Abstract
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.
Recommended Citation
O. Donmez et al., "Study of Asymptotic Velocity in the Bondi–Hoyle Accretion Flows in the Domain of Kerr and 4-D Einstein–Gauss–Bonnet Gravities," Universe, vol. 8, no. 9, MDPI, Sep 2022.
The definitive version is available at https://doi.org/10.3390/universe8090458
Department(s)
Materials Science and Engineering
Publication Status
Open Access
Keywords and Phrases
Rotating Black Hole; EGB Gravity; Shock Cone; Numerical Relatinity; X-ray
International Standard Serial Number (ISSN)
2218-1997
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2026 The Authors, All rights reserved
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution 4.0 License.
Publication Date
2022-09-02
Comments
Acknowledgements: All simulations were performed using the Phoenix High-Performance Computing facility at the American University of the Middle East (AUM), Kuwait.