A Mid-Thirties Crisis: Dissecting the Properties of Gravitational Wave Sources Near the 35 Solar Mass Peak

Abstract

One striking feature of binary black hole (BBH) mergers observed in the first decade of gravitational-wave astronomy is an excess of events with component masses around $35{\mathrm{M}}_{\odot }$. Multiple formation channels have been proposed to explain this excess. To distinguish among these channels, it is essential to examine their predicted population-level distributions across additional parameters. In this work, we focus on BBH mergers near the $35{\mathrm{M}}_{\odot }$ peak and infer the population distributions of primary mass ($m_1$), mass ratio ($q$), effective spin (${\chi }_{\mathrm{eff}}$), and redshift ($z$). We observe a gradual increase in the merger rate with $m_1$, rising by a factor of $3$ from $20{\mathrm{M}}_{\odot }$ to a peak around $34{\mathrm{M}}_{\odot }$, followed by a sharp, order-of-magnitude decline by $50{\mathrm{M}}_{\odot }$. This population also shows a weak preference for equal-mass mergers and has a ${\chi }_{\mathrm{eff}}$ distribution skewed toward positive values, with a median of zero excluded at approximately $90\%$ confidence. We find no significant $q-{\chi }_{\mathrm{eff}}$ correlation in the $35{\mathrm{M}}_{\odot }$ peak population, suggesting that lower-mass systems ($m_1<20{\mathrm{M}}_{\odot }$) likely drive the $q-{\chi }_{\mathrm{eff}}$ anti-correlation observed in the full BBH merger catalog. The redshift evolution of the merger rate is consistent with the cosmic star formation rate. We compare our findings with predictions from a wide range of formation channels. We find that common variants of the pair-instability supernova scenario, as well as hierarchical mergers, are incompatible with the observed features of the $35{\mathrm{M}}_{\odot }$ population. Ultimately, none of the formation channels we consider can explain all or even most of the features observed in this population. The ''mid-thirties'' of black hole mergers are in crisis.

Accepted Version in Classical and Quantum Gravity Special Edition: Gravitational Wave Physics and Astrophysics Ten Years After GW150914. Codes are Publicly Available on GitHub: https://github.com/SoumendraRoy/35Msun_GWTC3. A Frozen Version of the Codes with Produced Data are Also Available on Zenodo: https://zenodo.org/records/15778343

References in corpus (65)

