Research Projects

The proposed project aims to understand quasinormal ringing (QNMs), echoes, and shadows of different astrophysical compact objects and explore relationships between these phenomena. The project will focus on a well-defined mathematical approach to QNMs, considering the study of dissipative systems, and a more application-oriented approach to the shadow and echo aspects. Priorities will be given to regular black holes, naked singularities, and worm holes. The project will extend previous work on the shadow of black holes in an expanding universe by considering a general stationary axisymmetric metric and including the accretion process. The researchers will generalize their work to include rotating black holes in an expanding universe with accreting matter and look for the shadow. The project will also investigate the relationship between the shadow parameters of compact objects and the echo profile. They will prove that the comoving velocity, which is essential for obtaining the shadow, does not require any closed form transformation function in black hole spacetime. The formalism will be constrained to Einstein's general theory of relativity and modified gravity theories. The project will also generalize the scheme to a broader area, incorporating rotating black holes in an expanding universe with accreting matter and looking for the shadow. The ultimate goal is to determine if there is any relation between the shadow parameters of compact objects and the echo profile.