the recoverable signal-to-noise
ratio , except that SEOBNRv2's efficiency drops mildly for both black
hole spins aligned with large magnitude. For parameter estimation, modeling
inaccuracies of SEOBNRv2 are found to be smaller than systematic uncertainties
for moderately strong GW events up to roughly . PhenomD's
modeling errors are found to be smaller than SEOBNRv2's, and are generally
irrelevant for . Both models' accuracy deteriorates with
increased mass-ratio, and when at least one black hole spin is large and
aligned. The SEOBNRv2 model shows a pronounced disagreement with the numerical
relativity simulation in the merger phase, for unequal masses and
simultaneously both black hole spins very large and aligned. Two older waveform
models (PhenomC and SEOBNRv1) are found to be distinctly less accurate than the
more recent PhenomD and SEOBNRv2 models. Finally, we quantify the bias expected
from all GW models during parameter estimation for recovery of binary's masses
and spins.Comment: 24 pages, 15 figures, minor change
Periastron Advance in Spinning Black Hole Binaries: Gravitational Self-Force from Numerical Relativity
We study the general relativistic periastron advance in spinning black hole
binaries on quasi-circular orbits, with spins aligned or anti-aligned with the
orbital angular momentum, using numerical-relativity simulations, the
post-Newtonian approximation, and black hole perturbation theory. By imposing a
symmetry by exchange of the bodies' labels, we devise an improved version of
the perturbative result, and use it as the leading term of a new type of
expansion in powers of the symmetric mass ratio. This allows us to measure, for
the first time, the gravitational self-force effect on the periastron advance
of a non-spinning particle orbiting a Kerr black hole of mass M and spin S =
-0.5 M^2, down to separations of order 9M. Comparing the predictions of our
improved perturbative expansion with the exact results from numerical
simulations of equal-mass and equal-spin binaries, we find a remarkable
agreement over a wide range of spins and orbital separations.Comment: 18 pages, 12 figures; matches version to appear in Phys. Rev.
Modeling the source of GW150914 with targeted numerical-relativity simulations
In fall of 2015, the two LIGO detectors measured the gravitational wave
signal GW150914, which originated from a pair of merging black holes. In the
final 0.2 seconds (about 8 gravitational-wave cycles) before the amplitude
reached its maximum, the observed signal swept up in amplitude and frequency,
from 35 Hz to 150 Hz. The theoretical gravitational-wave signal for merging
black holes, as predicted by general relativity, can be computed only by full
numerical relativity, because analytic approximations fail near the time of
merger. Moreover, the nearly-equal masses, moderate spins, and small number of
orbits of GW150914 are especially straightforward and efficient to simulate
with modern numerical-relativity codes. In this paper, we report the modeling
of GW150914 with numerical-relativity simulations, using black-hole masses and
spins consistent with those inferred from LIGO's measurement. In particular, we
employ two independent numerical-relativity codes that use completely different
analytical and numerical methods to model the same merging black holes and to
compute the emitted gravitational waveform; we find excellent agreement between
the waveforms produced by the two independent codes. These results demonstrate
the validity, impact, and potential of current and future studies using
rapid-response, targeted numerical-relativity simulations for better
understanding gravitational-wave observations.Comment: 11 pages, 3 figures, submitted to Classical and Quantum Gravit
Impact of subdominant modes on the interpretation of gravitational-wave signals from heavy binary black hole systems
Over the past year, a handful of new gravitational wave models have been developed to include multiple harmonic modes thereby enabling for the first time fully Bayesian inference studies including higher modes to be performed. Using one recently developed numerical relativity surrogate model, NRHybSur3dq8, we investigate the importance of higher modes on parameter inference of coalescing massive binary black holes. We focus on examples relevant to the current three-detector network of observatories, with a detector-frame mass set to
