Accretion onto a Supermassive Black Hole Binary before Merger
Year: 2024
Type: article
Abstract: While supermassive binary black holes (SMBBHs) inspiral toward merger they may also accrete matter from a surrounding disk. To study the dynamics of this system requires simultaneously describing the evolving spacetime and the magnetized plasma. We present the first relativistic calculation simulating two equal-mass, nonspinning black holes as they inspiral from a 20 M ( G = c = 1) initial separation almost to merger. Our results imply important observational consequences: for instance, the accretion rate M ̇ onto the black holes first decreases and then plateaus, dropping by only a factor of ∼3 despite the rapid inspiral. An estimated bolometric light curve follows the same profile, suggesting some merging SMBBHs may be significantly luminous past the predicted circumbinary disk decoupling. The minidisks are nonstandard: Reynolds, not Maxwell, stresses dominate, and they oscillate between two states. In one part of the cycle, “sloshing” streams transfer mass between minidisks, carrying kinetic energy at a rate sometimes as high as the peak minidisk bolometric luminosity. We also discover that episodic accretion drives time-varying minidisk tilts. These complex dynamics all contribute to unique cyclical behavior in the light curves of late-time inspiraling SMBBHs. The poloidal magnetic flux on the black holes is roughly constant at a dimensionless level ϕ ∼ 2–3, but doubles just before merger; for significant black hole spin, this flux predicts powerful jets with variability driven by binary dynamics, another potentially unique electromagnetic signature. This simulation is the first to employ our multipatch infrastructure P atchwork MHD, decreasing the computational expense to ∼3% of conventional single-grid methods’ cost.
Source: The Astrophysical Journal
Authors: Mark J. Avara, Julian H. Krolik, Manuela Campanelli, Scott C. Noble, Dennis Bowen, Taeho Ryu
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
Funders: National Science Foundation, U.S. Department of Energy, National Aeronautics and Space Administration, Aspen Center for Physics, National Centre for Supercomputing Applications, Universities Space Research Association, European Commission, Nuclear Safety and Security Commission, National Nuclear Security Administration, Goddard Space Flight Center, Los Alamos National Laboratory, H2020 European Research Council
Awards: G1011805105, G1017065088, G1092154682, G1279347439, G130463927, G1385423507, Leadership Class Scientific and Engineering Computing: Breaking Through the Limits, G2178269094, G2229954460, G2432923657, Collaborative Research: Deploying Curvilinear Coordinate and Multipatch Methods on Neutron Star Mergers, WoU-MMA: Collaborative Research: Supermassive Binary Black Holes: Accretion Dynamics and Electromagnetic Output, G2495227331, G2532392716, Collaborative Research: Curvilinear and Multipatch Methods for General Relativistic Astrophysics in the Gravitational Wave Era, G2952167421, From the accretion disk to the cluster halo: the multi-scale physics of black hole feedback, WoU-MMA: Collaborative Research: Supermassive Binary Black Hole Mergers: Accretion Dynamics and Electromagnetic Output, G3714573060, Collaborative Research: Curvilinear and Multipatch Methods for General Relativistic Astrophysics in the Gravitational Wave Era, Collaborative Research: Accretion Dynamics of Black Hole Mergers, G3951370523, G3982862247, MRI: Acquisition of an Advanced Computer Cluster for Computational Relativity and Gravitation, G434337789, MRI: Acquisition of an Advanced Computing Cluster for General Relativistic Astrophysics, Collaborative Research: Deploying Curvilinear Coordinate and Multipatch Methods on Neutron Star Mergers, G4810716312, Sustained-Petascale In Action: Blue Waters Enabling Transformative Science And Engineering, Computational Relativity and Gravitation at Petascale: Simulating and Visualizing Astrophysically Realistic Compact Binaries, G5127309730, G5606180237, G5737679380, G6410514744, MRI: Acquisition of a Computing Cluster for Gravitational-Wave and Multimessenger Astrophysics in the Era of LIGO Detections, G70659677, Collaborative Research: Accretion Dynamics of Black Hole Mergers, Programs on Critical Problems in Physics, Astrophysics and Biophysics at the Aspen Center for Physics, G8210734700, Kavli Institute for Theoretical Physics, MRI: Acquisition of a Computing System for Large Simulation Data Sets in Multimessenger Astrophysics
OpenAlex ID: W4403418573