基于详细双星演化模型的大质量双黑洞并合
High-mass binary black hole mergers from detailed binary evolution models
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中文总结 AI 辅助
本研究用POSYDON模拟大质量双黑洞并合族群，发现完全保守吸积与观测不符，爱丁顿极限型和GRRMHD参考型吸积需结合诞生kick，仍需额外通道解释负χ_eff系统占比及次黑洞高自旋问题。
中文摘要 AI 辅助
引力波观测揭示了一个双黑洞（BBH）并合族群，其主黑洞质量约40倍太阳质量，延伸至对不稳定质量间隙内甚至可能超出该间隙，且质量比可能呈平坦分布，有效自旋χ_eff分布更宽。本研究探讨孤立双星演化中稳定质量转移阶段的超爱丁顿吸积，能否在主黑洞质量、质量比及χ_eff分布上产生与观测特性一致的BBH并合。使用POSYDON工具，模拟主黑洞质量约40倍太阳质量以上的BBH并合族群，设置三种黑洞吸积效率：爱丁顿极限型、GRRMHD参考型及完全保守型，还调整了诞生kick强度，包括高黑洞质量下的强kick。研究发现，超爱丁顿吸积不会抑制大质量区的BBH并合；完全保守吸积会使POSYDON模拟的BBH并合增加，在χ_eff=0.6处有一个与kick无关的强峰，质量比在q≈0.5处有一个尖锐峰，而观测倾向于χ_eff=0.0和更平坦的质量比分布；GRRMHD参考型与爱丁顿极限型吸积与观测到的主黑洞质量和质量比分布兼容，但需要诞生kick来产生负χ_eff。对主黑洞质量、质量比及χ_eff分布的联合分析，为双星演化物理提供了强约束，不支持完全保守黑洞吸积作为大质量BBH并合的主导形成机制；爱丁顿极限型和GRRMHD参考型方案结合适度kick可解释部分大质量族群，但仍需额外形成通道以解释负χ_eff系统的高占比及次黑洞的高自旋。
英文摘要
Gravitational-wave observations reveal a population of binary black hole (BBH) mergers with primary masses above ${\sim}40\,\mathrm{M}_\odot$, extending into and potentially beyond the pair-instability mass gap, with a possibly flat mass-ratio and broader χ_\mathrm{eff} distribution. We investigate whether super-Eddington accretion during stable mass transfer in isolated binary evolution can produce BBH mergers consistent with these properties across primary BH mass, mass-ratio, and χ_\mathrm{eff} distributions. Using POSYDON, we simulate BBH merger populations with primary BH masses above ${\sim}40\,\mathrm{M}_\odot$, under three BH accretion efficiencies: Eddington-limited, GRRMHD-informed, and fully conservative. We additionally vary the natal kick strength, including strong kicks at high BH masses. We find that super-Eddington accretion does not suppress BBH mergers in the high-mass regime. Fully-conservative accretion leads to an increase of BBH mergers in POSYDON with a strong kick-independent peak at $χ_\mathrm{eff}=0.6$ and a sharp mass-ratio peak at $q\sim0.5$, whereas observations favor $χ_\mathrm{eff}=0.0$ and a flatter mass-ratio distribution. The GRRMHD-informed and Eddington-limited accretion are compatible with the observed primary BH mass and mass ratio distribution, but require natal kicks to populate negative χ_\mathrm{eff}. A joint analysis of the primary BH mass, mass ratio, and χ_\mathrm{eff} distributions provides strong constraints on binary evolution physics, and disfavor fully-conservative BH accretion as the dominant formation mechanism for high-mass BBH mergers. The Eddington-limited and GRRMHD-informed prescriptions with modest kicks can explain part of the high-mass population, but an additional formation channel is still needed to account for the high fraction of negative χ_\mathrm{eff} systems and high secondary BH spins.
