**Principal investigator:** Anđelo Samsarov

**PI's Host institution:** Ruđer Bošković Institute

**Project duration:** 01/03/2021 - 28/02/2025

## Project Summary

Black holes are predicted by the theory of general relativity as a result of a gravitational collapse of massive astrophysical objects. Among other interesting properties of black holes is a property that they exist in a state of constant arousal. Indeed, realistic black holes can never be fully described by their basic parameters, as they are always in a state of perturbation.

Black hole perturbation is followed by a ringdown phase which is dominated by quasinormal modes (QNM). These modes may provide key signature of the gravitational waves.

During the ringdown phase, black holes gradually relax from the initial perturbation by emitting gravitational waves and presumed Hawking radiation. Notably, the presence of a deformed spacetime structure may distort this signal. In order to account for such effects, in this project we plan to utilise the methods of noncommutative geometry (NC) in order to construct and devise appropriate physical models which would be able to deal with new circumstances. The aim of this project is to invetigate the scalar, Dirac, vector and gravitational QNMs resulting from perturbations of realistic 4-dimensional black holes in a presence of quantized spacetime. The same setting of NC geometry we plan to apply in studying the impact of deformation on both the symmetry and the dispersion relations as revealed in a propagation of high energy gamma rays resulting from distant gamma ray bursts.