Dynamical evolution of the shock cone around 4D Einstein-Gauss Bonnet rotating black hole

Dönmez, Orhan

doi:10.1016/j.physletb.2022.136997

Cited by 12 publications

(20 citation statements)

References 38 publications

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“…These simulations are critical for interpreting the complex dynamics near the black holes, where the gravitational effects significantly influence the behavior of the accreating matter [16][17][18][19][20][21][22][23][24][25]. In recent years, using alternative theories of gravity, the dynamic structure of the shock cone in regions with very strong gravitational forces has been examined [26][27][28]. It has been revealed how the shock cone changes depending on various parameters.…”

Section: Introductionmentioning

confidence: 99%

Bondi–Hoyle accretion around the non-rotating black hole in 4D Einstein–Gauss–Bonnet gravity

Dönmez

2021

Eur. Phys. J. C

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In this paper, the numerical investigation of a Bondi–Hoyle accretion around a non-rotating black hole in a novel four dimensional Einstein–Gauss–Bonnet gravity is investigated by solving the general relativistic hydrodynamical equations using the high resolution shock capturing scheme. For this purpose, the accreated matter from the wind-accreating X-ray binaries falls towards the black hole from the far upstream side of the domain, supersonically. We study the effects of Gauss–Bonnet coupling constant $$\alpha $$ α in 4D EGB gravity on the accreated matter and shock cones created in the downstream region in detail. The required time having the shock cone in downstream region is getting smaller for $$\alpha > 0$$ α > 0 while it is increasing for $$\alpha < 0$$ α < 0 . It is found that increases in $$\alpha $$ α leads violent oscillations inside the shock cone and increases the accretion efficiency. The violent oscillations would cause increase in the energy flux, temperature, and spectrum of X-rays. So the quasi-periodic oscillations (QPOs) are naturally produced inside the shock cone when $$-5 \le \alpha \le 0.8$$ - 5 ≤ α ≤ 0.8 . It is also confirmed that EGB black hole solution converges to the Schwarzschild one in general relativity when $$\alpha \rightarrow 0$$ α → 0 . Besides, the negative coupling constants also give reasonable physical solutions and increase of $$\alpha $$ α in negative directions suppresses the possible oscillation observed in the shock cone.

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Section: Introductionmentioning

confidence: 99%

Bondi–Hoyle accretion around the non-rotating black hole in 4D Einstein–Gauss–Bonnet gravity

Dönmez

2021

Eur. Phys. J. C

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“…The code execution time, with t max = 33000M , is considerably longer than the expected time. Numerical verification has confirmed that the qualitative outcomes of the simulations, such as the presence of quasi-periodic oscillations (QPOs) and instabilities, the location of shocks, and the behavior of the accretion rates, are mostly independent of variations in the grid resolution (Donmez, Orhan 2021;Donmez 2022;Donmez et al 2022). Furthermore, it is believed that positioning the outer boundary far enough away from the region where artifacts possibly produced at the outer boundary do not impact the physical solution.…”

Section: Initial and Boundary Conditionsmentioning

confidence: 68%

“…The code execution time (t max = 30000M ) significantly exceeded the time (∼ 5000M ) required for the model to reach the steady state. It has been verified that the qualitative outcomes of the numerical solutions, such as the presence of quasi-periodic oscillations (QPOs) and instabilities, the location of shocks, and the behavior of the accretion rates, are not significantly influenced by the grid resolution (Donmez, Orhan 2021;Donmez 2022;Donmez et al 2022) Ensuring the accurate treatment of boundaries is crucial to avoid unphysical solutions in numerical simulations. For the inner radial boundary, an outflow boundary condition is implemented, allowing gas to fall into the black hole through a simple zerothorder extrapolation.…”

Section: Initial and Boundary Conditionsmentioning

confidence: 99%

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Study of Asymptotic Velocity in the Bondi–Hoyle Accretion Flows in the Domain of Kerr and 4-D Einstein–Gauss–Bonnet Gravities

