Characterizing Binary Black Hole Subpopulations in GWTC-4 with Binned Gaussian Processes: On the Origins of the $35M_{\odot }$ Peak

Abstract

Understanding the astrophysical origins of binary black holes requires accurate and flexible modeling of multi-dimensional population properties. In this \textit{Letter}, using a data-driven framework based on binned Gaussian processes, we characterize the joint distribution of BBH primary masses, mass ratios, and effective inspiral spins. We identify three distinct subpopulations in the GWTC-4 sample of observations and investigate their astrophysical origins. We find that only one of the three subpopulations exhibits the $35M_{\odot }$ peak, which is characterized by a strong preference for equal mass systems and isotropic spin orientations. Our inferred distributions are consistent with a predominantly dynamical origin of this feature. By comparing with theoretical simulations, we further show that the subpopulation that exhibits the $35M_{\sun}$ peak can exclusively comprise dynamically assembled systems in globular clusters, specifically if black hole birth spins are in the range~$(0.1-0.2)$, whereas the other two subpopulations require substantial contributions from alternative formation channels. We constrain the \textit{lower bound} on the merger rate of BBHs in globular clusters to be $0.69_{-0.33}^{+0.23}{\mathrm{Gpc}}^{-3}{\mathrm{yr}}^{-1}$, which is consistent with most theoretical predictions(that can range from $0.2-57{\mathrm{Gpc}}^{-3}{\mathrm{yr}}^{-1}$ depending on modeling assumptions). We conclude that dynamical formation in globular clusters remains a strong candidate for the origin of this excess near $30-40M_{\odot }$ and that more data and targeted parametric models are necessary to rigorously establish this interpretation.

Journal Accepted Version, 20 pages, 11 figures

References in corpus (93)

