Compact Binary Coalescences: Astrophysical Processes and Lessons Learned

Spera, M.; Trani, Alessandro A.; Mencagli, Mattia

doi:10.3390/galaxies10040076

“…We adopt a low metallicity, so that stellar winds are irrelevant (Farmer et al 2019), to avoid the possible numerical complications of resolving models with winds (Renzo et al 2017). Low-metallicity environments are also likely to form some of the most massive stellar-mass BHs that can be detected as GW sources (Mapelli 2021;Vink et al 2021;Mandel & Farmer 2022;Spera et al 2022). Metallicities as low as Z = 0.02 Z e are enough to yield final He core masses of up to 140 M e , when adopting the recently updated and physically motivated Wolf-Rayet mass-loss schemes (Higgins et al 2021).…”

Section: Modelsmentioning

confidence: 99%

Resolving the Peak of the Black Hole Mass Spectrum

Farag

¹

,

Renzo

²

,

Farmer

³

et al. 2022

ApJ

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Gravitational-wave (GW) detections of binary black hole (BH) mergers have begun to sample the cosmic BH mass distribution. The evolution of single stellar cores predicts a gap in the BH mass distribution due to pair-instability supernovae (PISNe). Determining the upper and lower edges of the BH mass gap can be useful for interpreting GW detections of merging BHs. We use MESA to evolve single, nonrotating, massive helium cores with a metallicity of Z = 10−5, until they either collapse to form a BH or explode as a PISN, without leaving a compact remnant. We calculate the boundaries of the lower BH mass gap for S-factors in the range S(300 keV) = (77,203) keV b, corresponding to the ±3σ uncertainty in our high-resolution tabulated 12C(α,γ)16O reaction rate probability distribution function. We extensively test temporal and spatial resolutions for resolving the theoretical peak of the BH mass spectrum across the BH mass gap. We explore the convergence with respect to convective mixing and nuclear burning, finding that significant time resolution is needed to achieve convergence. We also test adopting a minimum diffusion coefficient to help lower-resolution models reach convergence. We establish a new lower edge of the upper mass gap as M lower ≃ 60 − 14 + 32 M ⊙ from the ±3σ uncertainty in the 12C(α, γ)16O rate. We explore the effect of a larger 3α rate on the lower edge of the upper mass gap, finding M lower ≃ 69 − 18 + 34 M ⊙. We compare our results with BHs reported in the Gravitational-Wave Transient Catalog.

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“…We adopt a low metallicity so that stellar winds are irrelevant (Farmer et al 2019), and to avoid the possible numerical complications of resolving models with winds (Renzo et al 2017). Low metallicity environments are also likely to form some of the most massive stellar mass BHs that can be detected as GW sources (Mapelli 2021;Vink et al 2021;Mandel & Farmer 2022;Spera et al 2022). Metallacities as low as Z = 0.02 Z are enough to yield final He core masses of up to 140 M when adopting recently updated and physically motivated Wolf-rayet mass loss schemes (Higgins et al 2021).…”

Section: Modelsmentioning

confidence: 99%

Resolving The Peak Of The Black Hole Mass Spectrum

Farag

¹

,

Renzo

²

,

Farmer

³

et al. 2022

0

View full text Add to dashboard Cite

Gravitational wave (GW) detections of binary black hole (BH) mergers have begun to sample the cosmic BH mass distribution. The evolution of single stellar cores predicts a gap in the BH mass distribution due to pair-instability supernova (PISN). Determining the upper and lower edges of the BH mass gap can be useful for interpreting GW detections from merging BHs. We use MESA to evolve single, non-rotating, massive helium cores with a metallicity of Z = 10 −5 until they either collapse to form a BH or explode as a PISN without leaving a compact remnant. We calculate the boundaries of the lower BH mass gap for S-factors in the range S(300 keV) = (77,203) keV b, corresponding to the ±3σ uncertainty in our high resolution tabulated 12 C(α,γ) 16 O reaction rate probability distribution function. We extensively test the temporal and mass resolution to resolve the theoretical peak of the BH mass spectrum across the BH mass gap. We explore the convergence with respect to convective mixing and nuclear burning, finding that significant time resolution is needed to achieve convergence. We also test adopting a minimum diffusion coefficient to help lower resolution models reach convergence. We establish a new lower edge of the upper mass gap as M lower 60 +32 −14 M from the ±3σ uncertainty in the 12 C(α, γ) 16 O rate. We explore the effect of a larger 3-α rate on the lower edge of the upper mass gap, finding M lower 69 +34 −18 M . We compare our results with BHs reported in the Gravitational-Wave Transient Catalog.

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“…In addition, examined the formation of wide-separate triples via dynamical interactions in young star clusters from simulations performed in Rastello et al (2020), and found that the ZKL oscillation plays an important role for the coalescence of compact binaries in such triples. For more comprehensive reviews on the formation of merging compact objects, including the triple evolution channel, we refer the reader to Mapelli (2021) and Spera et al (2022).…”

Section: Introductionmentioning

confidence: 99%

Dynamical Disruption Timescales and Chaotic Behavior of Hierarchical Triple Systems

Hayashi

¹

,

Trani

²

,

Suto

³

2022

ApJ

Self Cite

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We examine the stability of hierarchical triple systems using direct N-body simulations without adopting a secular perturbation assumption. We estimate their disruption timescales in addition to the mere stable/unstable criterion, with particular attention to the mutual inclination between the inner and outer orbits. First, we improve the fit to the dynamical stability criterion by Mardling & Aarseth widely adopted in the previous literature. Especially, we find that that the stability boundary is very sensitive to the mutual inclination; coplanar retrograde triples and orthogonal triples are much more stable and unstable, respectively, than coplanar prograde triples. Next, we estimate the disruption timescales of triples satisfying the stability condition up to 109 times the inner orbital period. The timescales follow the scaling predicted by Mushkin & Katz, especially at high e out where their random walk model is most valid. We obtain an improved empirical fit to the disruption timescales, which indicates that the coplanar retrograde triples are significantly more stable than the previous prediction. We furthermore find that the dependence on the mutual inclination can be explained by the energy transfer model based on a parabolic encounter approximation. We also show that the disruption timescales of triples are highly sensitive to tiny changes of the initial parameters, reflecting the genuine chaotic nature of the dynamics of those systems.

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Compact Binary Coalescences: Astrophysical Processes and Lessons Learned

Cited by 27 publications

References 581 publications

Resolving the Peak of the Black Hole Mass Spectrum

Resolving the Peak of the Black Hole Mass Spectrum

Resolving The Peak Of The Black Hole Mass Spectrum

Dynamical Disruption Timescales and Chaotic Behavior of Hierarchical Triple Systems

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