Bardeen-Petterson Alignment, Jets and Magnetic Truncation in GRMHD Simulations of Tilted Thin Accretion Discs

Understand

Prevalent around luminous accreting black holes, thin discs are challenging to resolve in numerical simulations.

• When the disc and black hole angular momentum vectors are misaligned, the challenge becomes extreme, requiring adaptive meshes to follow the disc proper as it moves through the computational grid.
• With our new high-performance general relativistic magnetohydrodynamic (GRMHD) code H-AMR we have simulated the thinnest accretion disc to date, of aspect ratio H/R~0.03, around a rapidly spinning (a=0.9375) black hole, using a cooling function.
• Initially tilted at 10 degrees, the disc warps inside r~5 r_g into alignment with the black hole, where r_g is the gravitational radius.