The Fate of Nonradiative Magnetized Accretion Flows: Magnetically Frustrated Convection

Pen, Ue-Li; Matzner, Christopher D.; Wong, Shingkwong

doi:10.1086/379339

Cited by 74 publications

(69 citation statements)

References 24 publications

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“…[See the electronic edition of the Journal for a color version of this figure. ] correspond to generalized wind models (Blandford & Begelman 1999). Numerical hydro and MHD simulations give s 0 anywhere in the range from about 0.7 to 1 (Igumenshchev et al , 2003Pen et al 2003). On the other hand, a model for the accreting supermassive black hole Sgr A Ã at the Galactic center gives s 0 $ 0:3 (Yuan et al 2003).…”

Section: More Quantitative Resultsmentioning

confidence: 97%

Neutrino‐dominated Accretion and Supernovae

Kohri

Narayan

Piran

2005

ApJ

220

354

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We suggest that part of the infalling material during the core collapse of a massive star goes into orbit around the compact core to form a hot, dense, centrifugally supported accretion disk whose evolution is strongly influenced by neutrino interactions. Under a wide range of conditions, this neutrino-dominated accretion flow will be advection dominated and will develop a substantial outflowing wind. We estimate the energy carried out in the wind and find that it exceeds 10 50 ergs for a wide range of parameters and even exceeds 10 51 ergs for reasonable parameter choices. We propose that the wind energy will revive a stalled shock and will help produce a successful supernova explosion. We discuss the role of the disk wind in both prompt and delayed explosions. While both scenarios are feasible, we suggest that a delayed explosion is more likely and perhaps even unavoidable. Finally, we suggest that the disk wind may be a natural site for r-process nucleosynthesis.

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Section: More Quantitative Resultsmentioning

confidence: 97%

Neutrino‐dominated Accretion and Supernovae

Kohri

Narayan

Piran

2005

ApJ

220

354

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“…Future observations of PSRJ1745−2900 will better constrain the magnetic field structure around SgrA * and can potentially be used to test if the accretion flow becomes magnetically dominated (Pen et al 2003).…”

Section: A Physical Model Based On the Depolarizationmentioning

confidence: 99%

Large Magneto-ionic Variations toward the Galactic Center Magnetar, PSR J1745-2900

Desvignes

Eatough

Pen

et al. 2018

ApJL

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Polarized radio emission from PSRJ1745−2900 has already been used to investigate the strength of the magnetic field in the Galactic center (GC), close to SagittariusA * . Here we report how persistent radio emission from this magnetar, for over four years since its discovery, has revealed large changes in the observed Faraday rotation measure (RM), by up to 3500 rad m −2 (a 5% fractional change). From simultaneous analysis of the dispersion measure, we determine that these fluctuations are dominated by variations in either the projected magnetic field or the free electron content within the GC, along the changing line of sight to the rapidly moving magnetar. From a structure function analysis of RM variations, and a recent epoch of rapid change of RM, we determine a minimum scale of magneto-ionic fluctuations of size ∼2 au at the GC distance, inferring PSRJ1745−2900 is just ∼0.1 pc behind an additional scattering screen.

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“…Numerous two-and three-dimensional global simulations of RIAFs have been performed in hydrodynamics (2D- Stone et al 19993D-Igumenshchev et al 2000) as well as in magnetohydrodynamics (MHD; 2D- Stone & Pringle 2001;3D-Hawley et al 2001, Machida et al 2001, Hawley & Balbus 2002, Igumenshchev et al 2003, Pen et al 2003, Pang et al 2011, McKinney et al 2012, Narayan et al 2012. A key conclusion of most such simulations to date is that the net accretion rate through the inner edge of the torus at r = r in is substantially reduced (by a factor ∼r in /R 0 ) from the feeding rate set by the outer torus at r = R 0 , consistent with both CDAF and ADIOS models (e.g., Yuan et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Nuclear Dominated Accretion Flows in Two Dimensions. I. Torus Evolution With Parametric Microphysics

Fernández

Metzger

2013

ApJ

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We explore the evolution of radiatively inefficient accretion disks in which nuclear reactions are dynamically important ("Nuclear Dominated Accretion Flows" or NuDAFs). Examples of such disks are those generated by the merger of a white dwarf with a neutron star or black hole, or by the collapse of a rotating star. Here, we present two-dimensional hydrodynamic simulations that systematically explore the effect of adding a single nuclear reaction to a viscous torus. The equation of state, anomalous shear stress, and nuclear reactions are given parametric forms. Our results point to the existence of two qualitatively different regimes of NuDAF evolution: (1) steady accretion with quiescent burning or (2) detonation of the disk. These outcomes are controlled primarily by the ratio Ψ of the nuclear energy released to the enthalpy at the burning radius. Disks detonate if Ψ exceeds a critical value Ψ crit ∼ 1, and if burning occurs in regions where neutrino cooling is unimportant. Thermonuclear runaways are seeded by the turbulent mixing of hot ash with cold fuel at the burning front. Disks with Ψ < Ψ crit do not explode, but instead power a persistent collimated outflow of unbound material composed primarily of ash, with a mass-loss rate that increases with Ψ. We discuss the implications of our results for supernova-like counterparts from astrophysical events in the NuDAF regime. In particular, detonations following a white dwarf-neutron star merger could account for some subluminous Type Ia supernovae, such as the class defined by SN 2002cx.

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The Fate of Nonradiative Magnetized Accretion Flows: Magnetically Frustrated Convection

Cited by 74 publications

References 24 publications

Neutrino‐dominated Accretion and Supernovae

Neutrino‐dominated Accretion and Supernovae

Large Magneto-ionic Variations toward the Galactic Center Magnetar, PSR J1745-2900

Nuclear Dominated Accretion Flows in Two Dimensions. I. Torus Evolution With Parametric Microphysics

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