Speaker
Description
OJ 287 is one of the most studied supermassive black hole binary candidates, modelled as featuring a primary of ∼10¹⁰ M☉ and a secondary of ∼10⁸ M☉ in a 12-year orbit. Its periodic optical flares, observed since the early 1900s, are thought to arise from the secondary’s interactions with the disc, yet the underlying mechanisms remain unclear. We investigate these processes using 3D smoothed particle hydrodynamics simulations with PHANTOM, evolving the system for over 250 years under different mass ratios. For a mass ratio of ∼10⁻³, the secondary’s disc crossings launch material above the disc plane and generate strong spiral density waves, boosting the primary’s accretion rate by 10–20%. In contrast, an equal-mass configuration (∼10⁸ M☉ each) with the same orbital period destroys the primary disc within ∼2 years, making such a scenario unlikely for OJ 287. Our results favour a highly unequal mass ratio and highlight the role of spiral density waves in driving accretion variability. These findings provide new constraints on OJ 287’s structure and inform models of supermassive black hole binary evolution and flare production.
