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تسجيل مستخدم جديدEfficiency of Super-Eddington Magnetically-Arrested Accretion
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Jonathan C. McKinney
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The radiative efficiency of super-Eddington accreting black holes (BHs) is explored for magnetically-arrested disks (MADs), where magnetic flux builds-up to saturation near the BH. Our three-dimensional general relativistic radiation magnetohydrodynamic (GRRMHD) simulation of a spinning BH (spin $a/M=0.8$) accreting at $sim 50$ times Eddington shows a total efficiency $sim 50%$ when time-averaged and total efficiency $gtrsim 100%$ in moments. Magnetic compression by the magnetic flux near the rotating BH leads to a thin disk, whose radiation escapes via advection by a magnetized wind and via transport through a low-density channel created by a Blandford-Znajek (BZ) jet. The BZ efficiency is sub-optimal due to inertial loading of field lines by optically thick radiation, leading to BZ efficiency $sim 40%$ on the horizon and BZ efficiency $sim 5%$ by $rsim 400r_g$ (gravitational radii) via absorption by the wind. Importantly, radiation escapes at $rsim 400r_g$ with efficiency $etaapprox 15%$ (luminosity $Lsim 50L_{rm Edd}$), similar to $etaapprox 12%$ for a Novikov-Thorne thin disk and beyond $etalesssim 1%$ seen in prior GRRMHD simulations or slim disk theory. Our simulations show how BH spin, magnetic field, and jet mass-loading affect the radiative and jet efficiencies of super-Eddington accretion.
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The radiative and jet efficiencies of thin magnetized accretion disks around black holes (BHs) are affected by BH spin and the presence of a magnetic field that, when strong, could lead to large deviations from Novikov-Thorne (NT) thin disk theory. T
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The exact time-dependent solution is obtained for a magnetic field growth during a spherically symmetric accretion into a black hole (BH) with a Schwarzschild metric. Magnetic field is increasing with time, changing from the initially uniform into a
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