Accretion of a massive magnetized torus on a rotating black hole

Barkov, Maxim V.; Baushev, A. N.

doi:10.1016/j.newast.2010.07.001

Cited by 47 publications

(47 citation statements)

References 63 publications

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“…If the wind from the torus propagates with velocity v w ≈ 0.1c (see Barkov & Baushev 2011), then in 2.4 s it would expand to r w ≈ 7 × 10 9 cm. Thus, the jet opening angle is…”

Section: 2mentioning

confidence: 99%

GRB 170817A Associated with GW170817: Multi-frequency Observations and Modeling of Prompt Gamma-Ray Emission

Pozanenko

Barkov

Minaev

et al. 2018

ApJL

124

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We present our observations of electromagnetic transients associated with GW170817/GRB 170817A using optical telescopes of Chilescope observatory and Big Scanning Antenna (BSA) of Pushchino Radio Astronomy Observatory at 110 MHz. The Chilescope observatory detected an optical transient of ∼ 19 m on the third day in the outskirts of the galaxy NGC 4993; we continued observations following its rapid decrease. We put an upper limit of 1.5 × 10 4 Jy on any radio source with a duration of 10-60 s which may be associated with GW170817/GRB 170817A. The prompt gamma-ray emission consists of two distinctive components -a hard short pulse delayed by ∼ 2 seconds with respect to the LIGO signal and softer thermal pulse with T ∼ 10 keV lasting for another ∼ 2 seconds. The appearance of a thermal component at the end of the burst is unusual for short GRBs. Both the hard and the soft components do not satisfy the Amati relation, making GRB 170817A distinctively different from other short GRBs. Based on gamma-ray and optical observations, we develop a model for the prompt high-energy emission associated with GRB 170817A. The merger of two neutron stars creates an accretion torus of ∼ 10 −2 M , which supplies the black hole with magnetic flux and confines the BlandfordZnajek-powered jet. We associate the hard prompt spike with the quasispherical breakout of the jet from the disk wind. As the jet plows through the wind with subrelativistic velocity, it creates a radiation-dominated shock that heats the wind material to tens of kiloelectron volts, producing the soft thermal component.

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“…If the wind from the torus propagates with velocity v w ≈ 0.1c (see Barkov & Baushev 2011), then in 2.4 s it would expand to r w ≈ 7 × 10 9 cm. Thus, the jet opening angle is…”

Section: 2mentioning

confidence: 99%

GRB 170817A Associated with GW170817: Multi-frequency Observations and Modeling of Prompt Gamma-Ray Emission

Pozanenko

Barkov

Minaev

et al. 2018

ApJL

124

View full text Add to dashboard Cite

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“…MHD disk simulations with neutrino cooling have been carried out in two dimensions beginning from analytic, constant angular momentum equilibrium tori by several groups [53][54][55][56], and recently in three dimensions by Siegel and Metzger [57]. They identify the MRI, with associated heating, neutrino emission, and powerful outflows.…”

mentioning

confidence: 99%

“…These neglected features will most likely have strong effects in the early, and most neutrino luminous, postmerger phase. In addition, the two-dimensional (axisymmetric) simulations [53][54][55][56] are affected by the known differences between the saturation of the MRI in two dimensions vs three dimensions [58,59], including the impossibility of an axisymmetric dynamo [60,61].…”

mentioning

confidence: 99%

Evolution of the magnetized, neutrino-cooled accretion disk in the aftermath of a black hole-neutron star binary merger

et al. 2018

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Black hole-torus systems from compact binary mergers are possible engines for gamma-ray bursts (GRBs). During the early evolution of the postmerger remnant, the state of the torus is determined by a combination of neutrino cooling and magnetically driven heating processes, so realistic models must include both effects. In this paper, we study the postmerger evolution of a magnetized black hole-neutron star binary system using the Spectral Einstein Code (SpEC) from an initial postmerger state provided by previous numerical relativity simulations. We use a finite-temperature nuclear equation of state and incorporate neutrino effects in a leakage approximation. To achieve the needed accuracy, we introduce improvements to SpEC's implementation of general-relativistic magnetohydrodynamics (MHD), including the use of cubed-sphere multipatch grids and an improved method for dealing with supersonic accretion flows where primitive variable recovery is difficult. We find that a seed magnetic field triggers a sustained source of heating, but its thermal effects are largely cancelled by the accretion and spreading of the torus from MHD-related angular momentum transport. The neutrino luminosity peaks at the start of the simulation, and then drops significantly over the first 20 ms but in roughly the same way for magnetized and nonmagnetized disks. The heating rate and disk's luminosity decrease much more slowly thereafter. These features of the evolution are insensitive to grid structure and resolution, formulation of the MHD equations, and seed field strength, although turbulent effects are not fully converged.

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“…These models were axially and vertically averaged, and used the classical α-parameter prescription for the viscosity [1][2][3][4][5][6][7][8][9]. More recently, accretion flows are described by fully relativistic MHD computations (e.g., [10,11] ). This method has also been applied recently to describe the central engine of a putative gamma ray burst which could be associated with the event GW150914 [12].…”

Section: Introductionmentioning

confidence: 99%

Black Hole Accretion in Gamma Ray Bursts

et al. 2017

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Abstract:We study the structure and evolution of the hyperaccreting disks and outflows in the gamma ray bursts central engines. The torus around a stellar mass black hole is composed of free nucleons, Helium, electron-positron pairs, and is cooled by neutrino emission. Accretion of matter powers the relativistic jets, responsible for the gamma ray prompt emission. The significant number density of neutrons in the disk and outflowing material will cause subsequent formation of heavier nuclei. We study the process of nucleosynthesis and its possible observational consequences. We also apply our scenario to the recent observation of the gravitational wave signal, detected on 14 September 2015 by the two Advanced LIGO detectors, and related to an inspiral and merger of a binary black hole system. A gamma ray burst that could possibly be related with the GW150914 event was observed by the Fermi satellite. It had a duration of about 1 s and appeared about 0.4 s after the gravitational-wave signal. We propose that a collapsing massive star and a black hole in a close binary could lead to the event. The gamma ray burst was powered by a weak neutrino flux produced in the star remnant's matter. Low spin and kick velocity of the merged black hole are reproduced in our simulations. Coincident gravitational-wave emission originates from the merger of the collapsed core and the companion black hole.

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Accretion of a massive magnetized torus on a rotating black hole

Cited by 47 publications

References 63 publications

GRB 170817A Associated with GW170817: Multi-frequency Observations and Modeling of Prompt Gamma-Ray Emission

GRB 170817A Associated with GW170817: Multi-frequency Observations and Modeling of Prompt Gamma-Ray Emission

Evolution of the magnetized, neutrino-cooled accretion disk in the aftermath of a black hole-neutron star binary merger

Black Hole Accretion in Gamma Ray Bursts

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