FABRIS , Júlio C.

Scalar–tensor (ST) gravity is considered in the case where the scalar is an external field. We show that general relativity (GR) and usual ST gravity are particular cases of the external scalar–tensor (EST) gravity. It is shown with a particular cosmological example that it is possible to join a part of a GR solution to a part of a ST one such...

In this paper we revisit the analysis of the ringdown frequencies in the form of quasi-normal modes for Schwarzschild,Schwarzschild de-Sitter and Reissner-Nordstr\"om space-times. We plot these frequencies, using the third-order WKB semi-analytical method against the mass, charge and cosmological constant for each corresponding space-time for...