Accretion of Low Angular Momentum Material onto Black Holes: Two-dimensional Magnetohydrodynamic Case

By D. Proga, M. C. B. Jila, U. Colorado, Boulder, Co., also Department of Astrophysical, Planetary Sciences, U. C. A. Boulder. 2003

143 citations recorded by the source corpus.

We report on the second phase of our study of slightly rotating accretion flows onto black holes. We consider magnetohydrodynamical (MHD) accretion flows with a spherically symmetric density distribution at the outer boundary but with spherical symmetry broken by the introduction of a small, latitude-dependent angular momentum and a weak radial magnetic field. We study accretion flows by means of numerical two-dimensional, axisymmetric, MHD simulations with and without resistive heating. Our main result is that the properties of the accretion flow depend mostly on an equatorial accretion torus that is made of the material that has too much angular momentum to be accreted directly. The torus accretes, however, because of the transport of angular momentum due to the magnetorotational instability (MRI). Initially, accretion is dominated by the polar funnel, as in the hydrodynamic inviscid case, where material has zero or very low angular momentum. At the later phase of the evolution, the torus thickens toward the poles and develops a corona or an outflow or both. Consequently, the mass accretion through the funnel is stopped. The accretion of rotating gas through the torus is significantly reduced compared with the accretion of nonrotating gas (i.e., the Bondi rate). It is also much smaller than the accretion rate in the inviscid, weakly rotating case. Our results do not change if we switch on or off resistive heating. Overall our simulations are very similar to those presented by Stone, Pringle, Hawley, and Balbus despite different initial and outer boundary conditions. Thus, we confirm that MRI is very robust and controls the nature of radiatively inefficient accretion flows. Although the time-averaged properties of our models approach a steady state, we find that the instantaneous mass-accretion rate in the latter stages of our simulations is highly time-dependent, with the inner flow displaying three generic flow patterns.

Subfields: Astronomy and Astrophysics, Geophysics

View Paper: https://www.semanticscholar.org/paper/753e3df8528f93641fba67b5d2f657f9f36d5bf3

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In Astronomy and Astrophysics

1. Bing Zhang
2. Ramesh Narayan
3. A. Tchekhovskoy
4. B. Metzger
5. A. Sa̧dowski
6. J. McKinney
7. E. Quataert
8. F. Yuan

In Geophysics

1. A. Sa̧dowski
2. J. McKinney
3. Ramesh Narayan
4. A. Tchekhovskoy
5. Yucong Zhu
6. B. Metzger
7. R. Penna
8. A. Philippov

Citations in the corpus

• THREE-DIMENSIONAL SIMULATIONS OF DYNAMICS OF ACCRETION FLOWS IRRADIATED BY A QUASAR (2007, methodology): “We expect that flow interaction can lead to time-dependent evolution and formation of inhomogeneous inflows and outflows (e.g., Proga & Begelman 2003b).”
• Gamma-Ray Bursts in the Swift Era (2007, background): “Based on MHD numerical simulations in other contexts (e.g. Proga & Begelman 2003) and theoretical arguments, Proga & Zhang (2006) argued that a magnetic barrier near the black hole may act as an effective modulatorof the accretion flow.”
• Mechanical feedback from active galactic nuclei in galaxies, groups and clusters (2012, background): “Using 2-dimensional magnetohydrodynamic simulations, Proga and Begelman (2003) concluded that the accretion rate for slowly rotating hot gas could be orders of magnitude less than the Bondi accretion rate.”
• Radiative efficiency, variability and Bondi accretion on to massive black holes: the transition from radio AGN to quasars in brightest cluster galaxies (2012, background): “There are also theoretical issues with Bondi accretion that include the ability to shed angular momentum and the zero central pressure requirement (Proga & Begelman 2003; Pizzolato & Soker 2005, 2010; Soker 2008; Narayan & Fabian 2011).”
• Energy, momentum and mass outflows and feedback from thick accretion discs around rotating black holes (2013, background): “Li, Ostriker & Sunyaev (2013, see also earlier work by Proga & Begelman 2003; Janiuk et al. 2009) ran a set of hydrodynamical axisymmetric simulations of low angular momentum gas.”
• Physical Processes Shaping Gamma-Ray Burst X-Ray Afterglow Light Curves: Theoretical Implications from the Swift X-Ray Telescope Observations (2005, background): “A magnetic-dominated accretion flow could also give rise to intermittent accretion flows due to interplay between the gravity and the magnetic barrier (Proga & Begelman 2003; Proga & Zhang 2006).”
• Black Hole Flares: Ejection of Accreted Magnetic Flux through 3D Plasmoid-mediated Reconnection (2021, methodology): “The magnetic flux decay is accompanied by the ejection of the accretion disk (Proga & Begelman 2003).”
• Unveiling the origin of X-ray flares in gamma-ray bursts (2010, background): “As discussed in the literature (Proga & Begelman 2003; King et al. 2005; Perna et al. 2006; Proga & Zhang 2006; Kumar et al. 2008; Lopez-Camara et al. 2009), there are several mechanisms that could keep the central engine active for a long time or reactivate it in a pseudo-random way.”
• Time-dependent models of accretion discs formed from compact object mergers (2008, background): “In addition, because RIAFs possess a positive Bernoulli parameter, a powerful viscously-driven outflow is likely (Blandford & Begelman 1999; Stone & Pringle 2001; Proga & Begelman 2003).”
• Nuclear Activity in Nearby Galaxies (2008, background): “The net accretion from the Bondi flow would be considerably reduced if the gas possesses some angular momentum at large radii (Proga & Begelman 2003)—as inevitably it must—but even so it seems likely that the BH still has plenty of food at its disposal.”
• General relativistic magnetohydrodynamic simulations of magnetically choked accretion flows around black holes (2012, methodology): “Other 2D MHD simulations have constant poloidal flux due to using a purely radial field (Proga & Begelman 2003), which gives results similar to torus simulations with limited poloidal flux.”
• Efficient Generation of Jets from Magnetically Arrested Accretion on a Rapidly Spinning Black Hole (2011, unknown): “Note that, unlike in 2D (axisymmetric) simulations (e.g. Proga & Begelman 2003), there is never a complete halt to the accretion (Igumenshchev et al. 2003) and even during flux eruptions, accretion proceeds via spiral-like structures, as seen in Fig.”
• Short-hard gamma-ray bursts (2007, unknown): “…(e.g., Hawley, 2000; Hawley & Krolik, 2002; Hawley & Balbus, 2002; Armitage, Reynolds & Chiang, 2001; Armitage & Reynolds, 2003; Proga, 2003; Proga & Begelman, 2003; Machida & Matsumoto, 2003; Kato, Mineshige & Shibata, 2004) to GR simulations using a Kerr metric in two dimensions (McKinney…”
• The late time evolution of gamma-ray bursts: ending hyperaccretion and producing flares (2006, unknown): “…the numerical simulation of a MHD collapsar model for GRBs carried our by Proga et al. (2003) and the results from a number of simulations of radiatively inefficient, MHD accretion flows onto a BH (Proga & Begelman 2003, PB03 hereafter; Igumenshchev, Narayan, &Abramowicz 2003, INA03 hereafter).”