Black Hole Collisions with Thin Accretion Disks: OJ 287 and Small Mass Ratio Supermassive Black Hole Binary Candidates
Year: 2025
Type: article
Abstract: OJ 287 is the best-known supermassive black hole binary candidate in the nanohertz gravitational-wave band. It exhibits periodic flares every ∼12 yr, likely caused by collisions of a lower-mass secondary with the accretion disk surrounding a higher-mass primary. It is therefore an important benchmark for understanding black hole binary accretion in the approaching era of space-based gravitational-wave detectors and large electromagnetic surveys. Because the electromagnetic emission of the system is determined by a complex interplay of plasma, accretion, and radiation physics in strong gravity, numerical simulations are required for realistic modeling. We present the first global, three-dimensional, general relativistic magnetohydrodynamic simulations of OJ 287–like systems, namely lower-mass secondaries colliding with a radiatively cooled (thin) disk surrounding a higher-mass primary. We focus on disks with scale heights that are 10% of the distance from the primary and binary mass ratios of q = 0.1, 0.05, and 0.025 using an optically thin cooling prescription. We confirm the basic paradigm that impacts of the secondary on the disk can generate enough power to outshine the quiescent emission. The secondary also causes spiral shocks to form in the disk, enhanced accretion events, overall heating of the flow, and stochastic tilting of the disk, though these effects are small for q < 0.05. Our results can be extrapolated to the parameters of OJ 287 and similar systems, an important step on the path toward fully realistic simulations of accretion onto small mass ratio black hole binaries and predicting electromagnetic counterparts to low-frequency gravitational-wave detections.
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,400
Funders: National Science Foundation, Innovation, Science and Economic Development Canada, Vlaams Supercomputer Centrum, Flatiron Health, Government of Canada, Fonds Wetenschappelijk Onderzoek, Alliance de recherche numérique du Canada, Institut Périmètre de physique théorique, Ministry of Colleges and Universities, Canadian Space Agency, Natural Sciences and Engineering Research Council of Canada, Kavli Institute for Theoretical Physics, University of California, Santa Barbara, Compute Ontario
OpenAlex ID: W4415620906