Quasinormal modes of Einstein--scalar--Gauss--Bonnet black holes

In this paper, we investigate quasinormal modes of scalar and electromagnetic fields in the background of Einstein--scalar--Gauss--Bonnet (EsGB) black holes. Using the scalar and electromagnetic field equations in the vicinity of the EsGB black hole, we study nature of the effective potentials. The dependence of real and imaginary parts of the fundamental quasinormal modes on parameter $p$ (which is related to the Gauss--Bonnet coupling parameter $\alpha$) for different values of multipole numbers $l$ are studied. We analyzed the effects of massive scalar fields on the EsGB black hole, which tells us the existence of quasi--resonances. In the eikonal regime, we find the analytical expression for the quasinormal frequency and show that the correspondence between the eikonal quasinormal modes and null geodesics is valid in the EsGB theory for the test fields. Finally, we study grey-body factors of the electromagnetic fields for different multipole numbers $l$, which deviates from Schwarzschild's black hole.