Thin accretion disk signatures of scalarized black holes in Einstein-scalar-Gauss-Bonnet gravity

• Published in: Physics Letters B
• Main Authors: Mohaddese Heydari-Fard, Hamid Reza Sepangi
• Format: Article
• Language: English
• Published: Elsevier 2021-05-01
• Subjects: Accretion and accretion disk; Physics of black holes; Modified theories of gravity
• Online Access: http://www.sciencedirect.com/science/article/pii/S0370269321002161

Einstein-scalar-Gauss-Bonnet gravity has recently been known to exhibit spontaneous scalarization. In the presence of the Gauss-Bonnet term the no-hair theorem can be evaded and novel black hole solutions with non-trivial scalar fields have been found besides the general relativistic solutions. In this paper, we aim to investigate the possibility of observationally testing Einstein-scalar-Gauss-Bonnet gravity using thin accretion disk properties around such scalarized black holes. Using the Novikov-Thorne model, we numerically calculate the electromagnetic flux, temperature distribution, emission spectrum, innermost stable circular orbits and energy conversion efficiency of accretion disks around such black holes and compare the results with the standard general relativistic Schwarzschild solution. We find that the accretion disks around scalarized black holes are hotter and more luminous than in general relativity.