The first informative astrophysical calibration of gravitational-wave detectors is reported using GW240925 and GW250207.
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GWTC-4.0: Tests of General Relativity. II. Parameterized Tests
Canonical reference. 88% of citing Pith papers cite this work as background.
abstract
In this second of three papers on tests of general relativity (GR) applied to the compact binary coalescence signals in the fourth Gravitational-Wave Transient Catalog (GWTC-4.0), we present the results of the parameterized tests of GR and constraints on line-of-sight acceleration. We include events up to and including the first part of the fourth observing run (O4a) of the LIGO Virgo KAGRA detectors. As in the other two papers in this series, we restrict our analysis to the 42 confident signals, measured by at least two detectors, that have false alarm rates $\le 10^{-3} \mathrm{yr}^{-1}$ from O4a, in addition to the 49 such events from previous observing runs. This paper focuses on the eight tests that constrain parameterized deviations from the expected GR (or unaccelerated) values. These include modifications of post-Newtonian (PN) parameters, spin-induced quadrupole moments different from those of a binary black hole, and possible dispersive or birefringent propagation effects. Overall, we find no evidence for physics beyond GR, for spin-induced quadrupole moments different from those of a Kerr black hole in GR, or for line of sight acceleration, with more than 90% of the events including the null result (no deviation) within their 90% credible intervals. We discuss possible systematics affecting the other events and tests, even though they are statistically not surprising, given noise. We improve the bounds on deviations from the GR PN coefficients by factors of 1.2-5.5 and provide illustrative translations to constraints on some modified theories. Also, we update the bound on the mass of the graviton, at 90% credibility, to $m_g \leq 1.92\times 10^{-23} \mathrm{eV}/c^2$. Thus, we see that GR holds, and many of the bounds on possible deviations derived from our events are the best to date.
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2026 20representative citing papers
Numerical relativity simulations of black hole scattering in Einstein-scalar-Gauss-Bonnet gravity agree closely with effective-one-body analytic predictions.
GW241011 data shows consistency with Kerr black holes for both quadrupole and octupole moments and delivers the first observational bounds on spin-induced octupole deviations.
Multiband observations of eccentric binary black holes can constrain dipole-radiation deviations from general relativity to |b| ≲ 10^{-7} for a GW231123-like event when combining one year of space-based data with ground-informed priors.
Numerical simulations of equal-mass boson-star mergers reveal larger waveform deviations from black-hole binaries in late inspiral and merger, plus odd multipole excitations for certain scalar-field phases, with some signals degenerate until IMR consistency tests are applied.
Landau coefficients for scalarization phase transitions are calculated from first principles via reduction of the theory's energy functional to an effective energy function.
Polynomial models for the (2,2) post-merger waveform amplitudes of eccentric non-spinning binary black holes are constructed from numerical-relativity data as functions of symmetric mass ratio and two merger-time dynamical parameters.
Leading-order deviations from general relativity in scalar quasinormal modes of rotating black holes are computed numerically up to dimensionless spins of 0.99 in quadratic-curvature scalar-tensor theories.
Numerical simulations of collapsing scalarized neutron stars show scalar radiation energy of order 10^{-3} solar masses, orders of magnitude above the tensor quadrupolar emission, potentially observable to test modified gravity.
Bayesian analysis finds individual QNM frequencies near avoided crossings hard to resolve even under optimistic conditions, though collective AC waveform signatures may remain detectable if those modes dominate and slower-mode contamination is minimal.
Leading-order cubic-curvature corrections to scalar quasinormal modes of black holes with spins up to 0.99M are computed numerically for modes up to l=5 with relative errors below 10^{-4}.
Unmodeled point-mass lensing produces a spurious nonzero graviton mass posterior in GW231123 that vanishes when lensing is included in the analysis.
Using TaylorF2 post-Newtonian waveforms truncated at ISCO, the study finds that Einstein Telescope and Cosmic Explorer can reach SNR of 100-350 and measure primary spin to 10^{-4}-10^{-3} precision for 0.1-2 solar mass exotic compact objects.
Spin prior choices propagate into tests of GR via the 1.5PN deviation parameter δφ̂3 in a non-trivial, event-dependent way, with stronger effects for short-inspiral events and partial degeneracy with χ_eff when the deviation is included.
Orthonormal QNM analysis of GW250114 raises the significance of the first overtone of the ℓ=m=2 mode from 82.5% to 99.9% and detects no significant deviation from Kerr predictions.
Exact Hawking area law from black hole mergers restricts quantum gravity to singular Ricci-flat or specific regular black holes in Stelle and nonlocal theories, derives the standard entropy-area law, and realizes Barrow fractal black holes.
The prompt response is ~1.2 times stronger than quasinormal mode excitation during inspiral and enables 99% accurate reconstruction of the full inspiral-merger-ringdown waveform when combined with other components.
Bayesian analysis of GW170817 with PPE framework and EM polarization constraints shows mild preference for scalar mode in quadrupole harmonics and improves bounds on non-GR parameters by up to 60%.
Reanalysis of flagged LVK events with waveform uncertainty models produces consistent spin and precession inferences across raw/deglitched data and multiple waveform approximants.