• Advanced Virgo: a 2nd generation interferometric gravitational wave detector
• Cosmic Star Formation History
• Advanced LIGO
• GWTC-3: Compact Binary Coalescences Observed by LIGO and Virgo During the Second Part of the Third Observing Run
• GW190521: A Binary Black Hole Merger with a Total Mass of $150M_{\odot }$
• Pulsational Pair-Instability Supernovae
• Large Merger Recoils and Spin Flips From Generic Black-Hole Binaries
• The Effect of Pair-Instability Mass Loss on Black Hole Mergers
• Mind the gap: The location of the lower edge of the pair instability supernovae black hole mass gap
• Very massive stars, pair-instability supernovae and intermediate-mass black holes with the SEVN code
• Rotational mixing in massive binaries: detached short-period systems
• Constraints on the cosmic expansion history from GWTC-3
• 4-OGC: Catalog of gravitational waves from compact-binary mergers
• Estimating the final spin of a binary black hole coalescence
• A Highly Spinning and Aligned Binary Black Hole Merger in the Advanced LIGO First Observing Run
• 3-OGC: Catalog of gravitational waves from compact-binary mergers
• The Pair-Instability Mass Gap for Black Holes
• Where are LIGO's Big Black Holes?
• The cosmic merger rate of stellar black hole binaries from the Illustris simulation
• The cosmic merger rate density of compact objects: impact of star formation, metallicity, initial mass function and binary evolution
• New binary black hole mergers in the LIGO--Virgo O3a data
• The redshift evolution of the binary black hole merger rate: a weighty matter
• Mass Transfer from Giant Donors
• Short GRBs at the dawn of the gravitational wave era
• The Impact of Star Formation and Gamma-Ray Burst Rates at High Redshift on Cosmic Chemical Evolution and Reionization
• Accuracy Requirements for Empirically-Measured Selection Functions
• Model-independent inference on compact-binary observations
• Adiabatic mass loss in binary stars. III. From the base of the red giant branch to the tip of asymptotic giant branch
• Cover Your Basis: Comprehensive Data-Driven Characterization of the Binary Black Hole Population
• The Emergence of Structure in the Binary Black Hole Mass Distribution
• The impact of stellar rotation on the black hole mass-gap from pair-instability supernovae
• Observing intermediate-mass black holes and the upper--stellar-mass gap with LIGO and Virgo
• No peaks without valleys: The stable mass transfer channel for gravitational-wave sources in light of the neutron star-black hole mass gap
• Binary black holes population and cosmology in new lights: Signature of PISN mass and formation channel in GWTC-3
• Formation of Binary Black Holes Similar to GW190521 with a Total Mass of $\sim 150M_{\odot }$ from Population III Binary Star Evolution
• 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
• Ain't No Mountain High Enough: Semi-Parametric Modeling of LIGO-Virgos Binary Black Hole Mass Distribution
• Resolving the Stellar-Collapse and Hierarchical-Merger origins of the Coalescing Black Holes
• Non-parametric inference of the population of compact binaries from gravitational wave observations using binned Gaussian processes
• The time delay distribution and formation metallicity of LIGO-Virgo's binary black holes
• Do unequal-mass binary black hole systems have larger ${\chi }_{\text{eff}}$? Probing correlations with copulas in gravitational-wave astronomy
• Flexible and Fast Estimation of Binary Merger Population Distributions with Adaptive KDE
• Find the Gap: Black Hole Population Analysis with an Astrophysically Motivated Mass Function
• The Observed Rate of Binary Black Hole Mergers can be Entirely Explained by Globular Clusters
• New binary black hole mergers in the LIGO-Virgo O3b data
• Evidence for the evolution of black hole mass function with redshift
• Evidence for a correlation between binary black hole mass ratio and black-hole spins
• Unequal-mass, highly-spinning binary black hole mergers in the stable mass transfer formation channel
• Characterizing the observation bias in gravitational-wave detections and finding structured population properties
• Gravitational waves from Population III binary black holes are consistent with LIGO/Virgo O3a data for the chirp mass larger than $\sim 20M_{\odot }$
• Is there an excess of black holes around $20M_{\odot }$? Optimising the complexity of population models with the use of reversible jump MCMC
• Predictions of a simple parametric model of hierarchical black hole mergers
• Binary vision: The merging black hole binary mass distribution via iterative density estimation
• Forming merging double compact objects with stable mass transfer
• Internal circulation in tidally locked massive binary stars -- Consequences for double black hole formation
• Nonparametric analysis of correlations in the binary black hole population with LIGO-Virgo-KAGRA data
• Divergence in mass ratio distributions between low-mass and high-mass coalescing binary black holes
• Physical Models for the Astrophysical Population of Black Holes: Application to the Bump in the Mass Distribution of Gravitational Wave Sources
• LIGO-Virgo-KAGRA's Oldest Black Holes: Probing star formation at cosmic noon with GWTC-3
• No evidence that the binary black hole mass distribution evolves with redshift
• Exploring field-evolution and dynamical-capture coalescing binary black holes in GWTC-3
• The more accurately the metal-dependent star formation rate is modeled, the larger the predicted excess of binary black hole mergers
• Cosmology with Binary Neutron Stars: Does Mass-Redshift Correlation Matter?

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• On the Astrophysical Origin of Binary Black Hole Subpopulations: A Tale of Three Channels?
• Evidence for Three Subpopulations of Merging Binary Black Holes at Different Primary Masses
• Measurement prospects for the pair-instability mass cutoff with gravitational waves
• Reducing systematic uncertainties in gravitational-wave population analyses by increasing the detection threshold
• Characterizing Binary Black Hole Subpopulations in GWTC-4 with Binned Gaussian Processes: On the Origins of the $35M_{\odot }$ Peak