Energetics of accretion disk around black holes in Einstein–Gauss–Bonnet gravity
Ikrom Ergashov (Institute for Advanced Studies, New Uzbekistan University, Movarounnahr Str. 1, Tashkent, 100000, Uzbekistan)
; Bakhtiyor Narzilloev (Institute for Advanced Studies, New Uzbekistan University, Movarounnahr Str. 1, Tashkent, 100000, Uzbekistan); Ibrar Hussain (School of Electrical Engineering and Computer Science, National University of Sciences and Technology, H-12, Islamabad, Pakistan, Research Center of Astrophysics and Cosmology, Khazar University, 41 Mehseti Street, Baku, AZ1096, Azerbaijan); Ahmadjon Abdujabbarov (Institute of Nuclear Physics, Ulugbek 1, Tashkent, 100214, Uzbekistan, Tashkent State Technical University, Tashkent, 100095, Uzbekistan, School of Physics, Harbin Institute of Technology, Harbin, 150001, People’s Republic of China); Bobomurat Ahmedov (Institute of Theoretical Physics, National University of Uzbekistan, Tashkent, 100174, Uzbekistan, School of Physics, Harbin Institute of Technology, Harbin, 150001, People’s Republic of China, Institute for Advanced Studies, New Uzbekistan University, Movarounnahr Str. 1, Tashkent, 100000, Uzbekistan)
We investigate the spacetime geometry and astrophysical properties of a static, spherically symmetric black hole in the context of Einstein–Gauss–Bonnet gravity, characterized by a Gauss–Bonnet coupling constant $$\kappa $$ and a non-electromagnetic geometric charge $\textit{Q}$. The black hole solution reduces to the Reissner–Nordstrom or Schwarzschild spacetime in the appropriate limits. We analyze the influence of the parameters $$\kappa $$ and $\textit{Q}$ on the event horizon properties, the innermost stable circular orbit, and the spacetime metric behavior. In the framework of the Novikov–Thorne thin disk model, we compute the flux, temperature, and spectrum of the accretion disk surrounding the black hole. Our results show that the parameters $$\kappa $$ and $\textit{Q}$ significantly affect the disk’s thermal properties and radiation efficiency. Additionally, we demonstrate that the combined effect of these parameters can mimic the role of spin in Kerr black holes, allowing for degeneracy between rotation and geometric corrections. These findings offer potential observational signatures of modified gravity effects in high-energy astrophysical environments.
