Gravitational waves in braneworlds after multi-messenger events

Abstract: The GW170817 event opened a new window to test modifications to General Relativity with the aim of discard or impose strong constraints in extra dimension theories of gravity. Concerning these theories, the Randall-Sundrum brane-world theory -- 4+1 spacetime model where its covariant Einstein field equations are composed with new extra terms that comes from extra dimensions -- is begin tested in the multi-messenger astronomy field. In the same context, the aim of this paper is to impose new constrictions through measurements of the time-delay between the gravitational and electromagnetic signals: GW170817 and the recent S190425z, over the free cosmological parameters of this modified model. We assume that Gravitational Waves travel along a shortcut on the extra dimension. In addition, we consider the standard $\Lambda$CDM model and perform a likelihood analysis in order to study effects like the $H_0$ tension in comparison to this extra-dimensional theory, obtaining a reduced $H_0$ value of the order of $0.2\%$ in the low energy limit of this theory.