120 M⊙ and with signal amplitude values that are consistent with plausible candidates for the next few observing runs. We show that for such systems the higher mode content will be important for interpreting coalescing binary black holes, reducing systematic bias, and computing properties of the remnant object. Even for comparable-mass binaries and at low signal amplitude, the omission of higher modes can influence posterior probability distributions. We discuss the impact of our results on source population inference and self-consistency tests of general relativity. Our work can be used to better understand asymmetric binary black hole merger events, such as GW190412. Higher modes are critical for such systems, and their omission usually produces substantial parameter biases
Complete waveform model for compact binaries on eccentric orbits
We present a time domain waveform model that describes the inspiral, merger and ringdown of compact binary systems whose components are nonspinning, and which evolve on orbits with low to moderate eccentricity. The inspiral evolution is described using third-order post-Newtonian equations both for the equations of motion of the binary, and its far-zone radiation field. This latter component also includes instantaneous, tails and tails-of-tails contributions, and a contribution due to nonlinear memory. This framework reduces to the post-Newtonian approximant TaylorT4 at third post-Newtonian order in the zero-eccentricity limit. To improve phase accuracy, we also incorporate higher-order post-Newtonian corrections for the energy flux of quasicircular binaries and gravitational self-force corrections to the binding energy of compact binaries. This enhanced prescription for the inspiral evolution is combined with a fully analytical prescription for the merger-ringdown evolution constructed using a catalog of numerical relativity simulations. We show that this inspiral-merger-ringdown waveform model reproduces the effective-one-body model of Ref. [Y. Pan et al., Phys. Rev. D 89, 061501 (2014).] for quasicircular black hole binaries with mass ratios between 1 to 15 in the zero-eccentricity limit over a wide range of the parameter space under consideration. Using a set of eccentric numerical relativity simulations, not used during calibration, we show that our new eccentric model reproduces the true features of eccentric compact binary coalescence throughout merger. We use this model to show that the gravitational-wave transients GW150914 and GW151226 can be effectively recovered with template banks of quasicircular, spin-aligned waveforms if the eccentricity e_0 of these systems when they enter the a LIGO band at a gravitational-wave frequency of 14 Hz satisfies e^(GW150914)_0 ≤ 0.15 and e^(GW151226) _0 ≤ 0.1. We also find that varying the spin combinations of the quasicircular, spin-aligned template waveforms does not improve the recovery of nonspinning, eccentric signals when e_0 ≥ 0.1. This suggests that these two signal manifolds are predominantly orthogonal
Detection and characterization of spin-orbit resonances in the advanced gravitational wave detectors era
In this paper, we test the performance of templates in detection and
characterization of Spin-orbit resonant (SOR) binaries. We use precessing
SEOBNRv3 waveforms as well as {\it four} numerical relativity (NR) waveforms to
model GWs from SOR binaries and filter them through IMRPhenomD, SEOBNRv4
(non-precessing) and IMRPhenomPv2 (precessing) approximants. We find that
IMRPhenomD and SEOBNRv4 recover only of injections with fitting
factor (FF) higher than 0.97 (or 90\% of injections with ).However, using the sky-maxed statistic, IMRPhenomPv2 performs
magnificently better than their non-precessing counterparts with recovering
of the injections with FFs higher than 0.97. Interestingly, injections
with have higher FFs ( is the angle
between the components of the black hole spins in the plane orthogonal to the
orbital angular momentum) as compared to their and
generic counterparts. This implies that we will have a slight observation bias
towards SORs while using non-precessing templates for
searches. All template approximants are able to recover most of the injected NR
waveforms with FFs . For all the injections including NR, the error in
estimating chirp mass remains below with minimum error for resonant binaries. The symmetric mass ratio can be estimated
with errors below . The effective spin parameter is
measured with maximum absolute error of 0.13. The in-plane spin parameter
is mostly underestimated indicating that a precessing signal will be
recovered as a relatively less precessing signal. Based on our findings, we
conclude that we not only need improvements in waveform models towards
precession and non-quadrupole modes but also better search strategies for
precessing GW signals.Comment: 27 pages, 15 figures. Abstract shortened due to word limi
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