发表机构
Columbia University; Institute of Science and Technology Austria (ISTA); New York University（哥伦比亚大学; 奥地利科学技术研究所; 纽约大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过80组不同质量比和偏心率的超大质量双黑洞流体动力学模拟，明确偏心且质量不等双黑洞的优先吸积行为，发现低偏心率、低质量比双黑洞的次级黑洞吸积优势最强，该吸积率变化与环绕双黑洞的气体盘进动相关，还揭示了其对双黑洞演化及观测的影响。
AI 中文摘要
超大质量双黑洞（SMBBHs）预计被环绕双黑洞的气体盘（CBDs）包围，这些气体盘通过引力和吸积作用影响双黑洞。已有研究表明，双黑洞会经历“优先吸积”现象，即一个黑洞（BH）在数百个轨道周期内的吸积量超过另一个，但这种不对称性尚未被完整描述或理解。本研究利用80组质量比（$q_b$）和偏心率（$e_b$）各不相同的超大质量双黑洞流体动力学模拟，旨在可靠地刻画优先吸积的行为、确定其与环绕双黑洞气体盘结构的关系，并研究其观测后果。我们在所有模拟中表征了吸积率比值$\lambda(t) \equiv \dot{M}_2(t)/\dot{M}_1(t)$和质量比变化率$\dot{q}_b \equiv d/dt(M_2/M_1)$。我们证实次级黑洞倾向于比主黑洞吸积更多（$\lambda \geq 1$），并发现这种吸积偏好对于低$e_b$、低$q_b$的双黑洞最强，且在高$e_b$时吸积的时间变异性增强。我们还发现：（i）$\lambda$的时间变异性与环绕双黑洞气体盘的进动相关；（ii）单个双黑洞中可能存在亚爱丁顿和超爱丁顿吸积；（iii）对于高偏心率、高$q_b$的双黑洞，气体驱动的质量均等化过程会变得特别缓慢，这表明一些双黑洞可能在类星体的$30\,\mathrm{Myr}$寿命内无法达到$q_b=1$，因此LISA可用于约束超大质量双黑洞的吸积历史。我们的发现还表明，周期性闪烁的喷流是许多双黑洞的潜在可观测特征。
英文摘要
Supermassive binary black holes (SMBBHs) are expected to be surrounded by circumbinary disks (CBDs) which affect the binary through gravitational forces and accretion. It has been reported that the binary can experience ``preferential accretion'' where one black hole (BH) out-accretes the other for hundreds of orbits, but this asymmetry has yet to be fully described or understood. In this work, we utilize a suite of 80 SMBBH hydrodynamical simulations with varying mass ratios ($q_b$) and eccentricity ($e_b$) in order to robustly delineate the behavior of preferential accretion, determine its relationship to the structure of the CBD, and study its observational consequences. We characterize the accretion-rate ratio $λ(t) \equiv \dot{M}_2(t)/\dot{M}_1(t)$ and the mass-ratio rate of change $\dot{q}_b \equiv d/dt(M_2/M_1)$ across the suite. We confirm that the secondary tends to out-accrete the primary ($λ\geq 1$), and find this preference to be strongest for low-$e_b$, low-$q_b$ binaries and increasingly time-variable toward high $e_b$. We also find that (i) the time-variability of $λ$ tracks the precession of the CBD, (ii) there can be sub- and super-Eddington accretion in a single binary, and (iii) the gas-driven approach toward equal mass becomes particularly slow for highly eccentric, high $q_b$ binaries, suggesting that some binaries may not reach $q_b=1$ within the $30\,\mathrm{Myr}$ lifetime of a quasar and therefore allowing LISA to constrain the accretion history of SMBBHs. Our findings also suggest that periodically flickering jets are a potential observable signature of many binaries.
