A new gravitational wave event reveals a binary black hole merger with total mass 190-265 solar masses, indicating black holes can form via gravitational-wave driven mergers beyond standard stellar channels.
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GWTC-4.0: Methods for Identifying and Characterizing Gravitational-wave Transients
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The Gravitational-Wave Transient Catalog (GWTC) is a collection of candidate gravitational-wave transient signals identified and characterized by the LIGO-Virgo-KAGRA Collaboration. Producing the contents of the GWTC from detector data requires complex analysis methods. These comprise techniques to model the signal; identify the transients in the data; evaluate the quality of the data and mitigate possible instrumental issues; infer the parameters of each transient; compare the data with the waveform models for compact binary coalescences; and handle the large amount of results associated with all these different analyses. In this paper, we describe the methods employed to produce the catalog's fourth release, GWTC-4.0, focusing on the analysis of the first part of the fourth observing run of Advanced LIGO, Advanced Virgo and KAGRA.
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representative citing papers
GWTC-5.0 adds 161 new compact binary coalescence candidates from O4b with p_astro >= 0.5, detailed properties for 104, all binary black holes, for a cumulative total of 390.
The first informative astrophysical calibration of gravitational-wave detectors is reported using GW240925 and GW250207.
First joint population inference on binary black hole eccentricity from GWTC-4 bounds the eccentric branching ratio below 5% at 90% confidence, with results consistent with quasi-circular models but highly model-dependent.
Numerical relativity analysis shows the direct wave frequency in binary black hole mergers correlates with horizon frequency only incidentally at χ_f ≈ 0.7 and has evolving damping time, making it unsuitable as a probe of remnant horizon properties or for testing Hawking's area law.
Presents new NSBH waveform models IMRPhenomXHM_NSBH, SEOBNRv5HM_ROM_NRTidalv3_NSBH, and IMRPhenomXPHM_NSBH incorporating higher modes and tidal effects via NRTidalv3 extensions, validated against NR simulations and applied to GWTC events.
The Targeted Detectability Range (TDR) incorporates sky localization, inclination constraints, and mass bounds from external messengers to evaluate gravitational-wave detectability for gamma-ray bursts observed during LIGO-Virgo-KAGRA's first three runs.
A reference-frequency-independent detection statistic for eccentric binary mergers is introduced and applied to GW200105, yielding ln B ≤ 0.9 in favor of the eccentric aligned-spin model over the quasi-circular precessing model.
A data-driven Bspline model for the binary black hole mass distribution from 137 GW events resolves three peaks and improves H0 precision by 12-21% over parametric alternatives.
Joint analysis of LVK standard sirens and DES 3x2pt data yields H0 = 67.9 +4.4/-4.3 km s^{-1} Mpc^{-1} at 6.4% precision while tightening the Omega_m constraint by 22%.
A new harmonic-decomposition template search for precessing binary black holes in LIGO O3 data improves sensitivity by up to 28% and reduces computational cost by up to 5x with no new detections.
SEOBNRv6EHM reduces parameter biases for eccentric binaries versus prior models and shows mild support for eccentricity in five catalog events plus comparable unbound fits for three high-mass events.
Targeted eccentric search detects GW200105 with SNR 13.4 and FAR <1/1000 yr, consistent with dynamical formation of the NSBH binary.
GWTC-4 data reveals a pair-instability gap at 44 M_⊙ in secondary black hole masses, interpreted as evidence for hierarchical mergers and used to constrain the S-factor for 12C(α,γ)16O.
Normalizing flows replace binned histograms for estimating multi-detector signal parameters in PyCBC, slashing storage by three orders of magnitude with under 0.05% sensitivity loss and up to 6.55% gains in specific cases.
Neural network surrogate approximates precessing compact binary gravitational waveforms up to 1000x faster than the base EOB model with validated accuracy.
Simulations show a 40-50 solar-mass black-hole cutoff is not guaranteed to be confidently recovered from GWTC-4-like catalogs, spurious detections are unlikely, and O4 data would reduce cutoff-mass uncertainty by at least 20 percent while yielding only a lower bound on the carbon-alpha reaction rate
GW250114 data constrains GR deviations in merger amplitude to 10% and frequency to 4% at 90% CL, with first bounds on the (4,4) mode frequency at 6%.
