Even parity potential for spacetimes with Gaussian matter source and its associated QNM spectra

Abstract: We have obtained the general form of even mode potential function for the gravitational perturbation of a static spherically symmetric spacetime. Considering the minimal-spread Gaussian matter source, parameterized by a smearing length scale {\Theta}, the associated quasinormal mode (QNM) frequencies are computed numerically using the well known WKB formula. A comparative study on the accuracy of the results based on different approximation orders of the WKB formula indicates that the smearing parameter {\Theta} has an upper bound, beyond which the spectra of odd and even modes deviate from their usual isospectral nature.