Bridging Scales in Black Hole Accretion and Feedback: Magnetized Bondi Accretion in 3D GRMHD
- Harvard & Smithsonian, Cambridge, MA (United States); Harvard Univ., Cambridge, MA (United States)
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Harvard & Smithsonian, Cambridge, MA (United States); Harvard Univ., Cambridge, MA (United States)
- Harvard Univ., Cambridge, MA (United States); Yale Univ., New Haven, CT (United States)
Fueling and feedback couple supermassive black holes (SMBHs) to their host galaxies across many orders of magnitude in spatial and temporal scales, making this problem notoriously challenging to simulate. We use a multi-zone computational method based on the general relativistic magnetohydrodynamic (GRMHD) code KHARMA that allows us to span 7 orders of magnitude in spatial scale, to simulate accretion onto a non-spinning SMBH from an external medium with a Bondi radius of RB ≈ 2 × 105GM•/c2, where M• is the SMBH mass. For the classic idealized Bondi problem, spherical gas accretion without magnetic fields, our simulation results agree very well with the general relativistic analytic solution. Meanwhile, when the accreting gas is magnetized, the SMBH magnetosphere becomes saturated with a strong magnetic field. The density profile varies as ~r-1 rather than r-3/2 and the accretion rate $$\dot{M}$$ is consequently suppressed by over 2 orders of magnitude below the Bondi rate $$\dot{M}$$B. Here, we find continuous energy feedback from the accretion flow to the external medium at a level of $$\thicksim$$ 10-2$$\dot{M}$$c2 $$\thicksim$$ 5 X 10-5$$\dot{M}$$Bc2. Energy transport across these widely disparate scales occurs via turbulent convection triggered by magnetic field reconnection near the SMBH. Thus, strong magnetic fields that accumulate on horizon scales transform the flow dynamics far from the SMBH and naturally explain observed extremely low accretion rates compared to the Bondi rate, as well as at least part of the energy feedback.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA); National Science Foundation (NSF)
- Grant/Contract Number:
- 89233218CNA000001; 2138259; 2138286; 2138307; 2137603; 2138296
- OSTI ID:
- 2290325
- Report Number(s):
- LA-UR-23-31249; TRN: US2408915
- Journal Information:
- The Astrophysical Journal. Letters, Vol. 959, Issue 2; ISSN 2041-8205
- Publisher:
- IOP PublishingCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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