Bayesian constraints from GWTC-4 binary black hole inspirals show Johannsen metric deformation parameters α13 and ε3 consistent with zero, supporting the Kerr hypothesis.
citing papers explorer
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GW240925 and GW250207: Astrophysical Calibration of Gravitational-wave Detectors
The first informative astrophysical calibration of gravitational-wave detectors is reported using GW240925 and GW250207.
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Black-Hole Scattering in Einstein-scalar-Gauss-Bonnet: Numerical Relativity Meets Analytics
Numerical relativity simulations of black hole scattering in Einstein-scalar-Gauss-Bonnet gravity agree closely with effective-one-body analytic predictions.
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Testing the Kerr hypothesis beyond the quadrupole with GW241011
GW241011 data shows consistency with Kerr black holes for both quadrupole and octupole moments and delivers the first observational bounds on spin-induced octupole deviations.
-
Constraining Dipole Radiation with Multiband Gravitational Waves from Eccentric Binary Black Holes
Multiband observations of eccentric binary black holes can constrain dipole-radiation deviations from general relativity to |b| ≲ 10^{-7} for a GW231123-like event when combining one year of space-based data with ground-informed priors.
-
Lessons from binary dynamics of inspiralling equal-mass boson-star mergers
Numerical simulations of equal-mass boson-star mergers reveal larger waveform deviations from black-hole binaries in late inspiral and merger, plus odd multipole excitations for certain scalar-field phases, with some signals degenerate until IMR consistency tests are applied.
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Underlying mechanisms of phase transitions in scalar-tensor theories
Landau coefficients for scalarization phase transitions are calculated from first principles via reduction of the theory's energy functional to an effective energy function.
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Highly eccentric non-spinning binary black hole mergers: quadrupolar post-merger waveforms
Polynomial models for the (2,2) post-merger waveform amplitudes of eccentric non-spinning binary black holes are constructed from numerical-relativity data as functions of symmetric mass ratio and two merger-time dynamical parameters.
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Quadratic gravity corrections to scalar QNMs of rapidly rotating black holes
Leading-order deviations from general relativity in scalar quasinormal modes of rotating black holes are computed numerically up to dimensionless spins of 0.99 in quadratic-curvature scalar-tensor theories.
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Rapidly Rotating Neutron Star Collapse in Massive Scalar-Tensor Theories
Numerical simulations of collapsing scalarized neutron stars show scalar radiation energy of order 10^{-3} solar masses, orders of magnitude above the tensor quadrupolar emission, potentially observable to test modified gravity.
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Detectability of avoided crossings in black hole ringdowns
Bayesian analysis finds individual QNM frequencies near avoided crossings hard to resolve even under optimistic conditions, though collective AC waveform signatures may remain detectable if those modes dominate and slower-mode contamination is minimal.
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Ringing of rapidly rotating black holes in effective field theory
Leading-order cubic-curvature corrections to scalar quasinormal modes of black holes with spins up to 0.99M are computed numerically for modes up to l=5 with relative errors below 10^{-4}.
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GW231123: False Massive Graviton Signatures from Unmodeled Point-Mass Lensing
Unmodeled point-mass lensing produces a spurious nonzero graviton mass posterior in GW231123 that vanishes when lensing is included in the analysis.
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Probing (sub-)solar-mass black holes and superspinars with current and next-generation gravitational-wave observatories
Using TaylorF2 post-Newtonian waveforms truncated at ISCO, the study finds that Einstein Telescope and Cosmic Explorer can reach SNR of 100-350 and measure primary spin to 10^{-4}-10^{-3} precision for 0.1-2 solar mass exotic compact objects.
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The Impact of Spin Priors on Parameterized Tests of General Relativity
Spin prior choices propagate into tests of GR via the 1.5PN deviation parameter δφ̂3 in a non-trivial, event-dependent way, with stronger effects for short-inspiral events and partial degeneracy with χ_eff when the deviation is included.
-
Ringdown Analysis of GW250114 with Orthonormal Modes
Orthonormal QNM analysis of GW250114 raises the significance of the first overtone of the ℓ=m=2 mode from 82.5% to 99.9% and detects no significant deviation from Kerr predictions.
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Hawking area law in quantum gravity
Exact Hawking area law from black hole mergers restricts quantum gravity to singular Ricci-flat or specific regular black holes in Stelle and nonlocal theories, derives the standard entropy-area law, and realizes Barrow fractal black holes.
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Prompt Response from Plunging Sources in Schwarzschild Spacetime
The prompt response is ~1.2 times stronger than quasinormal mode excitation during inspiral and enables 99% accurate reconstruction of the full inspiral-merger-ringdown waveform when combined with other components.
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Tests of scalar polarizations with multi-messenger events
Bayesian analysis of GW170817 with PPE framework and EM polarization constraints shows mild preference for scalar mode in quadrupole harmonics and improves bounds on non-GR parameters by up to 60%.
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Mitigating Systematic Errors in Parameter Estimation of Binary Black Hole Mergers in O1-O3 LIGO-Virgo Data
Reanalysis of flagged LVK events with waveform uncertainty models produces consistent spin and precession inferences across raw/deglitched data and multiple waveform approximants.
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Improved Constraints on Non-Kerr Deviations from Binary Black Hole Inspirals Using GWTC-4 Data
Bayesian constraints from GWTC-4 binary black hole inspirals show Johannsen metric deformation parameters α13 and ε3 consistent with zero, supporting the Kerr hypothesis.