Accretion, Jets, and Recoil in Merging Supermassive Binary Black Holes
ORAL
Abstract
Supermassive black holes (SMBHs) are ubiquitous in galactic centers, and their mergers, driven by hierarchical galaxy formation, rank among the most powerful events in the Universe. Supermassive binary black hole (SMBBH) mergers release immense energy via gravitational waves (GWs), with peak luminosities rivaling the combined output of all stars in the observable cosmos. A key consequence of these mergers is the gravitational recoil of the remnant black hole, propelled by the anisotropic emission of GWs. The magnitude of this recoil depends sensitively on binary parameters such as spin configuration and mass ratio, and capturing its full complexity requires numerical relativity to resolve the highly non-linear merger dynamics.
We present the first 3D general relativistic magnetohydrodynamic (GRMHD) simulation of a SMBBH merger with misaligned spins embedded in an equilibrated circumbinary disk (CBD). Specifically, we model the “hang-up kick” configuration, where individual black hole spins are inclined 45° relative to the orbital angular momentum. Our simulation tracks the final 40 orbits of inspiral, merger, and recoil, following an initial phase of 165 orbits during which the CBD evolves toward equilibrium. We find that relativistic jets, initially aligned with individual spins, reorient toward the binary’s total angular momentum at larger scales. Post-merger, the remnant black hole receives a recoil exceeding 1000 km/s yet retains its gravitationally bound CBD. The jet preserves its pre-merger orientation, and the dominant luminosity emerges from regions near the black hole, suggesting that the accretion disk remains the brightest feature for hours, potentially observable by instruments such as LISA.
These results establish a first-principles framework for modeling SMBH recoil in active galactic nuclei (AGNs), offering predictive power for future multimessenger observations and advancing our understanding of black hole-galaxy coevolution.
We present the first 3D general relativistic magnetohydrodynamic (GRMHD) simulation of a SMBBH merger with misaligned spins embedded in an equilibrated circumbinary disk (CBD). Specifically, we model the “hang-up kick” configuration, where individual black hole spins are inclined 45° relative to the orbital angular momentum. Our simulation tracks the final 40 orbits of inspiral, merger, and recoil, following an initial phase of 165 orbits during which the CBD evolves toward equilibrium. We find that relativistic jets, initially aligned with individual spins, reorient toward the binary’s total angular momentum at larger scales. Post-merger, the remnant black hole receives a recoil exceeding 1000 km/s yet retains its gravitationally bound CBD. The jet preserves its pre-merger orientation, and the dominant luminosity emerges from regions near the black hole, suggesting that the accretion disk remains the brightest feature for hours, potentially observable by instruments such as LISA.
These results establish a first-principles framework for modeling SMBH recoil in active galactic nuclei (AGNs), offering predictive power for future multimessenger observations and advancing our understanding of black hole-galaxy coevolution.
*NASA Theory and Computational Astrophysics Network (TCAN) grant, 80NSSC24K0100, NSF awards AST-2009330, AST-1516150, AST-2319326, PHY-2110338, PHY-1707946, PHY-2207920, PHY-2513442, PHY-2409706, and OAC-2411068. Texas Advanced Computing Center (TACC) Frontera allocations PHY-20010 and AST-20021.
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Publication: https://doi.org/10.48550/arXiv.2510.05883
https://doi.org/10.48550/arXiv.2509.10319
Presenters
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Maria Chiara de Simone
- Rochester Institute of Technology