TAPIR Seminar
As black holes accrete surrounding gas, they often produce relativistic, collimated outflows, or jets. Jets are expected to form in the vicinity of a black hole, making them powerful probes of strong-field gravity. However, how the properties of the jet connect to those of the accretion flow and the black hole (e.g. black hole spin) remains an area of active research. Recent progress in large-scale computer simulation techniques enables studies of jet formation in unprecedented detail. For the first time, 3D general relativistic magnetohydrodynamic (GRMHD) numerical simulations allow one to determine from first principles the maximum efficiency with which accretion onto black holes can power relativistic jets. I will present the dependence of this maximum efficiency on black hole spin and discuss how this dependence allows one to probe strong-field gravity. In realistic astrophysical systems, the angular momentum vector of the accretion flow can be tilted relative to the spin axis of the black hole. I will present the first simulations of jets from such tilted accretion systems and discuss their observational signatures. I will finish by describing the ongoing effort to develop the next-generation GRMHD code that quantitatively accounts for the interaction of gas and radiation.