The Fate of Transonic Shocks around Black Holes and Their Future Astrophysical Implications

Abstract Theoretical models have long predicted the existence of shocks in multitransonic accretion flows onto a black hole, yet their fate under general relativistic simulations has not been fully tested. In this study, we present results from high-resolution two-dimensional general relativistic hydrodynamic and general relativistic magnetohydrodynamic simulations of low angular momentum accretion flows onto Kerr black holes, focusing on the formation of shocks in transonic accretion flow. We demonstrate that for specific combinations of energy and angular momentum, global shock solutions naturally emerge between multiple sonic points. These shocks are sustained in both corotating and counterrotating cases, and their locations depend on specific energy, angular momentum, and the spin of the black hole, which is in good agreement with analytical solutions. In magnetized flows, weak magnetic fields preserve the shock structure, whereas strong fields suppress it, enhancing turbulence and driving powerful, magnetically dominated jets/outflows. The strength and structure of the outflow also depend on a black hole spin and magnetization, with higher black hole spin parameters leading to faster jets. Shock solutions are found only in super-Alfvénic regions, where kinetic forces dominate. Our findings provide important insights into the physics of hot corona formation and jet launching in low angular momentum accretion systems such as Sgr A* (weak jet/outflow) and X-ray binaries.