• Planck 2015 results. XIII. Cosmological parameters
• Advanced Virgo: a 2nd generation interferometric gravitational wave detector
• GWTC-1: A Gravitational-Wave Transient Catalog of Compact Binary Mergers Observed by LIGO and Virgo during the First and Second Observing Runs
• Advanced LIGO
• MCMC using Hamiltonian dynamics
• dynesty: A Dynamic Nested Sampling Package for Estimating Bayesian Posteriors and Evidences
• GW190814: Gravitational Waves from the Coalescence of a 23 M${}_{\odot }$ Black Hole with a 2.6 M${}_{\odot }$ Compact Object
• Bilby: A user-friendly Bayesian inference library for gravitational-wave astronomy
• Frequency-domain gravitational waves from non-precessing black-hole binaries. II. A phenomenological model for the advanced detector era
• A Comprehensive Study of Binary Compact Objects as Gravitational Wave Sources: Evolutionary Channels, Rates, and Physical Properties
• Frequency-domain gravitational waves from non-precessing black-hole binaries. I. New numerical waveforms and anatomy of the signal
• Pulsational Pair-Instability Supernovae
• Black hole mergers in the universe
• A new route towards merging massive black holes
• Rapid and Bright Stellar-mass Binary Black Hole Mergers in Active Galactic Nuclei
• Assisted Inspirals of Stellar Mass Black Holes Embedded in AGN Disks: Solving the "Final AU Problem"
• Bayesian inference for compact binary coalescences with BILBY: Validation and application to the first LIGO--Virgo gravitational-wave transient catalogue
• Secular evolution of compact binaries near massive black holes: gravitational wave sources and other exotica
• Extracting distribution parameters from multiple uncertain observations with selection biases
• The chemically homogeneous evolutionary channel for binary black hole mergers: rates and properties of gravitational-wave events detectable by advanced LIGO
• Mind the gap: The location of the lower edge of the pair instability supernovae black hole mass gap
• Formation of the first three gravitational-wave observations through isolated binary evolution
• The evolutionary roads leading to low effective spins, high black hole masses, and O1/O2 rates of LIGO/Virgo binary black holes
• Very massive stars, pair-instability supernovae and intermediate-mass black holes with the SEVN code
• Illuminating Black Hole Binary Formation Channels with Spins in Advanced LIGO
• Cosmological black hole spin evolution by mergers and accretion
• Black Holes: The Next Generation -- Repeated Mergers in Dense Star Clusters and their Gravitational-Wave Properties
• Binary black hole mergers from field triples: properties, rates and the impact of stellar evolution
• Are merging black holes born from stellar collapse or previous mergers?
• Most Black Holes are Born Very Slowly Rotating
• Accelerating Compact Object Mergers in Triple Systems with the Kozai Resonance: A Mechanism for "Prompt" Type Ia Supernovae, Gamma-Ray Bursts, and Other Exotica
• Lidov-Kozai Cycles with Gravitational Radiation: Merging Black Holes in Isolated Triple Systems
• The effect of the metallicity-specific star formation history on double compact object mergers
• Distinguishing Spin-Aligned and Isotropic Black Hole Populations With Gravitational Waves
• Possible Indirect Confirmation of the Existence of Pop III Massive Stars by Gravitational Wave
• Exoplanet population inference and the abundance of Earth analogs from noisy, incomplete catalogs
• Merging black holes in young star clusters
• Dynamics of stellar black holes in young star clusters with different metallicities - II. Black hole-black hole binaries
• Hierarchical mergers of stellar-mass black holes and their gravitational-wave signatures
• The origin of spin in binary black holes: Predicting the distributions of the main observables of Advanced LIGO
• Measuring the binary black hole mass spectrum with an astrophysically motivated parameterization
• The spin of the second-born black hole in coalescing binary black holes
• The final spin from binary black holes in quasi-circular orbits
• Constraints from gravitational wave detections of binary black hole mergers on the ${}^{12}\mathrm{C}{\left(\alpha ,\gamma \right)}^{16}\mathrm{O}$ rate
• Greatly enhanced merger rates of compact-object binaries in non-spherical nuclear star clusters
• Reconstructing phenomenological distributions of compact binaries via gravitational wave observations
• The impact of pair-instability mass loss on the binary black hole mass distribution
• Evidence for hierarchical black hole mergers in the second LIGO--Virgo gravitational-wave catalog
• The redshift evolution of the binary black hole merger rate: a weighty matter
• Black Hole and Neutron Star Binary Mergers in Triple Systems: Merger Fraction and Spin-Orbit Misalignment
• Monte-Carlo simulations of black hole mergers in AGN disks: Low ${\chi }_{\mathrm{eff}}$ mergers and predictions for LIGO
• Populating the upper black hole mass gap through stellar collisions in young star clusters
• Binary black holes in young star clusters: the impact of metallicity
• A Triple Origin for the Heavy and Low-Spin Binary Black Holes Detected by LIGO/Virgo
• Joint constraints on the field-cluster mixing fraction, common envelope efficiency, and globular cluster radii from a population of binary hole mergers via deep learning
• Accuracy Requirements for Empirically-Measured Selection Functions
• Modeling Dense Star Clusters in the Milky Way and Beyond with the Cluster Monte Carlo Code
• Black Hole Coagulation: Modeling Hierarchical Mergers in Black Hole Populations
• Model-independent inference on compact-binary observations
• A Parallel Monte Carlo Code for Simulating Collisional N-body Systems
• The Emergence of Structure in the Binary Black Hole Mass Distribution
• No peaks without valleys: The stable mass transfer channel for gravitational-wave sources in light of the neutron star-black hole mass gap
• Formation of Binary Black Holes Similar to GW190521 with a Total Mass of $\sim 150M_{\odot }$ from Population III Binary Star Evolution
• Dynamical formation & scattering of hierarchical triples: Cross sections, Kozai-Lidov oscillations, and collisions
• Coalescing black hole binaries from globular clusters: mass distributions and comparison to gravitational wave data from GWTC-3
• A Parameter-Free Tour of the Binary Black Hole Population
• Understanding the high-mass binary black hole population from stable mass transfer and super-Eddington accretion in BPASS
• Suspicious Siblings: The Distribution of Mass and Spin Across Component Black Holes in Isolated Binary Evolution
• GWTC-4.0: Updating the Gravitational-Wave Transient Catalog with Observations from the First Part of the Fourth LIGO-Virgo-KAGRA Observing Run
• An alternative interpretation of GW190412 as a binary black hole merger with a rapidly spinning secondary
• GWTC-4.0: An Introduction to Version 4.0 of the Gravitational-Wave Transient Catalog
• Signatures of mass ratio reversal in gravitational waves from merging binary black holes
• What You Don't Know Can Hurt You: Use and Abuse of Astrophysical Models in Gravitational-wave Population Analyses
• Evidence for a correlation between binary black hole mass ratio and black-hole spins
• Probing Extremal Gravitational-Wave Events with Coarse-Grained Likelihoods
• The locations of features in the mass distribution of merging binary black holes are robust against uncertainties in the metallicity-dependent cosmic star formation history
• Filling the Black Hole Mass Gap: Avoiding Pair Instability in Massive Stars through Addition of Non-Nuclear Energy
• Avoiding selection bias in gravitational wave astronomy
• Constraints on axionlike particles from a combined analysis of three flaring $\text{Fermi}$ flat-spectrum radio quasars
• Gravitational waves from Population III binary black holes are consistent with LIGO/Virgo O3a data for the chirp mass larger than $\sim 20M_{\odot }$
• Predictions of a simple parametric model of hierarchical black hole mergers
• Which black hole is spinning? Probing the origin of black-hole spin with gravitational waves
• Binary vision: The merging black hole binary mass distribution via iterative density estimation
• Nonparametric analysis of correlations in the binary black hole population with LIGO-Virgo-KAGRA data
• Physical Models for the Astrophysical Population of Black Holes: Application to the Bump in the Mass Distribution of Gravitational Wave Sources
• Spin Doctors: How to diagnose a hierarchical merger origin
• Evidence of the pair instability gap from black hole masses
• Gravitational-wave Observations Suggest Most Black Hole Mergers Form in Triples
• Reexamining Evidence of a Pair-Instability Mass Gap in the Binary Black Hole Population
• A Mid-Thirties Crisis: Dissecting the Properties of Gravitational Wave Sources Near the 35 Solar Mass Peak
• Great Balls of FIRE IV. The contribution of massive star clusters to the astrophysical population of merging binary black holes
• A new group of low-spin $50-70M_{\odot }$ Black Holes and the high pair-instability mass cutoff
• Probing Spin-Orbit Resonances with the Binary Black Hole Population