Efficient generation of jets from magnetically arrested accretion on a rapidly spinning black hole

ABSTRACT We describe global, 3D, time-dependent, non-radiative, general-relativistic, magnetohydrodynamic simulations of accreting black holes (BHs). The simulations are designed to transport a large amount of magnetic flux to the centre, more than the accreting gas can force into the BH. The excess magnetic flux remains outside the BH, impedes accretion, and leads to a magnetically arrested disc. We find powerful outflows. For a BH with spin parameter a = 0.5, the efficiency with which the accretion system generates outflowing energy in jets and winds is η≈ 30 per cent. For a = 0.99, we find η≈ 140 per cent, which means that more energy flows out of the BH than flows in. The only way this can happen is by…

• NS
  National Science Foundation

  Awards: 1041590, TG-AST080026N
• NA
  National Aeronautics and Space Administration

  Award: NNX11AE16G
• NC
  National Centre for Supercomputing Applications