GW250114 data confirm the remnant is consistent with a Kerr black hole and bound the dominant quadrupolar mode frequency to within a few percent of the GR prediction, with constraints tighter than prior multi-event catalogs.
A stripped-star-motivated five-component model for binary black hole populations is preferred over the LVK baseline by a log10 Bayes factor of 7.69 and attributes the observed mass features to isolated, dynamical, and hierarchical formation channels.
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.
A time-frequency semi-coherent search pipeline detects stellar-mass BBH inspirals in LISA data down to coherent SNR of approximately 11-14 on the Yorsh data challenge for aligned-spin, low-eccentricity systems.
Dual-model analysis of 162 GW sources disfavors eccentricity for most events but finds potential evidence in GW200129, GW231001, and GW231123.
GW250114 data confirm the remnant black hole ringdown frequencies lie within 30% of Kerr predictions and that the final horizon area is larger than the sum of the progenitors' areas to high credibility.
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A universal framework to identify eccentric binary mergers: GW200105 case study
A reference-frequency-independent detection statistic for eccentric binary mergers is introduced and applied to GW200105, yielding ln B ≤ 0.9 in favor of the eccentric aligned-spin model over the quasi-circular precessing model.
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First measurement of the Hubble constant from a combined weak lensing and gravitational-wave standard siren analysis
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Search for Precessing Binary Black Holes in Advanced LIGO's Third Observing Run using Harmonic Decomposition
A new harmonic-decomposition template search for precessing binary black holes in LIGO O3 data improves sensitivity by up to 28% and reduces computational cost by up to 5x with no new detections.
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Eccentric and unbound compact binaries in the LIGO-Virgo-KAGRA catalog: parameter estimation and waveform systematics with SEOBNRv6EHM
SEOBNRv6EHM reduces parameter biases for eccentric binaries versus prior models and shows mild support for eccentricity in five catalog events plus comparable unbound fits for three high-mass events.
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Detection of GW200105 with a targeted eccentric search
Targeted eccentric search detects GW200105 with SNR 13.4 and FAR <1/1000 yr, consistent with dynamical formation of the NSBH binary.
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Evidence of the pair instability gap from black hole masses
GWTC-4 data reveals a pair-instability gap at 44 M_⊙ in secondary black hole masses, interpreted as evidence for hierarchical mergers and used to constrain the S-factor for 12C(α,γ)16O.
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Normalizing flows for density estimation in multi-detector gravitational-wave searches
Normalizing flows replace binned histograms for estimating multi-detector signal parameters in PyCBC, slashing storage by three orders of magnitude with under 0.05% sensitivity loss and up to 6.55% gains in specific cases.
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Fast neural network surrogate for multimodal effective-one-body gravitational waveforms from generically precessing compact binaries
Neural network surrogate approximates precessing compact binary gravitational waveforms up to 1000x faster than the base EOB model with validated accuracy.
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Plunge-Merger-Ringdown Tests of General Relativity with GW250114
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Compactness Peaks and Subpopulations: Probing Stellar Physics and Formation Channels of Merging Binary Black Holes
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Probing (sub-)solar-mass black holes and superspinars with current and next-generation gravitational-wave observatories
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Global time-frequency search for stellar-mass binary black holes in LISA
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Effects of formation channels and gravitational lensing on stochastic gravitational wave background
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An Implementation to Identify the Properties of Multiple Population of Gravitational Wave Sources
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No model-independent evidence for a peak in binary black hole spin (mis)alignments
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Training a neural network to rapidly identify candidate gravitational-wave events in the lower mass gap
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Investigating the effect of sensitivity of KAGRA on sky localization of gravitational-wave sources from compact binary coalescences
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Remnant recoil and host environments of GWTC-4.0 binary black-hole mergers
Five O4 gravitational-wave events prefer dynamical cluster formation; typical recoil kicks eject remnants from globular clusters but allow possible retention in nuclear star clusters, disfavoring efficient hierarchical growth in globular clusters.
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Implications of low neutron star merger rates for gamma-ray bursts, r-process production and Galactic double neutron stars
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GWTC-5.0: Methods for Identifying and Characterizing Gravitational-wave Transients
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The first decade of gravitational-wave measurements of black hole spins
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