Images of a thin accretion disk around Kerr Black Hole with synchronized scalar hair

Abstract We study possible observable images of a thin accretion disk around rotating hairy black holes with two non-trivial time-periodic scalar fields. Such black holes are a viable alternative to the Kerr black hole, having a much more complicated geodesic structure and resulting accretion disks. We investigate how the different amounts of scalar hair around the black holes, quantified by a normalized charge, alter the direct and indirect images of the disk. Our results show that for high values of this charge, close to a boson star limit, chaotic disk images are observed with multiple small, disconnected components. For moderately large amounts of scalar hair and corresponding normalized charge, although the images still exhibit chaotic behavior, a dominant central dark region component emerges. For lower values of the normalized charge, the accretion disk images qualitatively resemble those for the Kerr black hole.