A numerical study of relativistic Bondi-Hoyle accretion onto a moving black hole: Axisymmetric computations in a Schwarzschild background

A fully relativistic numerical study of nonspherical Bondi-Hoyle accretion onto a Schwarzschild black hole is presented. The simulations are performed in axisymmetry with a high-resolution shock-capturing numerical scheme that makes use of a linearized Riemann solver as a key ingredient to handle shock waves. A broad family of initial flow parameters is considered. The main differences among the accretion patterns of the different models is discussed. A detailed comparative study with a previous relativistic simulation is performed. The results of this study reveal a qualitative agreement in the morphology and dynamics of the flow. However, there are important discrepancies concerning quantitative results as the mass accretion rates. All models evolved numerically in this paper relax to a final steady state accretion pattern, and, as the simulations are performed in axisymmetry, no evidence of any kind of instabilities (e.g., flip-flop) is present.