2022

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Understanding the physical structures of the accreted matter very close to a black hole in quasars and active galactic nucleus (AGN) is an important milestone to constrain the activities occurring in their centers. In this paper, we numerically investigate the effects of the asymptotic velocities on the physical structures of the accretion disk around the Kerr and Einstein–Gauss–Bonnet (EGB) rapidly rotating black holes. The Bondi–Hoyle accretion is considered with a falling gas towards the black hole in an upstream region of the computational domain. Shock cones are naturally formed in the downstream part of the flow around both black holes. The structure of the cones and the amount of the accreted matter depend on asymptotic velocity V∞ (Mach number) and the types of the gravities (Kerr or EGB). Increasing the Mach number of the in-flowing matter in the supersonic region reduces the shock opening angle and the accretion rates, because of the gas rapidly falling towards the black hole. The EGB gravity leads to an increase in the shock opening angle of the shock cones while the mass-accretion rates dM/dt decrease in EGB gravity with a Gauss–Bonnet (GB) coupling constant α. It is also confirmed that accretion rates and drag forces are significantly altered in the EGB gravity. Our numerical simulation results could be used in identifying the accretion mechanism and physical properties of the accretion disk and black hole in the observed X-rays such as NGC 1313 X-1 and 1313 X-2 and MAXI J1803-298.

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“…According to their results, the disk around the 4D EGB black hole for the positive value of α is more luminous and hotter than the one in General Relativity GR (Heydari-Fard et al 2021). The numerical investigation of a BHL accretion in the 4D EGB extensively was studied in the vicinities of the non-rotating (Donmez, Orhan 2021) and the rotating black holes (Donmez 2022). They discussed the effect of GB coupling constant α on the shock cone structure created during the formation of the accretion disk.…”

Section: Introductionmentioning

confidence: 99%

Study of Asymptotic Velocity in the Bondi-Hoyle Accretion Flows in the Domain of Kerr and 4-D Einstein-Gauss-Bonnet Gravities

Dönmez¹,

Doğan²,

Şahin³

2022

Preprint

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Understanding the physical structures of the accreated matter very close to the black hole in quasars and active galactic nucleus (AGNs) is an important milestone to constrain the activities occurring in their centers. In this paper, we numerically investigate the effects of the asymptotic velocities on the physical structures of the accretion disk around the Kerr and Einstein-Gauss-Bonnet (EGB) rapidly rotating black holes. The Bondi-Hoyle accretion is considered with a falling gas towards the black hole in upstream region of the computational domain. The shock cones are naturally produced in the downstream part of the flow around both black holes. It is found that the structure of the cones and the amount of the accreated matter depend on asymptotic velocity V ∞ (Mach number) and the types of the gravities (Kerr or EGB). Increasing the Mach number of the inflowing matter in the supersonic region causes the shock opening angle and accretion rates getting smaller because of the rapidly falling gas towards the black hole. The EGB gravity leads to an increase in the shock opening angle of the shock cones while the mass accretion rates Ṁ are decreasing in EGB gravity with a Gauss-Bonnet (GB) coupling constant α. It is also confirmed that accretion rates and drag forces are significantly altered in the EGB gravity. Our numerical simulation results could be used to identify the accreation mechanism and physical properties of the accretion disk and black hole in the observed X− rays such as NGC 1313 X − 1 and 1313 X − 2 and MAXI J1803 − 298.

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Dynamical evolution of the shock cone around 4D Einstein-Gauss Bonnet rotating black hole

Cited by 12 publications

References 38 publications

Bondi–Hoyle accretion around the non-rotating black hole in 4D Einstein–Gauss–Bonnet gravity

Bondi–Hoyle accretion around the non-rotating black hole in 4D Einstein–Gauss–Bonnet gravity

Study of Asymptotic Velocity in the Bondi–Hoyle Accretion Flows in the Domain of Kerr and 4-D Einstein–Gauss–Bonnet Gravities

Study of Asymptotic Velocity in the Bondi-Hoyle Accretion Flows in the Domain of Kerr and 4-D Einstein-Gauss-Bonnet Gravities

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