scholarly journals Rotating black holes in Einstein-dilaton-Gauss-Bonnet gravity with finite coupling

2015 ◽  
Vol 92 (8) ◽  
Author(s):  
Andrea Maselli ◽  
Paolo Pani ◽  
Leonardo Gualtieri ◽  
Valeria Ferrari
Keyword(s):  
Black Holes ◽  
Bonnet Gravity ◽  
Rotating Black Holes

scholarly journals A new metric for rotating black holes in Gauss—Bonnet gravity

2011 ◽  
Vol 20 (5) ◽  
pp. 050401 ◽  
Author(s):  
Rui-Hong Yue ◽  
De-Cheng Zou ◽  
Tian-Yi Yu ◽  
Zhan-Ying Yang
Keyword(s):  
Black Holes ◽  
Bonnet Gravity ◽  
Rotating Black Holes

scholarly journals Thin accretion disks around rotating black holes in 4D Einstein–Gauss–Bonnet gravity

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Mohaddese Heydari-Fard ◽  
Malihe Heydari-Fard ◽  
Hamid Reza Sepangi
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Accretion Disk ◽  
Accretion Disks ◽  
Coupling Parameter ◽  
Energy Conversion Efficiency ◽  
Bonnet Gravity ◽  
Stable Circular Orbit ◽  
Rotating Black Holes ◽  
Kerr Black Holes

AbstractRecently, Kumar and Ghosh have derived Kerr-like rotating black hole solutions in the framework of four-dimensional Einstein–Gauss–Bonnet theory of gravity and investigated the black hole shadow. Using the steady-state Novikov–Thorne model, we study thin accretion disk processes for such rotating black holes including the energy flux, temperature distribution, emission spectrum, energy conversion efficiency as well as the radius of the innermost stable circular orbit. We also study the effects of the Gauss–Bonnet coupling parameter $$\alpha $$ α on these quantities. The results are compared to slowly rotating relativistic Kerr black holes which show that for a positive Gauss–Bonnet coupling, thin accretion disks around rotating black holes in four-dimensional Einstein–Gauss–Bonnet gravity are hotter and more efficient than that for Kerr black holes with the same rotation parameter a, while for a negative coupling they are cooler and less efficient. Thus the accretion disk processes may be considered as tools for testing Einstein–Gauss–Bonnet gravity using astrophysical observations.

scholarly journals Black hole hair removal for N = 4 CHL models

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Subhroneel Chakrabarti ◽  
Suresh Govindarajan ◽  
P. Shanmugapriya ◽  
Yogesh K. Srivastava ◽  
Amitabh Virmani
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Degrees Of Freedom ◽  
Microscopic Analysis ◽  
Flat Space ◽  
Special Care ◽  
Hair Removal ◽  
Partition Functions ◽  
Rotating Black Holes

Abstract Although BMPV black holes in flat space and in Taub-NUT space have identical near-horizon geometries, they have different indices from the microscopic analysis. For K3 compactification of type IIB theory, Sen et al. in a series of papers identified that the key to resolving this puzzle is the black hole hair modes: smooth, normalisable, bosonic and fermionic degrees of freedom living outside the horizon. In this paper, we extend their study to N = 4 CHL orbifold models. For these models, the puzzle is more challenging due to the presence of the twisted sectors. We identify hair modes in the untwisted as well as twisted sectors. We show that after removing the contributions of the hair modes from the microscopic partition functions, the 4d and 5d horizon partition functions agree. Special care is taken to present details on the smoothness analysis of hair modes for rotating black holes, thereby filling an essential gap in the literature.

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