Gravitational Wave Cosmology in Gauss-Bonnet Gravity

In this talk, we will discuss the study of gravitational waves produced by remote astrophysical sources which then propagate in our inhomogeneous universe through cosmic distances. We will look at how the Gauss-Bonnet term affects the gravitational waves through the geometric optics approximation over a homogeneous background under the assumption that the gravitational wave speed is set as c_T = 1. By applying the equations of motion for an FRLW universe, we find solutions to the scalar field and potential for a vacuum case and during the three typical epochs of the evolution of the universe, dominated by radiation, dust, and dark energy. We finally study how GW propagation is affected by each epoch from the scalar fields.